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Thread: How is Sand Formed?

  1. #101  
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    Quote Originally Posted by drowsy turtle
    Quote Originally Posted by galexander
    how do you explain the following:

    I was giving my tropical aquarium a spring clean one day and having emptied out most of the gravel from the bottom of the tank I noticed some sand particles.

    I couldn't believe what I was looking at as you don't want sand anywhere near glass surfaces. So how did the sand get there?
    Probably present in the gravel from the start. Or they may have been pieces of mineralised fish poo, or various other detritus.

    Quote Originally Posted by galexander
    You claim yourself that the sand particles 'fall' out of the gravel by abrasion.
    "Falling" is a bit of a weak way of putting it. It's like saying fragments of pottery fall out of a jug when it hits the floor.

    Quote Originally Posted by galexander
    But I simply can't believe this.
    As I've explained, what you can or cannot believe is not an objective measure of the worth of a hypothesis.

    Quote Originally Posted by galexander
    Also in my tropical aquarium are a unique variety of marine rocks which are full of holes. (The fish really enjoy swimming through the holes and exploring them!) I don't know what the rocks are called or where exactly they come from but I have seen them on a TV documentary on marine matters in situ, i.e. at the bottom of the sea.
    You're most likely talking about vesicular lavas, since they're very common in aquariums. This being the case, the holes form during the de-gassing of a magma, not through sedimentary processes.

    The documentary you saw was most likely about carbonates. Carbonates do dissolve and re-precipitate; quite often fossils you find in limestones have been dissolved and completely replaced with new carbonates.

    Quote Originally Posted by galexander
    Perhaps the rocks are gradually dissolving in the water and the mineral in question, silica, has then precipitated out of solution forming sand particles.
    Silica precipitating out of water forms crystals - and does so very slowly. It will also tend to precipitate around existing material or on surfaces, not as free-floating particles. Imagine limescale in a kettle - the limkescale forms around the edge of the kettle, not as seperate grains. This, too, I've explained to you before, but again you have apparantly ignored me.

    Further reading

    drowsy turtle said the following concerning the presence of sand particles in my aquarium gravel:

    Quote Originally Posted by drowsy turtle
    Probably present in the gravel from the start. Or they may have been pieces of mineralised fish poo, or various other detritus.
    I had used specialist aquarium gravel which is dry and clean of contaminating particles like sand. As for the mineralised detritus; no, I was quite certain it was sand.

    Unless of course that is how you are suggesting that sand is formed; that it is mineralised detritus?

    You do have the habit of throwing suggestions about.

    Quote Originally Posted by drowsy turtle
    You're most likely talking about vesicular lavas, since they're very common in aquariums. This being the case, the holes form during the de-gassing of a magma, not through sedimentary processes.

    The documentary you saw was most likely about carbonates. Carbonates do dissolve and re-precipitate; quite often fossils you find in limestones have been dissolved and completely replaced with new carbonates.
    Again you are throwing suggestions around.

    I am quite certain the rock is not volcanic as it is not dark and basaltic, it is a light colour.

    The rock does not look like limestone to me as it has a 'grainy' texture to it. Further limestone may not be a suitable stone for an aquarium due to it solubility.
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  2. #102  
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    Quote Originally Posted by galexander
    Quote Originally Posted by drowsy turtle
    Probably present in the gravel from the start. Or they may have been pieces of mineralised fish poo, or various other detritus.
    I had used specialist aquarium gravel which is dry and clean of contaminating particles like sand. As for the mineralised detritus; no, I was quite certain it was sand.

    Unless of course that is how you are suggesting that sand is formed; that it is mineralised detritus?

    You do have the habit of throwing suggestions about.
    Given a vague situation, I can only suggest vague explanations.

    What was the mineral composition of the gravel and the sand, for instance?

    Quote Originally Posted by galexander
    Again you are throwing suggestions around.

    I am quite certain the rock is not volcanic as it is not dark and basaltic, it is a light colour.
    I kept tropical fish for many years. I am aware that lavas are commonly used in aquariums, and had a reasonably pale lava rock in my own aquarium.

    Simply because the rock does not resemble one type of extrusive rock you are familiar with does nto mean it is not volcanic. For instance, granites do not resemble basalts in colour, or even very much in mineral composition.

    Pumice, for instance, is volcanic but alse pale in colour:



    Quote Originally Posted by galexander
    The rock does not look like limestone to me as it has a 'grainy' texture to it. Further limestone may not be a suitable stone for an aquarium due to it solubility.
    Precisely. Hence I suggest that the rock you have is in fact a lava.
    "The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair." ~ Douglas Adams
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    Most aquarium stones are either limestone or sandstone. Either can produce a bit of sand over time as the stone continues to weather in the aquarium.

    The sand is most definitely not precipitating from the aquarium solution if standard water mixes for either fresh or salt water environments are being used. The solution needed to start a reaction that would precipitate a mineral would be one that had to be deliberately intended to do so and would not be a solution fish would thrive in if they survived at all.

    For instance, to precipitate silica from a solution, an alkaline silicate solution would need to be reacted with a mineral acid like sulfuric. The two solutions would probably have to be added together while the aquarium water was being agitated enough injure the fish. If that didn't kill them, the alkaline conditions would be enough to do the job.

    In short, either you're mistaken about the source of your "sand" or you're making it all up. Or you just really hate your fish.
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  4. #104  
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    Quote Originally Posted by drowsy turtle
    Quote Originally Posted by galexander
    Quote Originally Posted by drowsy turtle
    Probably present in the gravel from the start. Or they may have been pieces of mineralised fish poo, or various other detritus.
    I had used specialist aquarium gravel which is dry and clean of contaminating particles like sand. As for the mineralised detritus; no, I was quite certain it was sand.

    Unless of course that is how you are suggesting that sand is formed; that it is mineralised detritus?

    You do have the habit of throwing suggestions about.
    Given a vague situation, I can only suggest vague explanations.

    What was the mineral composition of the gravel and the sand, for instance?

    Quote Originally Posted by galexander
    Again you are throwing suggestions around.

    I am quite certain the rock is not volcanic as it is not dark and basaltic, it is a light colour.
    I kept tropical fish for many years. I am aware that lavas are commonly used in aquariums, and had a reasonably pale lava rock in my own aquarium.

    Simply because the rock does not resemble one type of extrusive rock you are familiar with does nto mean it is not volcanic. For instance, granites do not resemble basalts in colour, or even very much in mineral composition.

    Pumice, for instance, is volcanic but alse pale in colour:



    Quote Originally Posted by galexander
    The rock does not look like limestone to me as it has a 'grainy' texture to it. Further limestone may not be a suitable stone for an aquarium due to it solubility.
    Precisely. Hence I suggest that the rock you have is in fact a lava.
    This looks like the stone in question:



    http://www.zooplus.co.uk/shop/fish/d...cks/43351#more

    The website gives the following information:

    The Jura coral like rock is a unique rock with light beige coloring and many cavities.

    This stone comes from the petrified sea deposits that were cause by tectonic shifts between mountains. They are gathered individually and carefully cleaned. The bizarre form and many cavities are caused from natural erosion over thousands of years.
    And a point of detail. The sand appeared in my aquarium before I had introduced these rocks. In my aquarium previously had been gravel, quartz pebbles and flint pebbles and bog wood.
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    a bit sad really - within days of being transferred to pseudoscience this thread appears to have died
    starved from being deprived of the oxygen of exposure ?
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  6. #106  
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    However well washed the gravel was before being shipped from the packaging facility to your local retail outlet the very act of transporting it is probably the source of the sand.
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    Quote Originally Posted by marnixR
    a bit sad really - within days of being transferred to pseudoscience this thread appears to have died
    starved from being deprived of the oxygen of exposure ?
    If you are the objective Moderator you say you are why go to such an effort to rub it in that my thread was moved the Pseudoscience?

    Gives you a feeling of power does it?
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    no it doesn't - if you had any feel of what the mods on this forum are like you'll notice that power-craziness isn't one of their characteristics

    i would have kept your thread in Earth Sciences if it hadn't been for the opinion of other members of this forum, whose opinion i value

    if moving this thread to another part of the forum means it died prematurely i'm awfully sorry - that's the reason why i posted the post you quoted, not for any gratification i might get out schadenfreude

    [edit]
    TheBiologista, if you can see it in your heart to move this thread back to Earth Sciences, would you be so kind to do so ? however, the decision is totally yours, no compulsion is implied
    [/edit]
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  9. #109  
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    Quote Originally Posted by marnixR
    TheBiologista, if you can see it in your heart to move this thread back to Earth Sciences, would you be so kind to do so ? however, the decision is totally yours, no compulsion is implied
    Do you no longer consider this thread to be pseudoscience? Has the majority opinion on the ES forum changed? If you would like me to move the thread back there, I can certainly do that.
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    not so much that i don't consider this thread pseudoscience, it's just that within Earth Sciences i've got into the habit of lowering the bar of what is acceptable subject matter

    + the last thing i want to be accused is to move a thread to pseudoscience as a putdown rather than because of a better fit with the strict definition of pseudoscience

    however, since the thread is in your domain, the decision is totally yours, i want the decision made purely on your opinion, not mine
    (sorry if this sounds like a cop-out, that's probably because it is)
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  11. #111  
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    Quote Originally Posted by marnixR
    not so much that i don't consider this thread pseudoscience, it's just that within Earth Sciences i've got into the habit of lowering the bar of what is acceptable subject matter

    + the last thing i want to be accused is to move a thread to pseudoscience as a putdown rather than because of a better fit with the strict definition of pseudoscience

    however, since the thread is in your domain, the decision is totally yours, i want the decision made purely on your opinion, not mine
    (sorry if this sounds like a cop-out, that's probably because it is)
    If you change your mind, feel free to bounce it back my way.
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  12. #112  
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    cheers
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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    Quote Originally Posted by GiantEvil
    However well washed the gravel was before being shipped from the packaging facility to your local retail outlet the very act of transporting it is probably the source of the sand.
    I don't believe so.

    I think the most the transport of a bag of gravel will produce is a fine powder in the bottom of the bag.
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    I think the most the transport of a bag of gravel will produce is a fine powder in the bottom of the bag.
    It's still smaller particles produced mechanically. The common mechanism of sand production.
    I was some of the mud that got to sit up and look around.
    Lucky me. Lucky mud.
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    Quote Originally Posted by GiantEvil
    I think the most the transport of a bag of gravel will produce is a fine powder in the bottom of the bag.
    It's still smaller particles produced mechanically. The common mechanism of sand production.
    If sand particles were able to come from gravel then you would expect to see the 'holes' the particles came from.

    Do you see holes in gravel where the sand came from?
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    The sand particles would be knocked off the edges and vertices of the gravel, not scooped from the planer surfaces.
    I was some of the mud that got to sit up and look around.
    Lucky me. Lucky mud.
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    Quote Originally Posted by GiantEvil
    The sand particles would be knocked off the edges and vertices of the gravel, not scooped from the planer surfaces.
    They'd still leave holes though.

    You can't get round that.
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    Not if the grain was already jutting out and not if the cementing mineral dissolved around it, smoothing in the process.

    The only other explanations, if not from erosion of your aquarium rocks is precipation, erosion from something else, or introduction to the aquarium by some other means.

    The one thing we're sure of is that it isn't due to the mineral precipating from the aquarium's solution. Such a chemical process would not have an environment habitable to normal aquarium fish.

    Is your aquarium fresh or salt water?
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    Quote Originally Posted by SkinWalker
    Not if the grain was already jutting out and not if the cementing mineral dissolved around it, smoothing in the process.

    The only other explanations, if not from erosion of your aquarium rocks is precipation, erosion from something else, or introduction to the aquarium by some other means.

    The one thing we're sure of is that it isn't due to the mineral precipating from the aquarium's solution. Such a chemical process would not have an environment habitable to normal aquarium fish.

    Is your aquarium fresh or salt water?
    My aquarium is fresh water.

    But I was in the habit of adding a liquid wood extract to the water which produces an environment fish from the Amazon prefer. This presumably would have contained tannic acid.
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    In my last two posts to you I issued three challenges. You have avoided directly addressing these challenges. Please do so. You appear to concede you are mistaken, yet avoid saying so, or attempting to refute my well founded statements. This does nothing to move our discussion forward. So, I repeat, please address each of those challenges.

    Quote Originally Posted by galexander
    Okay Ophiolite but how do you explain the following:

    I was giving my tropical aquarium a spring clean one day and having emptied out most of the gravel from the bottom of the tank I noticed some sand particles.
    If you appreciate the nature of scientific research you will appreciate that the scenario you have presented is of almost zero scientific value. It is a wholly uncontrolled situation. Other posters have provided possible explanations for your observations, which seem to me plausible. However, I would not even attempt to answer this based on the sketchy data you have provided. Nor, would any answer have any real relevance to your underlying assertions which are refuted by well documented research by thousands of geologists and geomorphologists.

    Quote Originally Posted by galexander
    You claim yourself that the sand particles 'fall' out of the gravel by abrasion. But I simply can't believe this.
    For perhaps the third time your inability to believe something has zero relevance in a scientific discussion.

    Secondly, I do not claim sand particles fall out of gravel by abrasion alone. I have stated that sand particles 'emerge' ('fall' out if you prefer) from rock through the process of weathering. The weathering process loosens the cohesion between grains and changes the chemistry of some grains, producing 'softer' minerals.

    Quote Originally Posted by galexander
    The dry, academic textbooks appear to say something else however...........
    If you approach textbooks with an enquiring mind, think deeply about the implications of what is written and marry this up with reasoned field observations, then they are most certainly not dry, but alive, vibrant and inspiring.
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    Sand is created from the weathering and erosion of rock and rock particles to a size that is between .06-2.0 mm in diameter. Sand deposits can be of quartz particles, gypsum particles, fractured obsidian, oolites, glauconite, shell or coral fragments, or other mineral or rock material.


    Sand creation processes include the following steps:

    1.) Larger rock is broken down into progressively smaller and smaller particles by mostly mechanical weathering which include abrasion during transportation, freeze/thaw cycles, and fracture from gravity induced impacts.

    2.) The mechanically weathered rocks are now further weathered and reduced in size by the effects of chemical weathering, either through the chemical interactions with naturally acidic rainfall and water or from chemicals released by organisms.

    3.) At a certain size, the rock particles are easily transported and tossed about by wind and water. The abrasion of particle against particle further reduces their size. Eventually in the erosion process, the particles are carried by wind and can form dunes, or are carried by water to river banks, lakes, or seas where they can form beaches.
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    Quote Originally Posted by Siberian Fox
    Sand is created from the weathering and erosion of rock and rock particles to a size that is between .06-2.0 mm in diameter. Sand deposits can be of quartz particles, gypsum particles, fractured obsidian, oolites, glauconite, shell or coral fragments, or other mineral or rock material.


    Sand creation processes include the following steps:

    1.) Larger rock is broken down into progressively smaller and smaller particles by mostly mechanical weathering which include abrasion during transportation, freeze/thaw cycles, and fracture from gravity induced impacts.

    2.) The mechanically weathered rocks are now further weathered and reduced in size by the effects of chemical weathering, either through the chemical interactions with naturally acidic rainfall and water or from chemicals released by organisms.

    3.) At a certain size, the rock particles are easily transported and tossed about by wind and water. The abrasion of particle against particle further reduces their size. Eventually in the erosion process, the particles are carried by wind and can form dunes, or are carried by water to river banks, lakes, or seas where they can form beaches.
    I will repeat my original question which you ALL so far have failed to answer.

    Why do you not see piles of sand at the bases of rocky inland cliffs?

    And do rocks really get broken up into smaller and smaller particles until they eventually become particles of sand? Is this realistic? I believe a rock can survive out in the open for thousands and thousands of years without being "broken up".
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    2 possible explanations spring to mind : some of the sand might get blown or washed away + the rest could become incorporated into the soil

    i'm sure that's not an exhaustive set of explanations, there's likely to be other mechanisms involved
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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    Quote Originally Posted by galexander
    Why do you not see piles of sand at the bases of rocky inland cliffs?
    You can see such piles.

    There is a picture in my geology textbook of that very thing, accumulated quartz and other mineral grains at the base of a granite cliff or basolith. The accumulated sand is very clear in the picture.

    The caption under the picture reads, "Exposure of weathered granite. As the parent rock disintegrates, quartz grains and partially decomposed feldspar accumulate."*

    *Levin, H. The earth through time, 8th ed., page 67, Figure 4-32. John Wiley & Sons, Inc.

    Quote Originally Posted by galexander
    I believe a rock can survive out in the open for thousands and thousands of years without being "broken up".
    Some rocks do survive for thousands of years without being broken up, depending on local conditions, but most weather eventually. The process can take much longer than thousands of years, though - think geologic time - millions or tens of millions of years.
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    Quote Originally Posted by galexander
    I will repeat my original question which you ALL so far have failed to answer.

    Why do you not see piles of sand at the bases of rocky inland cliffs?
    You do. Particularly where rainfall and wind aren't sufficient to remove these piles.

    Now that the question is answered, we can close the thread, yes?
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    Quote Originally Posted by SkinWalker
    Quote Originally Posted by galexander
    I will repeat my original question which you ALL so far have failed to answer.

    Why do you not see piles of sand at the bases of rocky inland cliffs?
    You do. Particularly where rainfall and wind aren't sufficient to remove these piles.

    Now that the question is answered, we can close the thread, yes?
    No.

    I still have an objection.

    The implication is that in a sandy desert ALL the rock eventually turns into sand.

    I dispute this.

    I do not believe that rock can disintegrate in this manner.

    And it still does not explain where the sandy beaches come from in areas of sedimentary rock.

    You have said that sand is the crystal grains of rock. But there ARE NO crystal grains in sedimentary rock.

    Not so fast you lot. This thread IS NOT closed, it is still very much open.
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  27. #127  
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    Quote Originally Posted by galexander
    The implication is that in a sandy desert ALL the rock eventually turns into sand.

    I dispute this.

    I do not believe that rock can disintegrate in this manner.
    not sure if i follow you - obviously only the silica portion of a rock can turn to sand + provided the grain size is of the correct size to be classified as sand

    why does it stretch your belief that rocks could disintegrate in this fashion - given enough time, what's preventing them from disintegrating ?
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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    Quote Originally Posted by marnixR
    Quote Originally Posted by galexander
    The implication is that in a sandy desert ALL the rock eventually turns into sand.

    I dispute this.

    I do not believe that rock can disintegrate in this manner.
    not sure if i follow you - obviously only the silica portion of a rock can turn to sand + provided the grain size is of the correct size to be classified as sand

    why does it stretch your belief that rocks could disintegrate in this fashion - given enough time, what's preventing them from disintegrating ?
    Is it your honest opinion that if you had a long enough time available and you were able to sit watching a large boulder eroding in a desert, that you would witness the boulder slowly turning into sand?

    In my opinion when boulders fragment as a result of weathering there is no statistical bias in favour of the size of the fragments being of the same size as sand particles.

    If you break up rocks with a large hammer you do NOT end up with piles of sand. In fact I would be highly surprised if you found any sand whatsoever having broken up rocks using a hammer.
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    i doubt whether you can compare the action of a hammer with that of erosion
    different time scale + different means of disaggregation
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    Quote Originally Posted by galexander
    If you break up rocks with a large hammer you do NOT end up with piles of sand. In fact I would be highly surprised if you found any sand whatsoever having broken up rocks using a hammer.
    Use your imagination! If by "sand" you mean sand-sized particles or mineral grains, such as quartz, which would normally be found in sand, then certainly you do, if you do it the same way that nature does it:

    1) break rock into several smaller pieces

    2) break those smaller pieces into still smaller pieces

    3) break the still smaller pieces into even smaller pieces,

    etc, until you end up with sand-sized particles.

    In nature the "hammer" is such things as frost wedging, collisions between falling rocks (gravity), reduction in size from being knocked against other rocks by the wind or tumbled along by water, etc.

    This is a simplification, of course. Not all rocks are broken down entirely by mechanical processes. There is also chemical weathering.
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    Quote Originally Posted by jsloan
    Quote Originally Posted by galexander
    If you break up rocks with a large hammer you do NOT end up with piles of sand. In fact I would be highly surprised if you found any sand whatsoever having broken up rocks using a hammer.
    Use your imagination! If by "sand" you mean sand-sized particles or mineral grains, such as quartz, which would normally be found in sand, then certainly you do, if you do it the same way that nature does it:

    1) break rock into several smaller pieces

    2) break those smaller pieces into still smaller pieces

    3) break the still smaller pieces into even smaller pieces,

    etc, until you end up with sand-sized particles.

    In nature the "hammer" is such things as frost wedging, collisions between falling rocks (gravity), reduction in size from being knocked against other rocks by the wind or tumbled along by water, etc.

    This is a simplification, of course. Not all rocks are broken down entirely by mechanical processes. There is also chemical weathering.
    But is it not a fantastic coincidence that all the particles on a sandy beach are of the same size?

    Beside when a rock gets "fractured" by weathering (and how often does that happen?) the fracture will go clean through the crystal grains. If you look at the fracture through a magnifying glass you WILL NOT see sand particles protruding from the fracture just waiting to fall out.

    Listen to some common sense for a change, please.
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  32. #132  
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    Quote Originally Posted by galexander

    But is it not a fantastic coincidence that all the particles on a sandy beach are of the same size?
    No it isnt. as was pointed out earlier in the thread the particles at a beach are naturally sorted by the wave actions. To find grains of a different size range from sand all you haveto do is move inland and you will be likely to encounter smaller silts and clays along with much soils. Move further out from the shoreline and you will encounter increasingly large gravels, cobbles, etc.

    Quote Originally Posted by galexander
    Beside when a rock gets "fractured" by weathering (and how often does that happen?) the fracture will go clean through the crystal grains.
    Its happening right now. In fact it never stops happening, you are arguing from incredulity here.

    Quote Originally Posted by galexander
    If you look at the fracture through a magnifying glass you WILL NOT see sand particles protruding from the fracture just waiting to fall out.

    Listen to some common sense for a change, please.
    And who here has said that one fracture will result in a sand sized particle of rock? Its a process of rounding that happens slowly in most cases, on a one fracture and poof it all turned to sand process.

    Imagine a Cube, now cut off the corners of the cube, now cut off the corners left by the first cuts, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat,....

    This is how it works in a very simplified manner.
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  33. #133  
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    Quote Originally Posted by Paleoichneum
    Quote Originally Posted by galexander

    But is it not a fantastic coincidence that all the particles on a sandy beach are of the same size?
    No it isnt. as was pointed out earlier in the thread the particles at a beach are naturally sorted by the wave actions. To find grains of a different size range from sand all you haveto do is move inland and you will be likely to encounter smaller silts and clays along with much soils. Move further out from the shoreline and you will encounter increasingly large gravels, cobbles, etc.

    Quote Originally Posted by galexander
    Beside when a rock gets "fractured" by weathering (and how often does that happen?) the fracture will go clean through the crystal grains.
    Its happening right now. In fact it never stops happening, you are arguing from incredulity here.

    Quote Originally Posted by galexander
    If you look at the fracture through a magnifying glass you WILL NOT see sand particles protruding from the fracture just waiting to fall out.

    Listen to some common sense for a change, please.
    And who here has said that one fracture will result in a sand sized particle of rock? Its a process of rounding that happens slowly in most cases, on a one fracture and poof it all turned to sand process.

    Imagine a Cube, now cut off the corners of the cube, now cut off the corners left by the first cuts, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat,....

    This is how it works in a very simplified manner.

    Quote Originally Posted by Paleoichneum
    No it isnt. as was pointed out earlier in the thread the particles at a beach are naturally sorted by the wave actions. To find grains of a different size range from sand all you haveto do is move inland and you will be likely to encounter smaller silts and clays along with much soils. Move further out from the shoreline and you will encounter increasingly large gravels, cobbles, etc.
    It could easily be the other way around. The further out you go into the sea the muddier it gets and the closer to the cliff you are the larger the pebbles and boulders.

    But the point I was making is that on a sandy beach the grain size of the sand is always the same. You do not get finer sand and then courser sand higher up the beach, having been sorted out and separated by wave action. Nor do you get different coloured sands leading to a stripy beach!

    Quote Originally Posted by Paleoichneum
    Imagine a Cube, now cut off the corners of the cube, now cut off the corners left by the first cuts, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat, repeat,....
    This is an old, old one surely.....and it still sounds wrong. A pebble is eroded by wave action and then gets progressively smaller and smaller until.......yes you've guessed it, it turns into a particle of sand!

    So all particles of sand used to be a pebble at one time until erosion made them that much smaller!
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  34. #134 Parrot Fish 
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    Parrot fish eat coral and poop out sand beaches. Think about that next time you bury yourself in the sand!
    Intelligence is a gift, education an accomplishment.
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  35. #135  
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    I just read this ridiculous statement from you galexander.
    Quote Originally Posted by galexander
    But the point I was making is that on a sandy beach the grain size of the sand is always the same. You do not get finer sand and then courser sand higher up the beach, having been sorted out and separated by wave action. Nor do you get different coloured sands leading to a stripy beach!
    Rubbish. You clearly have never done any proper observation of beaches, nor have you read any research by individuals who have carried out such observation.

    You have persistently and consistently demonstrated a singular absence of knowledge, logic, scepticism, common sense, intelligence and any other known intellectual characteristic. Your ideas are wrong, your speculations silly, your arguments defective and your contribution to science is negative. I suppose your one saving grace is that you are not in government.
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  36. #136  
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    I thought It quite exciting .
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  37. #137  
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    Look under water.
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  38. #138  
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    Quote Originally Posted by Ophiolite
    You have persistently and consistently demonstrated a singular absence of knowledge, logic, scepticism, common sense, intelligence and any other known intellectual characteristic. Your ideas are wrong, your speculations silly, your arguments defective and your contribution to science is negative. I suppose your one saving grace is that you are not in government.
    I had forgotten about this classic bit of work by galexander. It really is amazing how obviously he has his head buried in the sand, so to speak.

    BTW I though he was posting on his breaks from the house of commons.
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  39. #139  
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    Quote Originally Posted by Geo
    I thought It quite exciting .
    Have you been playing too much rugby recently?
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  40. #140  
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    Quote Originally Posted by Ophiolite
    I suppose your one saving grace is that you are not in government.
    I'd probably still vote for him. At least he has some ideas, unlike most politicians - even if they are wrong.
    "The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair." ~ Douglas Adams
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  41. #141  
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    Quote Originally Posted by galaxender
    If you break up rocks with a large hammer you do NOT end up with piles of sand.
    Yes, eventually, you do. That's more or less how the manufacturers of abrasives like sandpaper and lapping compounds make their products, for example.

    If you imitate natural processes of erosion and deposition - if you collect and tumble and sort the product by size as you go (rocks break unevenly when struck at random, most often into a big piece or two easily observed and a bunch of little ones that end up scattered around - there's a branch of probability theory that deals with this), the sand will accumulate in visible quantities quite early in the process - piles of grains more or less sorted by size, shape, or mass, depending on your sorting procedure.

    To save yourself trouble, you can sweep up at a local rock shop, quarry, etc., and hose the pile down a slope.

    You will see what everyone sees at the bases of a cliffs everywhere, or in the deposition zones of streams washing from rocky ground, or in the wave zone of an ocean shoreline, and so forth.

    Where are you getting these silly notions about the world outside your room, and why do you keep repeating them? Get up, go outside, and look around.
    I just read this ridiculous statement from you galexander.
    galexander wrote:
    But the point I was making is that on a sandy beach the grain size of the sand is always the same. You do not get finer sand and then courser sand higher up the beach, having been sorted out and separated by wave action. Nor do you get different coloured sands leading to a stripy beach!
    This repeats an assertion made, and rebutted, on page one of this thread - and implied several times afterwards. This has become trolling.
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