Thread: How is Sand Formed?

The orthodox view is that sand particles are crystal grains that have fallen out of crystalline rock due to weathering.

But if this is so then why do sand particles not come in an array of vastly differing sizes? The grain size of granite for example is huge whereas for other rock the grain size is far smaller than the average sand particle.

Further if sand comes from crystalline rock then we ought to be able to see this happening. For example why aren’t weathering crystalline rocks rough like sand paper to the touch and why do we not see piles of sand at the base of cliffs formed from crystalline rock? It is true certain types of sandstone can erode into piles of sand depending on the cementing material holding the sand particles together, but this does not explain where the sand came from that the sandstone was made from in the first place.

Why is it that we see sandy beaches on coastlines where crystalline rock is absent and where the nearest rivers have flowed through areas of sedimentary rock where crystalline rock is absent?

It is known that waterborne quartz is able to form sedimentary rock but can this waterborne mineral also not sometimes precipitate out of solution in certain circumstances to form sand particles?

Anybody out there have any opinions on this?

Originally Posted by galexander

The orthodox view is that sand particles are crystal grains that have fallen out of crystalline rock due to weathering.

Sort of, but it's very rare that the crystals won't have been reworked at all. Transportation, such as in a river, fractures and rounds the grains.

Originally Posted by galexander

But if this is so then why do sand particles not come in an array of vastly differing sizes? The grain size of granite for example is huge whereas for other rock the grain size is far smaller than the average sand particle.

A clastic grain might be made of numerous crystals, or might be a fragment of a much larger crystal.

Originally Posted by galexander

Further if sand comes from crystalline rock then we ought to be able to see this happening.

We can. Follow a river from its source to the sea, and you will see the process, as large pebbles are broken up into increasingly smaller grains, and muds.

Originally Posted by galexander

For example why aren’t weathering crystalline rocks rough like sand paper to the touch and why do we not see piles of sand at the base of cliffs formed from crystalline rock?

Because sand isn't removed from the rock a single grain at a time. Large fragments break off, and are then slowly broken down into smaller particles.

Originally Posted by galexander

It is true certain types of sandstone can erode into piles of sand depending on the cementing material holding the sand particles together, but this does not explain where the sand came from that the sandstone was made from in the first place.

Weathering, erosion, transportation. Generally, in a river, although sometimes by the wind.

Originally Posted by galexander

Why is it that we see sandy beaches on coastlines where crystalline rock is absent and where the nearest rivers have flowed through areas of sedimentary rock where crystalline rock is absent?

As you said above, you can erode sandstones to produce sand. You can also break down carbonates into fine grains.

Originally Posted by galexander

It is known that waterborne quartz is able to form sedimentary rock but can this waterborne mineral also not sometimes precipitate out of solution in certain circumstances to form sand particles?

When you say waterborne quartz, do you mean in solution or do you mean grains transported by currents in the water?

Quartz is insoluble. Quartz-rich sedimentary rocks (sandstones) are formed from deposited layers of quartz-rich sands.

Originally Posted by drowsy turtle

Originally Posted by galexander

The orthodox view is that sand particles are crystal grains that have fallen out of crystalline rock due to weathering.

Sort of, but it's very rare that the crystals won't have been reworked at all. Transportation, such as in a river, fractures and rounds the grains.

Originally Posted by galexander

But if this is so then why do sand particles not come in an array of vastly differing sizes? The grain size of granite for example is huge whereas for other rock the grain size is far smaller than the average sand particle.

A clastic grain might be made of numerous crystals, or might be a fragment of a much larger crystal.

Originally Posted by galexander

Further if sand comes from crystalline rock then we ought to be able to see this happening.

We can. Follow a river from its source to the sea, and you will see the process, as large pebbles are broken up into increasingly smaller grains, and muds.

Originally Posted by galexander

For example why aren’t weathering crystalline rocks rough like sand paper to the touch and why do we not see piles of sand at the base of cliffs formed from crystalline rock?

Because sand isn't removed from the rock a single grain at a time. Large fragments break off, and are then slowly broken down into smaller particles.

Originally Posted by galexander

It is true certain types of sandstone can erode into piles of sand depending on the cementing material holding the sand particles together, but this does not explain where the sand came from that the sandstone was made from in the first place.

Weathering, erosion, transportation. Generally, in a river, although sometimes by the wind.

Originally Posted by galexander

Why is it that we see sandy beaches on coastlines where crystalline rock is absent and where the nearest rivers have flowed through areas of sedimentary rock where crystalline rock is absent?

As you said above, you can erode sandstones to produce sand. You can also break down carbonates into fine grains.

Originally Posted by galexander

It is known that waterborne quartz is able to form sedimentary rock but can this waterborne mineral also not sometimes precipitate out of solution in certain circumstances to form sand particles?

When you say waterborne quartz, do you mean in solution or do you mean grains transported by currents in the water?

Quartz is insoluble. Quartz-rich sedimentary rocks (sandstones) are formed from deposited layers of quartz-rich sands.

But quartz is soluble in water though:

http://adsabs.harvard.edu/abs/1962GeCoA..26.1029M

You say

We can. Follow a river from its source to the sea, and you will see the process, as large pebbles are broken up into increasingly smaller grains, and muds.

but how do pebbles get broken up in rivers!?

In my opinion the reason why pebbles get rounded in the first place in rivers and indeed lakes is because they are slowly dissolving.

Originally Posted by galexander

but how do pebbles get broken up in rivers!?

Partly by abrasion or fracturing when they are tumbled and knocked against other rocks as the water carries them along.

Originally Posted by galexander

But quartz is soluble in water though:

http://adsabs.harvard.edu/abs/1962GeCoA..26.1029M

Yes, 6ppm at 25 celcius - which is far warmer than most aqueous environments at the surface anyway.

Originally Posted by galexander

You say

We can. Follow a river from its source to the sea, and you will see the process, as large pebbles are broken up into increasingly smaller grains, and muds.

but how do pebbles get broken up in rivers!?

In essence, by being knocked repeatedly against other rocks.

Originally Posted by galexander

In my opinion the reason why pebbles get rounded in the first place in rivers and indeed lakes is because they are slowly dissolving.

Simply not the case. Rocks with angular clasts such as breccias can be percolated by groundwater for millions of years, and the clasts don't become rounded.

Originally Posted by drowsy turtle

Originally Posted by galexander

But quartz is soluble in water though:

http://adsabs.harvard.edu/abs/1962GeCoA..26.1029M

Yes, 6ppm at 25 celcius - which is far warmer than most aqueous environments at the surface anyway.

Originally Posted by galexander

You say

We can. Follow a river from its source to the sea, and you will see the process, as large pebbles are broken up into increasingly smaller grains, and muds.

but how do pebbles get broken up in rivers!?

In essence, by being knocked repeatedly against other rocks.

Originally Posted by galexander

In my opinion the reason why pebbles get rounded in the first place in rivers and indeed lakes is because they are slowly dissolving.

Simply not the case. Rocks with angular clasts such as breccias can be percolated by groundwater for millions of years, and the clasts don't become rounded.

But drowsy turtle if quartz is partly soluble in water then stones and rocks would therefore very gradually dissolve away in the presence of water.

And don't forget you also get rounded stones and pebbles in lakes in the absence of strong currents.

Originally Posted by galexander

But drowsy turtle if quartz is partly soluble in water then stones and rocks would therefore very gradually dissolve away in the presence of water.

In the paper you cited, the quartz was dissolved at hight pressure and temperature, then cooled down to 25 degrees celcius, at which point most of the silica had re-precipitated, leaving only 6ppm in solution. At low temperatures, quartz will not dissolve at all, even though a very small concentration could theoretically remain in solution.

Quartz is chemically identical to glass; it is the crystalline form of silica whereas glass is amorphous. I'm sure you'll agree that glass does not tend to dissolve?

Originally Posted by galexander

And don't forget you also get rounded stones and pebbles in lakes in the absence of strong currents.

Pebbles do not form in-situ in lakes, since there are no erosional processes. Lakes are usually depotitional, rathe than erosional, environments. Pebbles in lakes were invariably transported there from elsewhere.

Originally Posted by drowsy turtle

Originally Posted by galexander

But drowsy turtle if quartz is partly soluble in water then stones and rocks would therefore very gradually dissolve away in the presence of water.

In the paper you cited, the quartz was dissolved at hight pressure and temperature, then cooled down to 25 degrees celcius, at which point most of the silica had re-precipitated, leaving only 6ppm in solution. At low temperatures, quartz will not dissolve at all, even though a very small concentration could theoretically remain in solution.

Quartz is chemically identical to glass; it is the crystalline form of silica whereas glass is amorphous. I'm sure you'll agree that glass does not tend to dissolve?

Originally Posted by galexander

And don't forget you also get rounded stones and pebbles in lakes in the absence of strong currents.

Pebbles do not form in-situ in lakes, since there are no erosional processes. Lakes are usually depotitional, rathe than erosional, environments. Pebbles in lakes were invariably transported there from elsewhere.

The paper quoted says the following about the solubility of quartz in water:

It is concluded that quartz was precipitated at room temperature from this supersaturated solution and that 6 p.p.m. is essentially the true solubility of quartz at 25°C.

Which in my books is quite clearly stating that at room temperature quartz will dissolve at 6 p.p.m.

No quartz is not chemically identical to glass. Glass is manufactured from quartz which has been superheated. Naturally occurring glass i.e. obsidian, is brittle just like glass but it is no way as hard like a quartz pebble on the beach.

Next time you see the shoreline of a lake you will see plenty of large rounded boulders which never just rolled there.

And don't forget you also get rounded stones and pebbles in lakes in the absence of strong currents.

rocks in lakes get hammered by waves, ice, currents moving sand around, and other sources of much abrasion

But if this is so then why do sand particles not come in an array of vastly differing sizes?

They do. In any given sandy location, of course, you most likely would find the deposited sand sorted by size and mass by the depositional process.

But even in such sorted depositions, you can often find layers of larger or smaller sized grains by digging, wading out past the active wave line, etc. It's common on lakeshores in my region (Minnesota) to find the sand turning to gravel and then cobbles by degrees as you wade in and out of the water.

Originally Posted by galexander

Which in my books is quite clearly stating that at room temperature quartz will dissolve at 6 p.p.m.

The difference is between actively dissolving, and remaining in solution. Quartz will remain in solution at very low conentrations at room temperature, but it will not actively dissolve.

Originally Posted by galexander

No quartz is not chemically identical to glass.

Chemically identical may have been the wrong words to use, but they are both formed from a single compound; silica.

Originally Posted by galexander

Glass is manufactured from quartz which has been superheated. Naturally occurring glass i.e. obsidian, is brittle just like glass but it is no way as hard like a quartz pebble on the beach.

Obsidian is an aggregate of different minerals in their amorphous habit. When we refer to obsidian as a glass, we mean only that it is an amorphous solid.

Originally Posted by galexander

Next time you see the shoreline of a lake you will see plenty of large rounded boulders which never just rolled there.

The Earth's history is long and dynamic. In recent times, for instance, we have had glaciation over much of the Northern Hemisphere, which plucked rocks and boulders from their original positions and deposited them randomly around the world.

Originally Posted by drowsy turtle

Originally Posted by galexander

Which in my books is quite clearly stating that at room temperature quartz will dissolve at 6 p.p.m.

The difference is between actively dissolving, and remaining in solution. Quartz will remain in solution at very low conentrations at room temperature, but it will not actively dissolve.

Originally Posted by galexander

No quartz is not chemically identical to glass.

Chemically identical may have been the wrong words to use, but they are both formed from a single compound; silica.

Originally Posted by galexander

Glass is manufactured from quartz which has been superheated. Naturally occurring glass i.e. obsidian, is brittle just like glass but it is no way as hard like a quartz pebble on the beach.

Obsidian is an aggregate of different minerals in their amorphous habit. When we refer to obsidian as a glass, we mean only that it is an amorphous solid.

Originally Posted by galexander

Next time you see the shoreline of a lake you will see plenty of large rounded boulders which never just rolled there.

The Earth's history is long and dynamic. In recent times, for instance, we have had glaciation over much of the Northern Hemisphere, which plucked rocks and boulders from their original positions and deposited them randomly around the world.

To be fair drowsy turtle the website speaks of the SOLUBILITY and not the RATIO OF COMPLETE PRECIPITATION for quartz.

And if quartz is not water soluble then how is it that quartz is an important cementing material in sedimentary rock?

http://www.britannica.com/EBchecked/...47/cementation

cementation, in geology, hardening and welding of clastic sediments (those formed from preexisting rock fragments) by the precipitation of mineral matter in the pore spaces. It is the last stage in the formation of a sedimentary rock. The cement forms an integral and important part of the rock, and its precipitation affects the porosity and permeability of the rock. Many minerals may become cements; the most common is silica (generally quartz), but calcite and other carbonates also undergo the process, as well as iron oxides, barite, anhydrite, zeolites, and clay minerals.

And this from the Hutchinson Encyclopaedia:

Silica cementation takes place below the water table surface; its source is groundwater.

It's not quartz in solution it's silicic acid; H four Si O four. Simple (congruent) solution.

From Boggs, Principles of Sedimentology and Stratigraphy

Most of the silica set free during hydroylsis goes into solution as silicic acid; however, some of the silica may separate as colloidal or amorphous silica and be left behind during weathering to combine with aluminum to form clay minerals. Hydrolysis is the primary process by which silicate minerals decompose during weathering

Quartz rich sandstones cemented with silica cement weather very slowly under most climatic conditions

Don't forget Chert.

Originally Posted by Geo

It's not quartz in solution it's silicic acid; H four Si O four. Simple (congruent) solution.

From Boggs, Principles of Sedimentology and Stratigraphy

Most of the silica set free during hydroylsis goes into solution as silicic acid; however, some of the silica may separate as colloidal or amorphous silica and be left behind during weathering to combine with aluminum to form clay minerals. Hydrolysis is the primary process by which silicate minerals decompose during weathering

Quartz rich sandstones cemented with silica cement weather very slowly under most climatic conditions

Don't forget Chert.

Thanks Geo but you just admitted it with your last quote which I re-quote:

Quartz rich sandstones cemented with silica cement weather very slowly under most climatic conditions

Yes, and silica is silicon dioxide, SiO2, is it not?

So silicon dioxide is also a cementing material. And how did it get there to cement sand particles? By precipitation from water perhaps?

And just in case there were any lingering doubts, what about the following on types of cements in sedimentary rock:

Three common types of cement

Calcium- Probably the most common

Easily dissolved in groundwater

H20 + CO2 = H2CO3 (Carbonic Acid)

Will dissolve calcium and put it into solution

Silica - less soluble than calcite

Will form a much harder and stronger cement

Iron Oxide (Fe2O3)

From http://jersey.uoregon.edu/~mstrick/g...dimentary.html

So if quartz IS soluble in water then presumably it can precipitate out of solution in some circumstances.

And what would that precipitate look like? Perhaps it might look like sand.

And what of the quartz containing rocks which were gradually dissolving? What would they look like after a period of time? Perhaps they might become rounded like pebbles?

Originally Posted by galexander

And what would that precipitate look like? Perhaps it might look like sand.

No, it looks like a microcrystalline cement.

Originally Posted by galexander

And what of the quartz containing rocks which were gradually dissolving? What would they look like after a period of time? Perhaps they might become rounded like pebbles?

Weathered igneous rocks just look smoother than unweathered igneous rocks. Being generally impermeable, the individual crystals tend not to be seperated by chemical processes. Pebbles and sands are formed by mechanical weathering, although often in conjunction with chemical processes.

And the rocks don't directly dissolve, they undergo chemical reactions with water and/or its solutes, sometimes forming soluble products.

Originally Posted by drowsy turtle

Originally Posted by galexander

And what would that precipitate look like? Perhaps it might look like sand.

No, it looks like a microcrystalline cement.

Originally Posted by galexander

And what of the quartz containing rocks which were gradually dissolving? What would they look like after a period of time? Perhaps they might become rounded like pebbles?

Weathered igneous rocks just look smoother than unweathered igneous rocks. Being generally impermeable, the individual crystals tend not to be seperated by chemical processes. Pebbles and sands are formed by mechanical weathering, although often in conjunction with chemical processes.

And the rocks don't directly dissolve, they undergo chemical reactions with water and/or its solutes, sometimes forming soluble products.

No, it looks like a microcrystalline cement.

Only if it precipitates out within a sediment. But what if it precipitates out of water to form particles that fall to the bottom of a river?

Weathered igneous rocks just look smoother than unweathered igneous rocks. Being generally impermeable, the individual crystals tend not to be seperated by chemical processes. Pebbles and sands are formed by mechanical weathering, although often in conjunction with chemical processes.

If rocks can dissolve in water then by definition they must erode in water and therefore take on a rounded appearance as a result.

Oh, and by the way drowsy turtle, have you finally conceded the point that quartz IS soluble in water? Yes you have because you said the following with regard to quartz precipitation:

No, it looks like a microcrystalline cement.

Originally Posted by galexander

No, it looks like a microcrystalline cement.

Only if it precipitates out within a sediment. But what if it precipitates out of water to form particles that fall to the bottom of a river?

With the sort of timescale we're looking at, this isn't realistic. And the mineral would precipitate around existing solid material, where it can nucleate. Think of limescale in a kettle, for instance - the carbonates form on the edge of the kettle and grow outwards, they don't form at the top and sink to the bottom.

I therefore reaffirm that we would see a microcrystalline structure.

Originally Posted by galexander

If rocks can dissolve in water then by definition they must erode in water and therefore take on a rounded appearance as a result.

Why by definition?

If the rock was eroded purely by chemical weathering and solution, how would individual pebbles form to start with, to become rounded? Bearing in mind we are starting with an igneous body that might be many km across, are you suggesting that this whole body of rock will dissolve untill it is left as a single, rounded grain of sand?

Before your hypothesis could work, some process would have to fracture the rock into smaller clasts to start with.

And also, as I have already mentioned, we see vast sandstones that have been percolated by groundwater over millions of years, and yet retain their angular clasts, whereas desert sands which never come into contact with water are very often well-rounded.

Originally Posted by galexander

Oh, and by the way drowsy turtle, have you finally conceded the point that quartz IS soluble in water?

I never said quartz is not soluble. What I said was that quartz does not actively dissolve at room temperature and normal pressure. Reaction with solutes in water may also cause the quartz to be corroded at room temperature, for instance by forming silicic acid.

We need to be a little careful here gents. In actively seeking to correct galexander's bizarre ideas we are in danger of throwing the baby out with the silica saturated river water. By some estimates the total volume of silica carried in solution to the oceans equals the volume carried as clasts.

Time permitting I intend to post a thorough treatement of all galexander's questions and points that should clarify his misunderstanding (or deliberate obfuscation).

Originally Posted by drowsy turtle

Originally Posted by galexander

No, it looks like a microcrystalline cement.

Only if it precipitates out within a sediment. But what if it precipitates out of water to form particles that fall to the bottom of a river?

With the sort of timescale we're looking at, this isn't realistic. And the mineral would precipitate around existing solid material, where it can nucleate. Think of limescale in a kettle, for instance - the carbonates form on the edge of the kettle and grow outwards, they don't form at the top and sink to the bottom.

I therefore reaffirm that we would see a microcrystalline structure.

Originally Posted by galexander

If rocks can dissolve in water then by definition they must erode in water and therefore take on a rounded appearance as a result.

Why by definition?

If the rock was eroded purely by chemical weathering and solution, how would individual pebbles form to start with, to become rounded? Bearing in mind we are starting with an igneous body that might be many km across, are you suggesting that this whole body of rock will dissolve untill it is left as a single, rounded grain of sand?

Before your hypothesis could work, some process would have to fracture the rock into smaller clasts to start with.

And also, as I have already mentioned, we see vast sandstones that have been percolated by groundwater over millions of years, and yet retain their angular clasts, whereas desert sands which never come into contact with water are very often well-rounded.

Originally Posted by galexander

Oh, and by the way drowsy turtle, have you finally conceded the point that quartz IS soluble in water?

I never said quartz is not soluble. What I said was that quartz does not actively dissolve at room temperature and normal pressure. Reaction with solutes in water may also cause the quartz to be corroded at room temperature, for instance by forming silicic acid.

Correction drowsy turtle, when you said the following it is what you appear to have been suggesting, not me:

Bearing in mind we are starting with an igneous body that might be many km across, are you suggesting that this whole body of rock will dissolve untill it is left as a single, rounded grain of sand?

And the following:

And also, as I have already mentioned, we see vast sandstones that have been percolated by groundwater over millions of years, and yet retain their angular clasts, whereas desert sands which never come into contact with water are very often well-rounded.

Are you honestly saying it never rains in the desert? Yes deserts are often dry because they have no soil and the dampness evaporates away. But to say it never rains..........doh!

Originally Posted by Ophiolite

We need to be a little careful here gents. In actively seeking to correct galexander's bizarre ideas we are in danger of throwing the baby out with the silica saturated river water. By some estimates the total volume of silica carried in solution to the oceans equals the volume carried as clasts.

Time permitting I intend to post a thorough treatement of all galexander's questions and points that should clarify his misunderstanding (or deliberate obfuscation).

Yes and thank you Ophiolite for backing me in pointing out drowsy turtle's blatant error regarding quartz solubility in water.

Originally Posted by galexander

Correction drowsy turtle, when you said the following it is what you appear to have been suggesting, not me:

Bearing in mind we are starting with an igneous body that might be many km across, are you suggesting that this whole body of rock will dissolve untill it is left as a single, rounded grain of sand?

You are detracting from my point. How exactly is it that you theorise quartzitic sands form in situ as a result of the dissolution of ignous rocks? What causes the rock to seperate into individual grains of quartz, and where have all the other minerals gone?

Originally Posted by galexander

Are you honestly saying it never rains in the desert? Yes deserts are often dry because they have no soil and the dampness evaporates away. But to say it never rains..........doh!

What I am saying, is that if rounded clasts were the result of erosion as you claim, we would expect to see a clear correlation of rounded clasts where water is abundant, and angular clasts (or no clasts at all) where rain is scarce. On the contrary, sands which accumulate in deserts are usually very well-rounded. The accepted explanation is, and has been for decades if not centuries, that clasts become rounded from physical weathering (attrition, abrasion, etc.).

Originally Posted by Ophiolite

We need to be a little careful here gents. In actively seeking to correct galexander's bizarre ideas we are in danger of throwing the baby out with the silica saturated river water. By some estimates the total volume of silica carried in solution to the oceans equals the volume carried as clasts.

I had always thought aqueous silica (in the form of silicic acid) originated from the weathering of silicate minerals, and that quartz did not actively dissolve; even on a geological timescale.

Please do correct me if I am wrong, though

Is there a concept the denialists and kooks *won't* butcher?

Originally Posted by drowsy turtle

I had always thought aqueous silica (in the form of silicic acid) originated from the weathering of silicate minerals, and that quartz did not actively dissolve; even on a geological timescale.

It is being derived from silicates and from quartz. The proportions by which it is derived are not clear. The point made earlier that at 25 deg C the equilibrium concentration is 6ppm with pure water in contact with quartz. This amount rises depending on the nature of the quartz and the impurities in the water. According to the Encyclopedia Brittanica " Typical temperate-climate river watercontains 14 parts per million of silica". Also the equlibrium concentration is about 50 ppm when the pure water is in contact with amorphous silica such as chert.


Galexander, I have not supported your view about quartz solubility. I have simply clarified an important aspect of weathering and mass transport that was in danger of being buired by your peculiar thinking.

Before I respond in detail to all the points you have raised will you be honest and lay out clearly and unambiguously your agenda? Where are you heading with your arguments? Convince me that you are not a creationist trying to play games with us. Over to you.

Originally Posted by Ophiolite

Before I respond in detail to all the points you have raised will you be honest and lay out clearly and unambiguously your agenda? Where are you heading with your arguments? Convince me that you are not a creationist trying to play games with us. Over to you.

i have been following this discussion with some degree of interest, and whilst i don't detect a creationist agenda as such, this and other posts of you, galexander, appear to share a number of characteristics that seem to add up to either a personal hobby-horse or an agenda

i am curious - why do you feel the need to attack established science on grounds that appear to be based more on your misunderstanding of what you're attacking than the actual science you attempt to find fault with ?

as Ophi said, over to you

Originally Posted by Ophiolite

Originally Posted by drowsy turtle

I had always thought aqueous silica (in the form of silicic acid) originated from the weathering of silicate minerals, and that quartz did not actively dissolve; even on a geological timescale.

It is being derived from silicates and from quartz. The proportions by which it is derived are not clear. The point made earlier that at 25 deg C the equilibrium concentration is 6ppm with pure water in contact with quartz. This amount rises depending on the nature of the quartz and the impurities in the water. According to the Encyclopedia Brittanica " Typical temperate-climate river watercontains 14 parts per million of silica". Also the equlibrium concentration is about 50 ppm when the pure water is in contact with amorphous silica such as chert.


Galexander, I have not supported your view about quartz solubility. I have simply clarified an important aspect of weathering and mass transport that was in danger of being buired by your peculiar thinking.

Before I respond in detail to all the points you have raised will you be honest and lay out clearly and unambiguously your agenda? Where are you heading with your arguments? Convince me that you are not a creationist trying to play games with us. Over to you.

I don't have a hidden "Creationist" agenda. I don't have any hidden agenda at all.

My complaint is that scientists tend to live in ivory towers.

And scientists do not appear to accept shades of opinion, everything has to be black or white.

Much of the science we believe in (and I use the word 'believe' with some prudence) is antiquated somewhat. I would go so far as to say that the longer ago a scientific law was proposed, the more likely it is wrong.

Because of this law physics is the worst off, followed by chemistry and then geology.

I would go so far as to say that the longer ago a scientific law was proposed, the more likely it is wrong.

I would say that the longer a scientific law has been around the better it is supported by empirical observation. The longer a scientific law has been around is a testament to it's worth, especially against the baseless attacks of fool's.

Originally Posted by galexander

My complaint is that scientists tend to live in ivory towers.

And scientists do not appear to accept shades of opinion, everything has to be black or white.

Much of the science we believe in (and I use the word 'believe' with some prudence) is antiquated somewhat. I would go so far as to say that the longer ago a scientific law was proposed, the more likely it is wrong.

It appears you have met very few, if any, scientists.

It appears you have read few, if any, research articles in scientific journals, or attended any scientific symposia or conferences.

It appears that your scientific education is minimal, or non-existent.

I make these observations, which may seem harsh, based upon the peculiarity of your beliefs. you could not hold rationally these beliefs if you did know many scientists, if you had read extensively in scientific journals, or if you had a decent science education.

I intend to examine each of your claims/suggestions about geology and demonstrate that your understanding is badly flawed. I welcome any response you care to make to these demonstrations, but I hope you will respond with facts, not assertions. It may be best to do this piecemeal. I shall endeavour to have my first submission ready for you tomorrow, or Friday.

Originally Posted by Ophiolite

Originally Posted by galexander

My complaint is that scientists tend to live in ivory towers.

And scientists do not appear to accept shades of opinion, everything has to be black or white.

Much of the science we believe in (and I use the word 'believe' with some prudence) is antiquated somewhat. I would go so far as to say that the longer ago a scientific law was proposed, the more likely it is wrong.

It appears you have met very few, if any, scientists.

It appears you have read few, if any, research articles in scientific journals, or attended any scientific symposia or conferences.

It appears that your scientific education is minimal, or non-existent.

I make these observations, which may seem harsh, based upon the peculiarity of your beliefs. you could not hold rationally these beliefs if you did know many scientists, if you had read extensively in scientific journals, or if you had a decent science education.

I intend to examine each of your claims/suggestions about geology and demonstrate that your understanding is badly flawed. I welcome any response you care to make to these demonstrations, but I hope you will respond with facts, not assertions. It may be best to do this piecemeal. I shall endeavour to have my first submission ready for you tomorrow, or Friday.

Ophiolite said the following:

It appears you have met very few, if any, scientists.

I have met many scientists professionally, both graduate and Ph.D.

Okay so I am not qualified in Geology but I have a keen interest in the subject. I take an interest in fossil hunting and mineral collecting.

Peer reviewed journals and scientific symposia (for scientists in ivory towers) are one thing Ophiolite but I like to use a little common sense.

one thing that i'm rather puzzled about is your assumption that, just because a theory has been around for several centuries, it must be out of date
how about the other way of looking at it, which is that the theory is still around because it has stood the test of time, and really is a good description of reality ?

also, just because a theory was first invented yonks ago doesn't mean that it has not been refined over the intervening time - it's not like the theory of natural selection is still in the exact format as originally proposed by Darwin : whilst the main threads have stood the test of time, details (and often very important details) have been merged with the original, and the updated version is now more robust and true to nature than the original was

Originally Posted by marnixR

one thing that i'm rather puzzled about is your assumption that, just because a theory has been around for several centuries, it must be out of date
how about the other way of looking at it, which is that the theory is still around because it has stood the test of time, and really is a good description of reality ?

also, just because a theory was first invented yonks ago doesn't mean that it has not been refined over the intervening time - it's not like the theory of natural selection is still in the exact format as originally proposed by Darwin : whilst the main threads have stood the test of time, details (and often very important details) have been merged with the original, and the updated version is now more robust and true to nature than the original was

Well marnixR, you may have a point, especially in the case of Geology.

Alfred Weneger's theories regarding plate tectonics and continental drift have only been established for a few decades now but I think the whole thing is total nonsense. I refuse to accept that we are floating around on a sea of lava. I mean would anyone care to tell me exactly how hot the Earth's core is said to be? And as for Pangaea, I can only compare it to the legends of the lost continent of Atlantis!

Alfred Weneger's theories regarding plate tectonics and continental drift have only been established for a few decades now but I think the whole thing is total nonsense. I refuse to accept that we are floating around on a sea of lava. I mean would anyone care to tell me exactly how hot the Earth's core is said to be? And as for Pangaea, I can only compare it to the legends of the lost continent of Atlantis!

So then how do you, galexander, explain volcanism, the Pacific ring of fire, the Mariana Trench, seismology, the Cascade range?
EDIT; P.S. We're floating around on a sea of magma, not lava. It's not lava until it extrudes, prior to that it's magma.

or the fact that sea-floor spreading has actually been measured using satellites ?

http://oceanlink.island.net/SOLE/tectonics/WCDA.html

Originally Posted by galexander

Alfred Weneger's theories regarding plate tectonics and continental drift have only been established for a few decades now but I think the whole thing is total nonsense. I refuse to accept that we are floating around on a sea of lava. ... And as for Pangaea, I can only compare it to the legends of the lost continent of Atlantis!

Okay, that's your opinion, but what do you know about these subjects?

Originally Posted by galexander

... I refuse to accept that we are floating around on a sea of lava. ...

as an aside, let's remember the definition of reality : "Reality is that which, when you stop believing in it, doesn't go away."

unfortunately, refusing to believe the reality of plate tectonics doesn't make it go away

Originally Posted by galexander

I refuse to accept that we are floating around on a sea of lava.

That's handy, because we're not. The Mantle is largely solid. We know this because S-waves pass through it.

Originally Posted by galexander

I mean would anyone care to tell me exactly how hot the Earth's core is said to be?

I could guestimate, but I couldn't give you an exact figure. It most likely ranges between 4000-8000k, obviously being hotter towards the centre.

Originally Posted by galexander

And as for Pangaea, I can only compare it to the legends of the lost continent of Atlantis!

That's nice. We can, however, determine that lattitude at which igneous rocks formed - essentially by looking at the allignment of diamagnetic molecules within the rocks. When we look at rocks from around the world, we find that all rocks dated at around 250 million years ago formed around the equator. We can also look at things like correlation of terrestrial species (e.g. the same species can be found in the fossil records in South America and Africa around 250 million years ago, and then begin to diverge), the extent of glaciation at this time in the Southern Hemisphere, or even the rate at which the continents are moving currently (see Marnix's post). We can also look at the distribution and age of volcanic islands and seamounts, e.g. the Hawaiian Island chain and the Emperor Seamounts.

If you don't know what I'm talking about, then you haven't done so much as a simple google search.

galexander,
here are my comments on your first points. On each of them you are quite simply completely wrong.

The orthodox view is that sand particles are crystal grains that have fallen out of crystalline rock due to weathering. But if this is so then why do sand particles not come in an array of vastly differing sizes? The grain size of granite for example is huge whereas for other rock the grain size is far smaller than the average sand particle.

Sand particles do come in a full range of sizes, from very fine to very coarse. By definition particles any larger, or smaller, are not sand particles: the larger ones are gravel, or granules, the smaller ones are silt. More than one scale has been proposed for these sizes. Udden (1914) specified diameters from 1/8 mm to 2mm, Wentworth (1922) from 1/16mm to 2mm. Many sediments, from dune sands to offshore bars, turbidites to river point bars, and dozens more, contain sand particles covering these ranges.

You made a laughable criticism of scientists in their ivory towers: it is clear you have never met a geologist. Now before you accuse me of too readily accepting what I have read in a book may I point out the following? I spent more than a cumulative period of four months geological field mapping in a variety of locations in the UK examining first hand a variety of sandstones from the Torridonian of NW Scotland to the Cambrian quartzites of Shropshire; the Old Red Sandstone of Bute to the Calcareous Sandstone of Ayrshire. Set aside that mapping field work and I have examined sandstones, in situ, on four continents, ranging in age from Pre-Cambrian to Tertiary, from tropical jungles, through North African deserts, to Arctic tundra. Beyond that I’ve personally collected and examined well samples representing in excess of 150,000’ of sediment, a substantial portion of which were sandstones. And beyond that I have studied well logs for hundreds of wells, where once again sandstones have been present as an important rock type. Everything I have seen supports the interpretations and conclusions recognised by the experts for over a century.

In short, your first observation is completely wrong. Will you now acknowledge this?

You go on to mention the grain size of granite, which is certainly a coarse grained igneous rock. But the majority of grains in most granite would fit comfortably within the scales of Wentworth and Udden. Equally, particles derived from finer grained rocks fit neatly into the scales as very fine sand, or silt.

In short, your second observation is also completely wrong. Will you now acknowledge this?

Further if sand comes from crystalline rock then we ought to be able to see this happening. For example why aren’t weathering crystalline rocks rough like sand paper to the touch and why do we not see piles of sand at the base of cliffs formed from crystalline rock?

This is exactly what we do see when the grain size and composition of the rocks and type and combination of physical and chemical weathering is appropriate.

Ferromagnesian minerals such as olivine, pyroxene, amphiboles and the plagioclase, and to a lesser extent orthoclase, feldspars are comparatively ‘soft’ so that they will weather, providing the matrix in which will be embedded the more resistant minerals, primarily quartz.

I live a few miles from a major granite body in the Scottish Highlands. Walk up the slopes to one of its peaks and one see the stream beds and footpaths awash with coarse quartz sand grains, weathered from the granite. Look at a ‘cut’ made by a minor landslide and one can view the transition from solid granite, through weathered material to a clay soil rich in quartz grains.

Look in the research literature on this and one will find endless examples.

In short, your third observation is completely wrong. Will you now acknowledge this?

Will you also now acknowledge that you have never studied rocks in the field, or that if you have done so, it has been with blinkered eyes? If we cannot agree on these fundamental points, established by many millions of observations, then there is no point in proceeding any further to the more complex considerations relating to silica solubility, colloid chemistry, reaction coefficients, the distinctions between silica and quartz, etc.

Originally Posted by galexander

Alfred Weneger's theories regarding plate tectonics and continental drift have only been established for a few decades now

Wegner did not have any theories regarding plate tectonics. His notion of continental drift was accurate in establishing that the continents moved, but he was completely wrong on the mechanism and his idea that the continents moved separately from the oceans. Your ignorance on these points; your total misunderstanding of the character of the mantle, which drowsy turtle has noted; your introduction of a strawman discussion on core temperature, when what is more crucial is mantle composition and temperature; and your rejection of Pangea, a continent established by geology, palaeontology, and geophysics, all these combine to highlight the depth of your ignorance.

Alfred Weneger's theories regarding plate tectonics and continental drift have only been established for a few decades now but I think the whole thing is total nonsense. I refuse to accept that we are floating around on a sea of lava. I mean would anyone care to tell me exactly how hot the Earth's core is said to be? And as for Pangaea, I can only compare it to the legends of the lost continent of Atlantis!

"That sounds ridiculous" is not a very convincing argument. What is your basis for disagreement?

Originally Posted by Ophiolite

galexander,
here are my comments on your first points. On each of them you are quite simply completely wrong.

The orthodox view is that sand particles are crystal grains that have fallen out of crystalline rock due to weathering. But if this is so then why do sand particles not come in an array of vastly differing sizes? The grain size of granite for example is huge whereas for other rock the grain size is far smaller than the average sand particle.

Sand particles do come in a full range of sizes, from very fine to very coarse. By definition particles any larger, or smaller, are not sand particles: the larger ones are gravel, or granules, the smaller ones are silt. More than one scale has been proposed for these sizes. Udden (1914) specified diameters from 1/8 mm to 2mm, Wentworth (1922) from 1/16mm to 2mm. Many sediments, from dune sands to offshore bars, turbidites to river point bars, and dozens more, contain sand particles covering these ranges.

You made a laughable criticism of scientists in their ivory towers: it is clear you have never met a geologist. Now before you accuse me of too readily accepting what I have read in a book may I point out the following? I spent more than a cumulative period of four months geological field mapping in a variety of locations in the UK examining first hand a variety of sandstones from the Torridonian of NW Scotland to the Cambrian quartzites of Shropshire; the Old Red Sandstone of Bute to the Calcareous Sandstone of Ayrshire. Set aside that mapping field work and I have examined sandstones, in situ, on four continents, ranging in age from Pre-Cambrian to Tertiary, from tropical jungles, through North African deserts, to Arctic tundra. Beyond that I’ve personally collected and examined well samples representing in excess of 150,000’ of sediment, a substantial portion of which were sandstones. And beyond that I have studied well logs for hundreds of wells, where once again sandstones have been present as an important rock type. Everything I have seen supports the interpretations and conclusions recognised by the experts for over a century.

In short, your first observation is completely wrong. Will you now acknowledge this?

You go on to mention the grain size of granite, which is certainly a coarse grained igneous rock. But the majority of grains in most granite would fit comfortably within the scales of Wentworth and Udden. Equally, particles derived from finer grained rocks fit neatly into the scales as very fine sand, or silt.

In short, your second observation is also completely wrong. Will you now acknowledge this?

Further if sand comes from crystalline rock then we ought to be able to see this happening. For example why aren’t weathering crystalline rocks rough like sand paper to the touch and why do we not see piles of sand at the base of cliffs formed from crystalline rock?

This is exactly what we do see when the grain size and composition of the rocks and type and combination of physical and chemical weathering is appropriate.

Ferromagnesian minerals such as olivine, pyroxene, amphiboles and the plagioclase, and to a lesser extent orthoclase, feldspars are comparatively ‘soft’ so that they will weather, providing the matrix in which will be embedded the more resistant minerals, primarily quartz.

I live a few miles from a major granite body in the Scottish Highlands. Walk up the slopes to one of its peaks and one see the stream beds and footpaths awash with coarse quartz sand grains, weathered from the granite. Look at a ‘cut’ made by a minor landslide and one can view the transition from solid granite, through weathered material to a clay soil rich in quartz grains.

Look in the research literature on this and one will find endless examples.

In short, your third observation is completely wrong. Will you now acknowledge this?

Will you also now acknowledge that you have never studied rocks in the field, or that if you have done so, it has been with blinkered eyes? If we cannot agree on these fundamental points, established by many millions of observations, then there is no point in proceeding any further to the more complex considerations relating to silica solubility, colloid chemistry, reaction coefficients, the distinctions between silica and quartz, etc.

Ophiolite are you telling us that gravel erodes from out of rocks just as sand does?

To be absolutely honest I found your carefully constructed piece on sand formation unconvincing and at best hairsplitting.

I mean what evidence have you seriously presented? I couldn't see any!

To give an example of your complete and utter obscurity I quote the following separate and quite independant paragraph:

Ferromagnesian minerals such as olivine, pyroxene, amphiboles and the plagioclase, and to a lesser extent orthoclase, feldspars are comparatively ‘soft’ so that they will weather, providing the matrix in which will be embedded the more resistant minerals, primarily quartz.

Yes..................and?

Presumably you are referring to specific types of sandstone where the cementing material erodes quite easily leaving the sand particles behind. So why didn't you just say this? But I don't deny this happens Ophiolite. I have seen myself piles of sand under the bases of such sandstone. But not all sandstone is like this, far from it and this still doesn't explain where the sand came from in the first place that the sandstone was formed from.

Originally Posted by drowsy turtle

Originally Posted by galexander

I refuse to accept that we are floating around on a sea of lava.

That's handy, because we're not. The Mantle is largely solid. We know this because S-waves pass through it.

Originally Posted by galexander

I mean would anyone care to tell me exactly how hot the Earth's core is said to be?

I could guestimate, but I couldn't give you an exact figure. It most likely ranges between 4000-8000k, obviously being hotter towards the centre.

Originally Posted by galexander

And as for Pangaea, I can only compare it to the legends of the lost continent of Atlantis!

That's nice. We can, however, determine that lattitude at which igneous rocks formed - essentially by looking at the allignment of diamagnetic molecules within the rocks. When we look at rocks from around the world, we find that all rocks dated at around 250 million years ago formed around the equator. We can also look at things like correlation of terrestrial species (e.g. the same species can be found in the fossil records in South America and Africa around 250 million years ago, and then begin to diverge), the extent of glaciation at this time in the Southern Hemisphere, or even the rate at which the continents are moving currently (see Marnix's post). We can also look at the distribution and age of volcanic islands and seamounts, e.g. the Hawaiian Island chain and the Emperor Seamounts.

If you don't know what I'm talking about, then you haven't done so much as a simple google search.

Oh thank you drowsy turtle for being so clear with us! You state the following:

The Mantle is largely solid.

So the Earth's Mantle is "largely" solid, meaning most of it is solid and just a little here and there is perhaps `slightly' liquid. I tell you if Basil Fawlty ever took up geology you two would get on just fine.

And again you make yourself quite clear on the temperature of the Earth's core:

I could guestimate, but I couldn't give you an exact figure. It most likely ranges between 4000-8000k, obviously being hotter towards the centre.

Okay, so that easily rivals the surface temperature of the Sun!

And then you said the following on Pangaea:

That's nice. We can, however, determine that lattitude at which igneous rocks formed - essentially by looking at the allignment of diamagnetic molecules within the rocks. When we look at rocks from around the world, we find that all rocks dated at around 250 million years ago formed around the equator.

And can I ask how many times the Earth's poles have shifted and reversed over that time?

We can also look at things like correlation of terrestrial species (e.g. the same species can be found in the fossil records in South America and Africa around 250 million years ago, and then begin to diverge), the extent of glaciation at this time in the Southern Hemisphere, or even the rate at which the continents are moving currently (see Marnix's post).

But what about all the numerous land bridges that you have so conveniently forgotten about drowsy turtle? Animal species could easily have crossed these bridges which then subsequently sunk with rising sea levels.

We can also look at the distribution and age of volcanic islands and seamounts, e.g. the Hawaiian Island chain and the Emperor Seamounts.

What? I couldn't follow you with this one at all.

Originally Posted by drowsy turtle

Originally Posted by galexander

I refuse to accept that we are floating around on a sea of lava.

That's handy, because we're not. The Mantle is largely solid. We know this because S-waves pass through it.

Originally Posted by galexander

I mean would anyone care to tell me exactly how hot the Earth's core is said to be?

I could guestimate, but I couldn't give you an exact figure. It most likely ranges between 4000-8000k, obviously being hotter towards the centre.

Originally Posted by galexander

And as for Pangaea, I can only compare it to the legends of the lost continent of Atlantis!

That's nice. We can, however, determine that lattitude at which igneous rocks formed - essentially by looking at the allignment of diamagnetic molecules within the rocks. When we look at rocks from around the world, we find that all rocks dated at around 250 million years ago formed around the equator. We can also look at things like correlation of terrestrial species (e.g. the same species can be found in the fossil records in South America and Africa around 250 million years ago, and then begin to diverge), the extent of glaciation at this time in the Southern Hemisphere, or even the rate at which the continents are moving currently (see Marnix's post). We can also look at the distribution and age of volcanic islands and seamounts, e.g. the Hawaiian Island chain and the Emperor Seamounts.

If you don't know what I'm talking about, then you haven't done so much as a simple google search.

Again I return to what drowsy turtle has said on the Earth's inner goings-on. He says this about the temperature of the Earth's core:

Originally Posted by drowsy turtle

It most likely ranges between 4000-8000k, obviously being hotter towards the centre.

The Earth's outer core is said to be comprised of molten iron. Now the melting point of iron at atmospheric pressure is 1536 °C. But what is the melting point of iron at such huge depths and pressures towards the Earth's core? The outer core extends from 2,900 to 4,700 km in depth. Think of the weight of the rock above this bearing down. What pressures must this 'molten' iron be under?

At such phenomenal pressures the melting point of iron would just sky rocket.

Again even though drowsy turtle says this about the Earth's mantle:

Originally Posted by drowsy turtle

The Mantle is largely solid.

For continental drift to occur there needs to be 'convective currents' beneath the Earth's crust which cause the drift to occur. At least this is the theory.

The asthenosphere, which lies at a depth of 100 to 200 km, is said to be viscous and plastic and therefore supplies the convective currents needed to support the theory of continental drift.

But consider that rock melts at around 1,200°C at atmospheric pressure and at a depth of over 100 km the melting point of course would be far higher than this because of the pressures involved. So if the Earth is well over 1,200°C at 100 km in depth, how hot is it going to be at 6,370 km at its very centre. Just do the maths!

Assuming that the temperature increase is linear with depth and at the surface the temp. is 20°C, that gives a differential of 1,180°C for every 100 km depth increase. This would then give you a temperature at the Earth's centre of 75,166°C!!!!

But in reality it would be much, much worse than this as it would not be a linear increase with depth. It would be even hotter still!

But let us look again more closely at the asthenosphere. Of course it isn't really lava at all, it is extremely viscous and plastic. This is because it is almost on the verge of fusion. But how could it be on the verge of fusion over the entire 100 km of its depth? As you went down through such a depth the pressure would increase significantly actually changing the melting point of the rock. So if the top layer were viscous, the layers below would all be solid.

And how do you get convective currents in extremely viscous, plastic rock? Conduction of heat would completely cancel out any tendancy for convection to occur.

In my opinion the entire model of the Earth's inner workings with regard to continental drift completely breaks down and ends up looking like something from out of a Jules Verne novel!

Originally Posted by galexander

Oh thank you drowsy turtle for being so clear with us! You state the following:

The Mantle is largely solid.

So the Earth's Mantle is "largely" solid, meaning most of it is solid and just a little here and there is perhaps `slightly' liquid. I tell you if Basil Fawlty ever took up geology you two would get on just fine.

I say 'largely' solid because, given how you have twisted my words in the past, I thoroughly expected you to do a google search to discover the existance of a small amount of liquid magma in the Asthenosphere, corresponding to the low-velocity zone.

Originally Posted by galexander

And then you said the following on Pangaea:

That's nice. We can, however, determine that lattitude at which igneous rocks formed - essentially by looking at the allignment of diamagnetic molecules within the rocks. When we look at rocks from around the world, we find that all rocks dated at around 250 million years ago formed around the equator.

And can I ask how many times the Earth's poles have shifted and reversed over that time?

You can google it yourself and find out. It's not a figure that I have memorised. It doesn't affect the validity of these results, because you still get the same lattitude - you just measure it as North instead of South. Of course, these measurements are corrected for the polarity of the magnetic field for use in modeling, but even if all we had was the raw data, we could still clearly see where a landmass is moving to a higher or lower lattitude.

Originally Posted by galexander

But what about all the numerous land bridges that you have so conveniently forgotten about drowsy turtle? Animal species could easily have crossed these bridges which then subsequently sunk with rising sea levels.

Land bridges across the Atlantic are, at best, a myth and at worst a complete joke. It got to the point where there were so many land bridges necessary to explain the distribution of animal species that there was barely any Atlantic left.

It is also worth noting that sea level was no more than 30-40 metres lower at the end of the Permian than it is today, while the Atlantic is several kilometres deep.

Originally Posted by galexander

We can also look at the distribution and age of volcanic islands and seamounts, e.g. the Hawaiian Island chain and the Emperor Seamounts.

What? I couldn't follow you with this one at all.

The Hawaiian island chain is directly above a hotspot, where magma rises to the surface and erupts to form volcanic islands. The island chain actually extends thousands of kilometres to the North-West, with the age of the rocks increasing away from the currently active volcanoes on Hawaii, showing how the plate has moved throughout time, while the hotspot has remained stationary.

Again, all you had to do was a simpel google search:

Originally Posted by galexander

Again I return to what drowsy turtle has said on the Earth's inner goings-on. He says this about the temperature of the Earth's core:

Originally Posted by drowsy turtle

It most likely ranges between 4000-8000k, obviously being hotter towards the centre.

The Earth's outer core is said to be comprised of molten iron. Now the melting point of iron at atmospheric pressure is 1536 °C. But what is the melting point of iron at such huge depths and pressures towards the Earth's core? The outer core extends from 2,900 to 4,700 km in depth. Think of the weight of the rock above this bearing down. What pressures must this 'molten' iron be under?

At such phenomenal pressures the melting point of iron would just sky rocket.[/quote]

Hence, we can approximate the temperature of the outer core from the fact that it is liquid.

Originally Posted by galexander

Again even though drowsy turtle says this about the Earth's mantle:

Originally Posted by drowsy turtle

The Mantle is largely solid.

For continental drift to occur there needs to be 'convective currents' beneath the Earth's crust which cause the drift to occur. At least this is the theory.

You're right, the mantle is thought to convect (although this is no longer thought to be a major cause for plate movement; slab-pull and uplift pressure tend to be favoured). The mantle convects very slowly, over millions of years, because it is solid.

If you fail to imagine how this might occur, consider this; pressure and stress in the crust cause huge areas of brittle rock to fold, often into elongated 'S' shapes. This can happen because if the rate of strain is very small, the rocks act plastically and deform rather than fracture.

Originally Posted by galexander

But consider that rock melts at around 1,200°C at atmospheric pressure and at a depth of over 100 km the melting point of course would be far higher than this because of the pressures involved. So if the Earth is well over 1,200°C at 100 km in depth, how hot is it going to be at 6,370 km at its very centre. Just do the maths!

You falsely assume a constant geothermal gradient. Why?

And as I said, the mantle is, for the most part, made of rocks in the solid state.

Originally Posted by galexander

But in reality it would be much, much worse than this as it would not be a linear increase with depth. It would be even hotter still!

Or colder, depensing on how you choose to draw your curve. You're not basing any of these guesses on any empirical reasoning, you're making random guesses.

Originally Posted by galexander

But let us look again more closely at the asthenosphere. Of course it isn't really lava at all, it is extremely viscous and plastic. This is because it is almost on the verge of fusion. But how could it be on the verge of fusion over the entire 100 km of its depth? As you went down through such a depth the pressure would increase significantly actually changing the melting point of the rock. So if the top layer were viscous, the layers below would all be solid.

As you just stated, the pressure and temperature both increase with depth.

Originally Posted by galexander

And how do you get convective currents in extremely viscous, plastic rock?

Over a very long time.

A graph showing the geothermal gradient in the crust/mantle:



Notice how the trend in the lithosphere is not continuous into the rest of the mantle. The lithosphere is the thin layer on the surface which is rapidly cooled by convection of air/water at the surface, and by direct radiation of heat. This is why the thermal gradient through the lithosphere is greater.

Originally Posted by drowsy turtle

Originally Posted by galexander

Oh thank you drowsy turtle for being so clear with us! You state the following:

The Mantle is largely solid.

So the Earth's Mantle is "largely" solid, meaning most of it is solid and just a little here and there is perhaps `slightly' liquid. I tell you if Basil Fawlty ever took up geology you two would get on just fine.

I say 'largely' solid because, given how you have twisted my words in the past, I thoroughly expected you to do a google search to discover the existance of a small amount of liquid magma in the Asthenosphere, corresponding to the low-velocity zone.

Originally Posted by galexander

And then you said the following on Pangaea:

That's nice. We can, however, determine that lattitude at which igneous rocks formed - essentially by looking at the allignment of diamagnetic molecules within the rocks. When we look at rocks from around the world, we find that all rocks dated at around 250 million years ago formed around the equator.

And can I ask how many times the Earth's poles have shifted and reversed over that time?

You can google it yourself and find out. It's not a figure that I have memorised. It doesn't affect the validity of these results, because you still get the same lattitude - you just measure it as North instead of South. Of course, these measurements are corrected for the polarity of the magnetic field for use in modeling, but even if all we had was the raw data, we could still clearly see where a landmass is moving to a higher or lower lattitude.

Originally Posted by galexander

But what about all the numerous land bridges that you have so conveniently forgotten about drowsy turtle? Animal species could easily have crossed these bridges which then subsequently sunk with rising sea levels.

Land bridges across the Atlantic are, at best, a myth and at worst a complete joke. It got to the point where there were so many land bridges necessary to explain the distribution of animal species that there was barely any Atlantic left.

It is also worth noting that sea level was no more than 30-40 metres lower at the end of the Permian than it is today, while the Atlantic is several kilometres deep.

Originally Posted by galexander

We can also look at the distribution and age of volcanic islands and seamounts, e.g. the Hawaiian Island chain and the Emperor Seamounts.

What? I couldn't follow you with this one at all.

The Hawaiian island chain is directly above a hotspot, where magma rises to the surface and erupts to form volcanic islands. The island chain actually extends thousands of kilometres to the North-West, with the age of the rocks increasing away from the currently active volcanoes on Hawaii, showing how the plate has moved throughout time, while the hotspot has remained stationary.

Originally Posted by drowsy turtle

Land bridges across the Atlantic are, at best, a myth and at worst a complete joke. It got to the point where there were so many land bridges necessary to explain the distribution of animal species that there was barely any Atlantic left.

Oh come on drowsy turtle, what about the land bridge across the Bering Strait?

Any prehistoric creature, including prehistoric man, could easily have crossed from Asia then into North and South America. And there was even a land bridge from mainland Europe into Britain.

And in addition to those two land bridges there were countless others.

Why therefore did you even mention a land bridge across the Atlantic? You don't need one.

drowsy turtle said the following:

Originally Posted by drowsy turtle

You're right, the mantle is thought to convect (although this is no longer thought to be a major cause for plate movement; slab-pull and uplift pressure tend to be favoured). The mantle convects very slowly, over millions of years, because it is solid.

If you fail to imagine how this might occur, consider this; pressure and stress in the crust cause huge areas of brittle rock to fold, often into elongated 'S' shapes. This can happen because if the rate of strain is very small, the rocks act plastically and deform rather than fracture.

Well that, practically, is exactly how I picture plate tectonics. Only you don't get any continental drift at all in my books.

As the Earth's interior very gradually cools and contracts the mantle is bound to buckle and fold producing fault lines and mountain ranges.

Earthquakes along these fault lines have the same energy as atomic explosions and this same energy when concentrated can melt rock producing volcanic activity.

You don't need a high interior temperature for the Earth at all.

Originally Posted by galexander

Oh come on drowsy turtle, what about the land bridge across the Bering Strait?

Any prehistoric creature, including prehistoric man, could easily have crossed from Asia then into North and South America. And there was even a land bridge from mainland Europe into Britain.

You are talking about areas where there are recent shallow seas seperating countries/continents. I am talking about species distributed in both Western Africa and South America during the same time period - any 'land bridge' linking these populations would have to cross the Atlantic.

I assumed that you were addressing my point with the largely defunct hypothesis from the 50s and 60s that the Atlantic was crossed by land bridges which allowed animals to cross. If you were not, then my apologies - but I would question why the existance of shallow water between land masses elsewhere in the world is strictly relevant.

I was referring to distributions such as the ones in this image:

Originally Posted by drowsy turtle

Originally Posted by galexander

Oh come on drowsy turtle, what about the land bridge across the Bering Strait?

Any prehistoric creature, including prehistoric man, could easily have crossed from Asia then into North and South America. And there was even a land bridge from mainland Europe into Britain.

You are talking about areas where there are recent shallow seas seperating countries/continents. I am talking about species distributed in both Western Africa and South America during the same time period - any 'land bridge' linking these populations would have to cross the Atlantic.

I assumed that you were addressing my point with the largely defunct hypothesis from the 50s and 60s that the Atlantic was crossed by land bridges which allowed animals to cross. If you were not, then my apologies - but I would question why the existance of shallow water between land masses elsewhere in the world is strictly relevant.

I was referring to distributions such as the ones in this image:

There were land bridges from Africa into Europe. And from Europe, Asia can be entered. And from Asia across the Bering Strait land bridge into North America. And from North America into South America.

Next you'll be telling me prehistoric creatures couldn't have walked that far!

Come on drowsy turtle, put your thinking cap on.

Originally Posted by galexander

Well that, practically, is exactly how I picture plate tectonics. Only you don't get any continental drift at all in my books.

As the Earth's interior very gradually cools and contracts the mantle is bound to buckle and fold producing fault lines and mountain ranges.

Not a bad hypothesis, I suppose, if the only evidence you had to make a guess from were the existance of mountains and faults. But your hypothesis cannot explain the directly observable motion of the continents, nor the distribution of palaeozoic species (as in the above post), nor the existance of benioff zones, nor the varying petrology and crustal thickness between the continents and the oceans, nor features such as intraplate volcanoes, nor the palaeo-lattitudes of various land masses (the rocks making up the UK were at an equatorial lattitude 200 million years ago), nor the extent of glaciation from the Southern side of various continents, nor the palaeomagnetic stripes seen around spreading ridges, nor the increasing age of basalts away from spreadign ridges.

Will you accept that your hypothesis cannot explain any of these pieces of evidence (and in fact that many of them actively refute your hypothesis), or will you pretend I didn't say any of this?

Originally Posted by galexander

You don't need a high interior temperature for the Earth at all.

Yes we do, because as I explained before, we know that the outer core is liquid because it doesn't transmit S-waves. Given the pressure at this depth, which we can approximately work out by determining the S-wave velocity in the overlaying material, we can approximately determine the minimum temperature of the outer core. And by doing this, we find that the outer core must be at least 4400 celcius or so.

We also know that the core must be hot from models for accretion, from the very existance of a geothermal gradient in the lithosphere (i.e. why would heat be escaping the core unless it was significantly hotter there; such a heat flow without a hot core would violate the second law of thermodynamics), etc.

Originally Posted by galexander

There were land bridges from Africa into Europe. And from Europe, Asia can be entered. And from Asia across the Bering Strait land bridge into North America. And from North America into South America.

Mesosaurus (an example form the diagram) isn't found in Asia, Europe or North America. It occurs fairly commonly in a small area covering the Southern parts of Africa and South America.

As a freshwater reptile, Mesosaurus would have been very sensative to changes in climate; for instance, crossing central Africa (in its present-day location) when global temperatures were several degrees hotter would be completely out of the question.

It's the same reason we don't see organisms living in the Sahara in Siberia; while the Sahara is technically linked with Siberia by land, none of the animals would be able to survive there, or in any of the places between, without first evolving to suit the climate - and so would no longer be the same species as the animals that continued to dwell in the desert.

And glossopteris, being a plant, certainly couldn't walk that far.

Lastly, do remember that these species are just a small number of examples; there are many more.

Originally Posted by galexander

Only you don't get any continental drift at all in my books.

Which books are those, precisely?

It's an idiom. He means in his opinion.

Originally Posted by drowsy turtle

It's an idiom. He means in his opinion.

I know that, but my question was meant in the sense that I wonder where galexander is getting his ideas.

Originally Posted by jsloan

Originally Posted by drowsy turtle

It's an idiom. He means in his opinion.

I know that, but my question was meant in the sense that I wonder where galexander is getting his ideas.

My thinking is entirely my own jsloan, however I respect the fact that others may have similar opinions.

Originally Posted by drowsy turtle

Originally Posted by galexander

There were land bridges from Africa into Europe. And from Europe, Asia can be entered. And from Asia across the Bering Strait land bridge into North America. And from North America into South America.

Mesosaurus (an example form the diagram) isn't found in Asia, Europe or North America. It occurs fairly commonly in a small area covering the Southern parts of Africa and South America.

As a freshwater reptile, Mesosaurus would have been very sensative to changes in climate; for instance, crossing central Africa (in its present-day location) when global temperatures were several degrees hotter would be completely out of the question.

It's the same reason we don't see organisms living in the Sahara in Siberia; while the Sahara is technically linked with Siberia by land, none of the animals would be able to survive there, or in any of the places between, without first evolving to suit the climate - and so would no longer be the same species as the animals that continued to dwell in the desert.

And glossopteris, being a plant, certainly couldn't walk that far.

Lastly, do remember that these species are just a small number of examples; there are many more.

And how do they know Mesosaurus was so sensitive to the cold?

Just because palaeontologists have only found its remains in these two locations to date does not therefore mean that they will never find them elsewhere. Unsafe in my opinion.

Besides in warmer times it could easily have migrated out of Africa and what was there to have stopped it doing this?

Originally Posted by drowsy turtle

And glossopteris, being a plant, certainly couldn't walk that far.

Presumably this was an attempt at humour. Ever heard of seed propagation by air, water or animal spore?






This is the map on Wiki which supposedly prooves that the land masses were joined and shows the extent of glossopteris' propagation. But why the hole in the middle? Presumably it was too warm or too cold there?

Originally Posted by drowsy turtle

A graph showing the geothermal gradient in the crust/mantle:



Notice how the trend in the lithosphere is not continuous into the rest of the mantle. The lithosphere is the thin layer on the surface which is rapidly cooled by convection of air/water at the surface, and by direct radiation of heat. This is why the thermal gradient through the lithosphere is greater.

According to my understanding of physics the hotter an object is the quicker it loses heat. However your graph would suggest that the hotter an object is the slower it loses heat.

Such a graph is highly convenient for advocates of continental drift but it goes against the known laws of physics.

And you have still not answered my question as to how hot it would be at the top of the Asthenosphere, 100 km down?

If rock typically melts at 1,200C at one atmosphere pressure, what is the pressure under 100 km of rock?

Originally Posted by drowsy turtle

Originally Posted by galexander

Oh come on drowsy turtle, what about the land bridge across the Bering Strait?

Any prehistoric creature, including prehistoric man, could easily have crossed from Asia then into North and South America. And there was even a land bridge from mainland Europe into Britain.

You are talking about areas where there are recent shallow seas seperating countries/continents. I am talking about species distributed in both Western Africa and South America during the same time period - any 'land bridge' linking these populations would have to cross the Atlantic.

I assumed that you were addressing my point with the largely defunct hypothesis from the 50s and 60s that the Atlantic was crossed by land bridges which allowed animals to cross. If you were not, then my apologies - but I would question why the existance of shallow water between land masses elsewhere in the world is strictly relevant.

I was referring to distributions such as the ones in this image:

I'd like to query this map I quote above.

Why exactly are these creatures living in such narrow bands? Looks slightly suspicious to me.

And the area shown as inhabited by glossopteris is quite different from the map I produced detailed below. Have a closer look. It's completely inconsistent.

Is this just Wikipaedia playing up again or the science is doddery?

Originally Posted by galexander

And how do they know Mesosaurus was so sensitive to the cold?

Because it was a reptile - and an aquatic reptile at that. Have you ever considered why we don't get crocodiles in the UK?

Originally Posted by galexander

Just because palaeontologists have only found its remains in these two locations to date does not therefore mean that they will never find them elsewhere. Unsafe in my opinion.

It would be more unsafe to assume that a species was abundant across the globe simply because it is found in 2 different places with a fairly good abundance.

Originally Posted by galexander

Besides in warmer times it could easily have migrated out of Africa and what was there to have stopped it doing this?

I'm going to stop here, and declare that the burden of evidence is with you. If you are claiming that mesosaurus, and other permian/triassic animals, migrated from Africa to South America via the Beiring Strait, then you can support this claim. For instance, citing life assemblages in Europe and Asia of the species would be a start.

Originally Posted by galexander

Originally Posted by drowsy turtle

And glossopteris, being a plant, certainly couldn't walk that far.

Presumably this was an attempt at humour.

Indeed.

Originally Posted by galexander

This is the map on Wiki which supposedly prooves that the land masses were joined and shows the extent of glossopteris' propagation. But why the hole in the middle? Presumably it was too warm or too cold there?

More likely, the current extent of land ice and glaciers makes it too difficult to gather much data on the fossil record of Antarctica. Or possibly it is impossible to know because there are no rocks preserved from this period. Or any one of many other explanations.

Originally Posted by galexander

According to my understanding of physics the hotter an object is the quicker it loses heat.

How hot it is is irrelevant. If you place a lump of metal at 50 degrees into water also at 50 degrees, it will not lose heat at all. Place the same lump of metal into water at 5 degrees, and it will lose heat very quickly.

Originally Posted by galexander

However your graph would suggest that the hotter an object is the slower it loses heat.

How so? All the graph shows is that there is a non-linear change in temperature away from the core.

Originally Posted by galexander

Such a graph is highly convenient for advocates of continental drift but it goes against the known laws of physics.

As I said, we know the outer core is molten. And as I said above, it doesn't violate any laws of physics - there is heat flowing from the hot core to the cold crust, and the crust remains cold because heat is radiated into space.

You would also do well to consider that rock is a fairly good thermal insulator.

Originally Posted by galexander

And you have still not answered my question as to how hot it would be at the top of the Asthenosphere, 100 km down?

I don't recall you asking that question, but probably around 1000-1500 degrees celcius or so.

Originally Posted by galexander

If rock typically melts at 1,200C at one atmosphere pressure, what is the pressure under 100 km of rock?

If we assume the lithosphere has a constant density of 3.3g/cm^3, and we assume that g=9.8 throughout the lithosphere, the pressure would be about 3.2GPa.

Compare this to the phase diagram for the upper mantle:



Hey presto, we see that the rocks should be in the solid phase.

Still awaiting your reply:

Originally Posted by drowsy turtle

But your hypothesis cannot explain the directly observable motion of the continents, nor the distribution of palaeozoic species (as in the above post), nor the existance of benioff zones, nor the varying petrology and crustal thickness between the continents and the oceans, nor features such as intraplate volcanoes, nor the palaeo-lattitudes of various land masses (the rocks making up the UK were at an equatorial lattitude 200 million years ago), nor the extent of glaciation from the Southern side of various continents, nor the palaeomagnetic stripes seen around spreading ridges, nor the increasing age of basalts away from spreadign ridges.

Will you accept that your hypothesis cannot explain any of these pieces of evidence (and in fact that many of them actively refute your hypothesis), or will you pretend I didn't say any of this?

Originally Posted by galexander

You don't need a high interior temperature for the Earth at all.

Yes we do, because as I explained before, we know that the outer core is liquid because it doesn't transmit S-waves. Given the pressure at this depth, which we can approximately work out by determining the S-wave velocity in the overlaying material, we can approximately determine the minimum temperature of the outer core. And by doing this, we find that the outer core must be at least 4400 celcius or so.

We also know that the core must be hot from models for accretion, from the very existance of a geothermal gradient in the lithosphere (i.e. why would heat be escaping the core unless it was significantly hotter there; such a heat flow without a hot core would violate the second law of thermodynamics), etc.

Originally Posted by drowsy turtle

Originally Posted by galexander

And how do they know Mesosaurus was so sensitive to the cold?

Because it was a reptile - and an aquatic reptile at that. Have you ever considered why we don't get crocodiles in the UK?

Originally Posted by galexander

Just because palaeontologists have only found its remains in these two locations to date does not therefore mean that they will never find them elsewhere. Unsafe in my opinion.

It would be more unsafe to assume that a species was abundant across the globe simply because it is found in 2 different places with a fairly good abundance.

Originally Posted by galexander

Besides in warmer times it could easily have migrated out of Africa and what was there to have stopped it doing this?

I'm going to stop here, and declare that the burden of evidence is with you. If you are claiming that mesosaurus, and other permian/triassic animals, migrated from Africa to South America via the Beiring Strait, then you can support this claim. For instance, citing life assemblages in Europe and Asia of the species would be a start.

Originally Posted by galexander

Originally Posted by drowsy turtle

And glossopteris, being a plant, certainly couldn't walk that far.

Presumably this was an attempt at humour.

Indeed.

Originally Posted by galexander

This is the map on Wiki which supposedly prooves that the land masses were joined and shows the extent of glossopteris' propagation. But why the hole in the middle? Presumably it was too warm or too cold there?

More likely, the current extent of land ice and glaciers makes it too difficult to gather much data on the fossil record of Antarctica. Or possibly it is impossible to know because there are no rocks preserved from this period. Or any one of many other explanations.

drowsy turtle said the following:

Originally Posted by drowsy turtle

Because it was a reptile - and an aquatic reptile at that. Have you ever considered why we don't get crocodiles in the UK?

Yes we don't now but we used to. There are fossil crocodiles, monkeys, tigers and rhino's in the UK. The Bering Strait is a little further north of the UK but during the summer months tropical creatures could easily have crossed this land bridge without getting too chilly.

Originally Posted by drowsy turtle

Originally Posted by galexander

According to my understanding of physics the hotter an object is the quicker it loses heat.

How hot it is is irrelevant. If you place a lump of metal at 50 degrees into water also at 50 degrees, it will not lose heat at all. Place the same lump of metal into water at 5 degrees, and it will lose heat very quickly.

Originally Posted by galexander

However your graph would suggest that the hotter an object is the slower it loses heat.

How so? All the graph shows is that there is a non-linear change in temperature away from the core.

Originally Posted by galexander

Such a graph is highly convenient for advocates of continental drift but it goes against the known laws of physics.

As I said, we know the outer core is molten. And as I said above, it doesn't violate any laws of physics - there is heat flowing from the hot core to the cold crust, and the crust remains cold because heat is radiated into space.

You would also do well to consider that rock is a fairly good thermal insulator.

Originally Posted by galexander

And you have still not answered my question as to how hot it would be at the top of the Asthenosphere, 100 km down?

I don't recall you asking that question, but probably around 1000-1500 degrees celcius or so.

Originally Posted by galexander

If rock typically melts at 1,200C at one atmosphere pressure, what is the pressure under 100 km of rock?

If we assume the lithosphere has a constant density of 3.3g/cm^3, and we assume that g=9.8 throughout the lithosphere, the pressure would be about 3.2GPa.

Compare this to the phase diagram for the upper mantle:



Hey presto, we see that the rocks should be in the solid phase.

drowsy turtle said the following:

Originally Posted by drowsy turtle

Hey presto, we see that the rocks should be in the solid phase.

So if the Earth's mantle is entirely solid and no liquid (if I understand you correctly that is) then without convective currents how do get continental drift?

solid materials still can deform, in what is known as creep

when deformed quickly, solid materials fracture in a brittle fashion, however, under slow deformation they "flow" after a fashion - think tarmac on a hot day

this type of behaviour can be observed when the material is exposed to temperatures in excess of its recrystallisation temperature, which are typically (if i remember it correctly) about 0.4 times its melting point

Originally Posted by marnixR

solid materials still can deform, in what is known as creep

when deformed quickly, solid materials fracture in a brittle fashion, however, under slow deformation they "flow" after a fashion - think tarmac on a hot day

this type of behaviour can be observed when the material is exposed to temperatures in excess of its recrystallisation temperature, which are typically (if i remember it correctly) about 0.4 times its melting point

Okay marnixR, I don't deny that rock can deform under very intense pressures and so therefore, in a way at least, behaves somewhat like a liquid.

But are you seriously suggesting that such a process can support convective currents?

is there anything in the physics of convection that sets a minimum speed to it ? remember, sea floors spread at speeds in the order of 5mm per year - i don't know how this translates into required convection speeds, but i doubt whether it's anything beyond what's physically possible in dense hot rock under pressure

after all, hot spots and magma chambers are fed through a similar rising of hot material through the earth's mantle

Originally Posted by galexander

Yes we don't now but we used to. There are fossil crocodiles, monkeys, tigers and rhino's in the UK. The Bering Strait is a little further north of the UK but during the summer months tropical creatures could easily have crossed this land bridge without getting too chilly.

Except we can show by paleomagnetic evidence that the UK was at/near the equator at this time.

Originally Posted by galexander

So if the Earth's mantle is entirely solid and no liquid (if I understand you correctly that is) then without convective currents how do get continental drift?

I have already explained this, but what the hell, another time can't hurt:

a) The mantle does convect, dispite being solid. Under the right conditions, solids can act plastically and convect; for instance, consider chewing gum. Chewing gum is undeniably a solid, and yet it is easily distorted in countless ways. Why should it be more tricky for a solid to convect than for it to bend and fold?

b) Mantle convection is not really considered a major contributer to plate movement any more. Mantle pressure and (especially) slab pull tend to be the preferred mechanisms.


This is, by the way, a case where you could do a google search instead of post questions.

Are you actually going to bother addressing or aknowledging points that you cannot counter?

Originally Posted by drowsy turtle

Still awaiting your reply:

Originally Posted by drowsy turtle

But your hypothesis cannot explain the directly observable motion of the continents, nor the distribution of palaeozoic species (as in the above post), nor the existance of benioff zones, nor the varying petrology and crustal thickness between the continents and the oceans, nor features such as intraplate volcanoes, nor the palaeo-lattitudes of various land masses (the rocks making up the UK were at an equatorial lattitude 200 million years ago), nor the extent of glaciation from the Southern side of various continents, nor the palaeomagnetic stripes seen around spreading ridges, nor the increasing age of basalts away from spreadign ridges.

Will you accept that your hypothesis cannot explain any of these pieces of evidence (and in fact that many of them actively refute your hypothesis), or will you pretend I didn't say any of this?

Originally Posted by galexander

You don't need a high interior temperature for the Earth at all.

Yes we do, because as I explained before, we know that the outer core is liquid because it doesn't transmit S-waves. Given the pressure at this depth, which we can approximately work out by determining the S-wave velocity in the overlaying material, we can approximately determine the minimum temperature of the outer core. And by doing this, we find that the outer core must be at least 4400 celcius or so.

We also know that the core must be hot from models for accretion, from the very existance of a geothermal gradient in the lithosphere (i.e. why would heat be escaping the core unless it was significantly hotter there; such a heat flow without a hot core would violate the second law of thermodynamics), etc.

Originally Posted by galexander

Ophiolite are you telling us that gravel erodes from out of rocks just as sand does?.

Certainly. If you had done any field work or read any relevant research papers you would know this to be the case.

Originally Posted by galexander

To be absolutely honest I found your carefully constructed piece on sand formation unconvincing and at best hairsplitting.

So you are rejecting the findings of thousands of geologists and geomorphologists in favour of your own delusional musings? Get real.

Originally Posted by galexander

I mean what evidence have you seriously presented? I couldn't see any!

I believe you. You really couldn't see any evidence. This is because you are a delusional fool and not worth the effort of conversing with.

Originally Posted by drowsy turtle

Originally Posted by galexander

Yes we don't now but we used to. There are fossil crocodiles, monkeys, tigers and rhino's in the UK. The Bering Strait is a little further north of the UK but during the summer months tropical creatures could easily have crossed this land bridge without getting too chilly.

Except we can show by paleomagnetic evidence that the UK was at/near the equator at this time.

Originally Posted by galexander

So if the Earth's mantle is entirely solid and no liquid (if I understand you correctly that is) then without convective currents how do get continental drift?

I have already explained this, but what the hell, another time can't hurt:

a) The mantle does convect, dispite being solid. Under the right conditions, solids can act plastically and convect; for instance, consider chewing gum. Chewing gum is undeniably a solid, and yet it is easily distorted in countless ways. Why should it be more tricky for a solid to convect than for it to bend and fold?

b) Mantle convection is not really considered a major contributer to plate movement any more. Mantle pressure and (especially) slab pull tend to be the preferred mechanisms.


This is, by the way, a case where you could do a google search instead of post questions.

Take a look at this webpage. Alligators found at 80 degrees north:

http://creation.com/climate-models-fail

And a fossil crocodile skull was found in Siberia:

http://en.wikipedia.org/wiki/Kyasuchus

Originally Posted by drowsy turtle

Originally Posted by galexander

Yes we don't now but we used to. There are fossil crocodiles, monkeys, tigers and rhino's in the UK. The Bering Strait is a little further north of the UK but during the summer months tropical creatures could easily have crossed this land bridge without getting too chilly.

Except we can show by paleomagnetic evidence that the UK was at/near the equator at this time.

Originally Posted by galexander

So if the Earth's mantle is entirely solid and no liquid (if I understand you correctly that is) then without convective currents how do get continental drift?

I have already explained this, but what the hell, another time can't hurt:

a) The mantle does convect, dispite being solid. Under the right conditions, solids can act plastically and convect; for instance, consider chewing gum. Chewing gum is undeniably a solid, and yet it is easily distorted in countless ways. Why should it be more tricky for a solid to convect than for it to bend and fold?

b) Mantle convection is not really considered a major contributer to plate movement any more. Mantle pressure and (especially) slab pull tend to be the preferred mechanisms.


This is, by the way, a case where you could do a google search instead of post questions.

If hot rock rises (very, very, very slowly), then presumably the cold rock must descend.

But this is laughable. The differences in densities between the rock concerned would be minute and would not produce the huge forces necessary to deform rock.

And even if there were convective currents within solid rock the convective currents would tend to be too small and chaotic to move an entire continent over thousands and thousands of miles in the exact same direction. The convective cells would tend to work against each other and would tend to break a continent like Asia up into smaller islands.

The convective cells you are proposing travel horizontally underneath the Earth's crust in parallel lines over many thousands of miles.

The whole thing is just ridiculous.

Originally Posted by galexander

http://creation.com/climate-models-fail

i see - true colours finally revealed
are you sure there's no agenda ?

Originally Posted by galexander

Take a look at this webpage. Alligators found at 80 degrees north:

http://creation.com/climate-models-fail

And a fossil crocodile skull was found in Siberia:

http://en.wikipedia.org/wiki/Kyasuchus

Excellent. And what was the lattitude when the sediment they are found in was deposited? (I'm not going to bother following up the links. On an issue where the whole of the scientific community disagrees with you, pages on creation.com and wikipedia aren't really worth reading.)

Interesting that you would cite a website that has a 'Young Earth' agenda, while trying to explain an old Earth without plate tectonics...

Why is it that you think that in the Permian all species were distributed all over the world, and yet today they are not? I'm not being obtuse, I'm generally interested by your inconsistent uniformitarianist approach to such things.

Originally Posted by galexander

If hot rock rises (very, very, very slowly), then presumably the cold rock must descend.

This is what 'convection' means, yes.

Originally Posted by galexander

But this is laughable.

Why? And why should the fact that it is laughable be an obstacle in beliving it? Heliocentricity was laughable once...

Originally Posted by galexander

The differences in densities between the rock concerned would be minute and would not produce the huge forces necessary to deform rock.

The difference in density is vast, hence the variation in velocities of seismic waves through the mantle.

Originally Posted by galexander

And even if there were convective currents within solid rock the convective currents would tend to be too small and chaotic to move an entire continent over thousands and thousands of miles in the exact same direction.

What makes you say this? As viscosity increases, convection actually tends to occur on larger and larger scales, because the individual atoms/molecules cannot move as freely.

Originally Posted by galexander

The convective cells would tend to work against each other and would tend to break a continent like Asia up into smaller islands.

Again, this is simply an assertion. And, as I've told you twice now, mantle convection is no longer considered a major mechanism in plate movement.

Originally Posted by galexander

The convective cells you are proposing travel horizontally underneath the Earth's crust in parallel lines over many thousands of miles.

Do they? Why do you say that?

Originally Posted by galexander

The whole thing is just ridiculous.

Why? Because you keep repeating that it is? If it's as ridiculous as you seem to think, show me your calculations? Show me the actual physical evidence that causes you to dispute the accepted models for mantle convection?



And then, can you explain the relevance of this to continental drift? Because mantle convection was originally suggested as a mechanism to explain the observable fact that the continents move relative to each other; not the other way around.



Also, you still haven't replied to my ealier post (which I have re-posted twice since). Is this because you can't answer the questions I asked? If so, your hypothesis is worthless - you have nothing but idle speculation and non-specific ridicule on your side.

Good evening to you.

Originally Posted by marnixR

Originally Posted by galexander

http://creation.com/climate-models-fail

i see - true colours finally revealed
are you sure there's no agenda ?

I do not have a hidden agenda and I certainly do not believe the Earth is only 10,000 years old.

Geologists have gone to great efforts to prove that the Earth is far older than just 10,000 years when the science was still very much in its youth. However in the meantime they have come up with a theory that is just as believable as the six day creation story.

Originally Posted by drowsy turtle

Originally Posted by galexander

If hot rock rises (very, very, very slowly), then presumably the cold rock must descend.

This is what 'convection' means, yes.

Originally Posted by galexander

But this is laughable.

Why? And why should the fact that it is laughable be an obstacle in beliving it? Heliocentricity was laughable once...

Originally Posted by galexander

The differences in densities between the rock concerned would be minute and would not produce the huge forces necessary to deform rock.

The difference in density is vast, hence the variation in velocities of seismic waves through the mantle.

Originally Posted by galexander

And even if there were convective currents within solid rock the convective currents would tend to be too small and chaotic to move an entire continent over thousands and thousands of miles in the exact same direction.

What makes you say this? As viscosity increases, convection actually tends to occur on larger and larger scales, because the individual atoms/molecules cannot move as freely.

Originally Posted by galexander

The convective cells would tend to work against each other and would tend to break a continent like Asia up into smaller islands.

Again, this is simply an assertion. And, as I've told you twice now, mantle convection is no longer considered a major mechanism in plate movement.

Originally Posted by galexander

The convective cells you are proposing travel horizontally underneath the Earth's crust in parallel lines over many thousands of miles.

Do they? Why do you say that?

Originally Posted by galexander

The whole thing is just ridiculous.

Why? Because you keep repeating that it is? If it's as ridiculous as you seem to think, show me your calculations? Show me the actual physical evidence that causes you to dispute the accepted models for mantle convection?



And then, can you explain the relevance of this to continental drift? Because mantle convection was originally suggested as a mechanism to explain the observable fact that the continents move relative to each other; not the other way around.



Also, you still haven't replied to my ealier post (which I have re-posted twice since). Is this because you can't answer the questions I asked? If so, your hypothesis is worthless - you have nothing but idle speculation and non-specific ridicule on your side.

Good evening to you.

I found it peculiar that you appear to have completely misunderstood the following:

Originally Posted by galexander

The differences in densities between the rock concerned would be minute and would not produce the huge forces necessary to deform rock.

The difference in density is vast, hence the variation in velocities of seismic waves through the mantle.

I was not referring to seismic wave propagation but the ability of minute density differentials resulting from equally minute temperature differences to deform solid rock.

Lets face it what you are suggesting is the following:

If you were to place a single dried pea on a solid block of rock, over millions of years the pea would slowly sink into the rock creating a hole.

Piffle! Rock only distorts under extremely high stresses.

And secondly how can anyone imagine cold rock descending as you admit above?

Originally Posted by galexander

If hot rock rises (very, very, very slowly), then presumably the cold rock must descend.

This is what 'convection' means, yes.

By the time the cold rock had got anywhere it would already have gained heat via conduction.

Originally Posted by galexander

I found it peculiar that you appear to have completely misunderstood the following:

Originally Posted by galexander

The differences in densities between the rock concerned would be minute and would not produce the huge forces necessary to deform rock.

The difference in density is vast, hence the variation in velocities of seismic waves through the mantle.

I was not referring to seismic wave propagation but the ability of minute density differentials resulting from equally minute temperature differences to deform solid rock.

I believe it is you who misunderstands. The velocity of waves through a material is a function of the density; greater velocities (essentially) relate directly to greater densities.

Originally Posted by galexander

Lets face it what you are suggesting is the following:

If you were to place a single dried pea on a solid block of rock, over millions of years the pea would slowly sink into the rock creating a hole.

Piffle! Rock only distorts under extremely high stresses.

Are you saying that rocks kilometres underground are not under 'high stresses'?

Originally Posted by galexander

And secondly how can anyone imagine cold rock descending as you admit above?

What do you mean? We're not talking about individual blocks of rock moving against each other, we're talking about a single mass of rock undergoing plastic deformation. Imagine, if you will, a circle; as you move one side of the circle upwards by rotating it about the centre of the circle, the other side moves downwards as a result of being attached to the other side of the circle. The principle is essentially the same for convecting mantle; cold rock sinking and hot rock rising are the same process.

Originally Posted by galexander

Originally Posted by galexander

If hot rock rises (very, very, very slowly), then presumably the cold rock must descend.

This is what 'convection' means, yes.

By the time the cold rock had got anywhere it would already have gained heat via conduction.

Peridotite is not a very thermally conductive material. In fact, this is exactly why we do not see rock at 5000 degrees celcius just below the surface; because heat from the core cannot easily reach the surface.

Convection occurs in the mantle for exactly the same reason it occurs in water; because heat flow by conduction is very poor, resulting in the formation of hotter, less-dense regions which rise, while the colder, denser regions sink.





Just to clarify your position; are you suggesting that because you cannot imagine the mantle convecting, continental drift cannot occur?

Lastly, your failure to reply to a number of my previous points show, in my eyes, that you are unable to account for them in your model, therefore showing that your model is deeply flawed. It also shows that you are not willing to concede defeat, which means that you assumed you were correct before reviewing any evidence - which means you are being subjective and unscientific. In fact, you are being arrogant - much like the creationists you do not wish to be associated with (and yet still cite articles from! LOL!).

Originally Posted by galexander

Geologists have gone to great efforts to prove that the Earth is far older than just 10,000 years when the science was still very much in its youth. However in the meantime they have come up with a theory that is just as believable as the six day creation story.

I still find it completely unbelievable that we live on an unremarkable rock in a seemingly infinite universe. I find it completely unbelievable that I am made of individual 'bags' of water controlled by a long molecule in the shape of a double helix. I find it completely unbelievable that objects are pulled together through the vacuum of space by an invisible force that has a magnitute proportional to the mass of the two objects multiplied together.

How believable something is, is not a very objective way to gather information about the universe. To decide if a theory or hypothesis is accurate, we don't go on our gut instinct - otherwise the overwhelming majority of what is currently accepted would have been scrapped immediately after first being proposed. What we do instead, is we take the hypothesis and put it to the test, by using it to make predictions and seeing if they hold true under various conditions. If we collect enough evidence that supports the theory, and none that goes against the theory, we conclude that the theory is suitably accurate to become accepted, untill we are able to refine/modify the theory to even better fit the available evidence.

And at the end of this exhaustive process, when all the vast quantities of evidence we have gathered over 50 years has unanimously agreed with the theory - you decide all of this is wrong because "it doesn't sound believable"? How unbelievably arrogant.

To a moderator: recommend this thread be moved to pseudo, on the basis that galexander presents unsupported and opinionated views and ignores any evidence posted to the contrary.

But drowsy turtle you clearly have misunderstood what I have said, or just blatantly ignored the point because you didn't have a good enough answer:

Originally Posted by drowsy turtle

Originally Posted by galexander

I found it peculiar that you appear to have completely misunderstood the following:

Originally Posted by galexander

The differences in densities between the rock concerned would be minute and would not produce the huge forces necessary to deform rock.

The difference in density is vast, hence the variation in velocities of seismic waves through the mantle.

I was not referring to seismic wave propagation but the ability of minute density differentials resulting from equally minute temperature differences to deform solid rock.

I believe it is you who misunderstands. The velocity of waves through a material is a function of the density; greater velocities (essentially) relate directly to greater densities.

In the first instance I was not referring to seismic waves, you raised the subject of seismic waves. I was referring to the differences in densities between rock of different temperatures and that these density differentials would be so minute as to be unable to deform rock.

Understand now?

You also failed to answer another important point I raised:

Originally Posted by drowsy turtle

Originally Posted by galexander

wrote:
The convective cells you are proposing travel horizontally underneath the Earth's crust in parallel lines over many thousands of miles.

Do they? Why do you say that?

It is only too apparent why I said that. The currents produced by convective cells must travel in parallel lines over huge swathes of the Earth's surface for a continent to move the way you propose. That is move in the same direction for thousands upon thousands of miles and without being broken up into smaller islands. These convective currents would also have move in parallel lines directly beneath the surface and horizontally for 1000's of miles. How is this possible?

Is it JUST ONE convective cell which had pushed the the various parts of Pangaea outwards?



And it is YOU who are admitting defeat drowsy turtle by making notes to moderators asking for this thread to be moved to Pseudoscience.

The truth is you are a very bad loser and simply don't want to admit that your science could be in any way wrong.

Originally Posted by galexander

And it is YOU who are admitting defeat drowsy turtle by making notes to moderators asking for this thread to be moved to Pseudoscience.

The truth is you are a very bad loser and simply don't want to admit that your science could be in any way wrong.

i think drowsy was merely expressing his frustration with your inability to come to terms with what appears to be very straightforward science
closing your eyes to the evidence (or failing to understand it) and then denying the existence of that very evidence does elicit images of ostriches and sand in my head

my normal reaction is to allow quite some latitude before deciding to move a topic to pseudoscience, but i'm willing to listen to the opinion of other members should a fair number of the regulars feel that's where this thread belongs

my normal reaction is to allow quite some latitude before deciding to move a topic to pseudoscience, but i'm willing to listen to the opinion of other members should a fair number of the regulars feel that's where this thread belongs

When I first saw the title of this thread "How is sand formed" I was like "what a snore fest" and then I thought about making a joke about pounding sand up an ass but I couldn't figure out a good way to throw it down but in the process of reading the thread I remembered that geology was my favorite science when I was a kid cause' it was like I couldn't go anywhere and not fill my pockets with rock's, sometimes so many it made it hard to walk, and I became interested in the thread but then it started to get all poly-quotey and making my eyeballs bug and my whole point is that galexander's view's of science are like those rocks I looked at but didn't pick up cause they had a shape and color to suggest that they might not be rock's and so I think this thread doe's belong in pseudoscience like those pseudorock's I never picked up and put in my pocket and I think it's a bummer I never did find a good opening for a "pound sand up an ass" joke but that's okay cause this is like the hugest run on sentence in the history of run on sentences for me at least anyways so everyone have a nice day and thank's and stuff ya'll.

what's a pseudo-rock ?

Originally Posted by GiantEvil

my normal reaction is to allow quite some latitude before deciding to move a topic to pseudoscience, but i'm willing to listen to the opinion of other members should a fair number of the regulars feel that's where this thread belongs

When I first saw the title of this thread "How is sand formed" I was like "what a snore fest" and then I thought about making a joke about pounding sand up an ass but I couldn't figure out a good way to throw it down but in the process of reading the thread I remembered that geology was my favorite science when I was a kid cause' it was like I couldn't go anywhere and not fill my pockets with rock's, sometimes so many it made it hard to walk, and I became interested in the thread but then it started to get all poly-quotey and making my eyeballs bug and my whole point is that galexander's view's of science are like those rocks I looked at but didn't pick up cause they had a shape and color to suggest that they might not be rock's and so I think this thread doe's belong in pseudoscience like those pseudorock's I never picked up and put in my pocket and I think it's a bummer I never did find a good opening for a "pound sand up an ass" joke but that's okay cause this is like the hugest run on sentence in the history of run on sentences for me at least anyways so everyone have a nice day and thank's and stuff ya'll.

Congrats on a fantastically long sentence.

what's a pseudo-rock ?

Anything that look's like a rock but isn't. Generally dried old critter poo.

Congrats on a fantastically long sentence.

Thank's KALSTER.

Originally Posted by galexander

It is only too apparent why I said that. The currents produced by convective cells must travel in parallel lines over huge swathes of the Earth's surface for a continent to move the way you propose. That is move in the same direction for thousands upon thousands of miles and without being broken up into smaller islands. These convective currents would also have move in parallel lines directly beneath the surface and horizontally for 1000's of miles. How is this possible?

I have already said, a number of times, that convection is not generally considered a major mechanism for the movement of plates.

Originally Posted by galexander

And it is YOU who are admitting defeat drowsy turtle by making notes to moderators asking for this thread to be moved to Pseudoscience.

The truth is you are a very bad loser and simply don't want to admit that your science could be in any way wrong.

You may have noticed that I spend a significant amount of time posting in the pseudoscience sub-forum. If this thread moves there, it won't necessarily mean I stop replying.

I recommended the thread move there simply because your ramblings are not scientific, and nor is your approach to evidence and/or critique. I wouldn't like for your unproven and often completely wrong ideas to be mistaken as mainstream science by any silent observers.

Originally Posted by GiantEvil

my normal reaction is to allow quite some latitude before deciding to move a topic to pseudoscience, but i'm willing to listen to the opinion of other members should a fair number of the regulars feel that's where this thread belongs

When I first saw the title of this thread "How is sand formed" I was like "what a snore fest" and then I thought about making a joke about pounding sand up an ass but I couldn't figure out a good way to throw it down but in the process of reading the thread I remembered that geology was my favorite science when I was a kid cause' it was like I couldn't go anywhere and not fill my pockets with rock's, sometimes so many it made it hard to walk, and I became interested in the thread but then it started to get all poly-quotey and making my eyeballs bug and my whole point is that galexander's view's of science are like those rocks I looked at but didn't pick up cause they had a shape and color to suggest that they might not be rock's and so I think this thread doe's belong in pseudoscience like those pseudorock's I never picked up and put in my pocket and I think it's a bummer I never did find a good opening for a "pound sand up an ass" joke but that's okay cause this is like the hugest run on sentence in the history of run on sentences for me at least anyways so everyone have a nice day and thank's and stuff ya'll.

I'd take it easy GiantEvil.

Don't get so worked up about things!

Originally Posted by drowsy turtle

I have already said, a number of times, that convection is not generally considered a major mechanism for the movement of plates.[

Okay then drowsy turtle, what IS or ARE the other mechanisms for the movement of plates?

I get the strong impression that geologists aren't really sure about it themselves and they keep changing what they are saying.

One minute they are telling you in books and on the internet that the asthenosphere is fluid and has convective currents and then the next minute it is completely solid.

What? Did it just suddenly solidify while we were talking..............................

Originally Posted by galexander

I get the strong impression that geologists aren't really sure about it themselves and they keep changing what they are saying.

One minute they are telling you in books and on the internet that the asthenosphere is fluid and has convective currents and then the next minute it is completely solid.

What? Did it just suddenly solidify while we were talking..............................

black&white thinking - why should something have to be totally solid or totally fluid ?
after all we KNOW that certain materials behave either way depending on the circumstances

as for "scientists who keep changing their minds", that's something that's more seen as a flaw in politics or religion - you seem to think that a scientific theory that is no longer the same as a centuries old original displays signs of weakness rather than robust vitality
no wonder you seem to try and evaluate present-day scientific theories by how they originated in the 17th, 18th or 19th century : you don't seem to realise that a strong scientific theory worth its salt has to incorporate new findings in its structure or become outdated or even irrelevant - it's no use pointing out the flaws in Newton's or Darwin's original description of the theory that carries their name if you don't want to take into account the fact that the present incarnation may well have addressed the flaws of the original

I concur with sentiments to move to pseudo.

The sand formation idea was given fair treatment by at least two geologists on the forum.

Clearly the OP's chief agenda isn't science and scientific discovery, rather an irrational criticism of science.

My complaint is that scientists tend to live in ivory towers.*

And scientists do not appear to accept shades of opinion, everything has to be black or white.*

Much of the science we believe in (and I use the word 'believe' with some prudence) is antiquated somewhat. I would go so far as to say that the longer ago a scientific law was proposed, the more likely it is wrong.*

Because of this law physics is the worst off, followed by chemistry and then geology.

Peer reviewed journals and scientific symposia (for scientists in ivory towers) are one thing Ophiolite but I like to use a little common sense.

While there are doubtless many academics in science who find themselves in "ivory towers," the strawman argument that the OP has created is a gross mischaracterization. One might more easily argue that there exist ignorant lay-persons in dung filled basements than geologists in ivory towers. Furthermore, even if there were a willful disconnect among geologists or any scientist from the rest of society (which is what the "ivory towers" trope refers to), it doesn't automatically follow that they are wrong in their conclusions.

As for "common sense," this everyday-man brand of self-identification is not only ignorant but irrational -any person who lays claim to common sense over the opportunity for true education based on the years of experience and observation by those who came before is doomed to failure. Where true "common sense" exists, rational science and empirical discovery follow. In short, if the OP truly had "common sense," he'd demonstrate it with a bit less pseudoscientific advancement.

Ophiolite answered the bulk of galexander's strange beliefs. galexander is clearly not interested in education or scientific discovery.

The OP's anti-science agenda is not worth keeping in the real science sub-forums.

Originally Posted by SkinWalker

I concur with sentiments to move to pseudo.

The sand formation idea was given fair treatment by at least two geologists on the forum.

Clearly the OP's chief agenda isn't science and scientific discovery, rather an irrational criticism of science.

My complaint is that scientists tend to live in ivory towers.*

And scientists do not appear to accept shades of opinion, everything has to be black or white.*

Much of the science we believe in (and I use the word 'believe' with some prudence) is antiquated somewhat. I would go so far as to say that the longer ago a scientific law was proposed, the more likely it is wrong.*

Because of this law physics is the worst off, followed by chemistry and then geology.

Peer reviewed journals and scientific symposia (for scientists in ivory towers) are one thing Ophiolite but I like to use a little common sense.

While there are doubtless many academics in science who find themselves in "ivory towers," the strawman argument that the OP has created is a gross mischaracterization. One might more easily argue that there exist ignorant lay-persons in dung filled basements than geologists in ivory towers. Furthermore, even if there were a willful disconnect among geologists or any scientist from the rest of society (which is what the "ivory towers" trope refers to), it doesn't automatically follow that they are wrong in their conclusions.

As for "common sense," this everyday-man brand of self-identification is not only ignorant but irrational -any person who lays claim to common sense over the opportunity for true education based on the years of experience and observation by those who came before is doomed to failure. Where true "common sense" exists, rational science and empirical discovery follow. In short, if the OP truly had "common sense," he'd demonstrate it with a bit less pseudoscientific advancement.

Ophiolite answered the bulk of galexander's strange beliefs. galexander is clearly not interested in education or scientific discovery.

The OP's anti-science agenda is not worth keeping in the real science sub-forums.

Well it is obvious to me SkinWalker that you are very much taking a reactionary standpoint.

And I certainly don't believe Ophiolite answered the 'bulk' of my questions. At best Ophiolite was obscure and hair-splitting, at worst he was just clouding the issue.

I motion that the Theory of Continental Drift itself should be moved to the Pseudoscience section where it should remain as an object of curiosity.

And further drowsy turtle failed to properly answer the points I addressed below which is curious if he is a qualified geologist as he seems to claim:

But drowsy turtle you clearly have misunderstood what I have said, or just blatantly ignored the point because you didn't have a good enough answer:

Originally Posted by drowsy turtle

Originally Posted by galexander

I found it peculiar that you appear to have completely misunderstood the following:

Originally Posted by galexander

The differences in densities between the rock concerned would be minute and would not produce the huge forces necessary to deform rock.

The difference in density is vast, hence the variation in velocities of seismic waves through the mantle.

I was not referring to seismic wave propagation but the ability of minute density differentials resulting from equally minute temperature differences to deform solid rock.

I believe it is you who misunderstands. The velocity of waves through a material is a function of the density; greater velocities (essentially) relate directly to greater densities.

In the first instance I was not referring to seismic waves, you raised the subject of seismic waves. I was referring to the differences in densities between rock of different temperatures and that these density differentials would be so minute as to be unable to deform rock.

Understand now?

You also failed to answer another important point I raised:

Originally Posted by drowsy turtle

Originally Posted by galexander

wrote:
The convective cells you are proposing travel horizontally underneath the Earth's crust in parallel lines over many thousands of miles.

Do they? Why do you say that?

It is only too apparent why I said that. The currents produced by convective cells must travel in parallel lines over huge swathes of the Earth's surface for a continent to move the way you propose. That is move in the same direction for thousands upon thousands of miles and without being broken up into smaller islands. These convective currents would also have move in parallel lines directly beneath the surface and horizontally for 1000's of miles. How is this possible?

Is it JUST ONE convective cell which had pushed the the various parts of Pangaea outwards?

Originally Posted by galexander

Originally Posted by drowsy turtle

I have already said, a number of times, that convection is not generally considered a major mechanism for the movement of plates.[

Okay then drowsy turtle, what IS or ARE the other mechanisms for the movement of plates?

I'm fairly sure I've written about this 3 or 4 times already... Do you read my replies at all any more? Or just pick out individual sentances where you think you can reply to make yourself look clever? Either way...

You can read about the many theories, and a little about the evidence supporting them, on this wiki page.

Originally Posted by SkinWalker

I concur with sentiments to move to pseudo.

ok - it looks that the majority of moderators / members who replied are in favour of moving this thread to pseudo-science, so that's where it goes

in my case it's goodbye as i rarely if ever visit that part of the forum

Originally Posted by galexander

And further drowsy turtle failed to properly answer the points I addressed below which is curious if he is a qualified geologist as he seems to claim

Firstly, I never claimed to be a qualified geologist. In fact, I told you in another thread that I am a student.

Secondly, in the section you quote, I answered your initial query in my first reply; you said the differences in density within the mantle were tiny - I explained that we can use seismic wave velocities to demonstrate that the density of the material in the mantle differs very greatly with depth.

You subsequent ramblings had nothing to do with this, so I ignored them. They were also along the same theme as many of your other posts (which I replied to at various times); that because categorically proving the existance of mantle convection cells is problematic, continental drift cannot occur.

In fact you have it backwards; mantle convection, as a mechanism for plate movement, was proposed long after it was first accepted that the lithosphere was made of seperate, moving plates.

Since then, mantle convection has lost favour in the scientific community, and isn't usually considered a major mechanism in plate movement (see previous post).


Does that answer your question (whatever your question actually was)?