Thread: Unusual Rock Formation

Was leafing through some personal photos and came across this one. We had a trailer near here once. This pic from 10 yrs ago. Little unusual rock formation called a Flowerpot and of course it's one of a few on Flowerpot Island in Lake Huron. Not sure how many there are as every now and then one might take a tumble. They actually have shored up some of these using brick & mortar. You can see on the big one here that asphalt has been placed on top to prevent erosion. You see some that have completely crumbled when you walk around island. They take you out by boat, drop you off and come back to get you later. The flowerpot is evidence of how high the water once was after ice age. Today with the land still rebounding 20000 yrs later, not hard to see the difference in water levels then and now. In fact it was even higher at one time and this is evident in caves carved out by water higher up the island.




https://www.pc.gc.ca/en/amnc-nmca/on...ctiv/flowerpot

Very good .They look like stone age Transformers.

Originally Posted by geordief

Very good .They look like stone age Transformers.

Somewhat. It was early June and the water was absolutely freezing. Theres a dock nearby and I thought I'd dangle my feet in the water while waiting for the zodiac and in less than a minute the heat loss made my lower leg and foot numb. Water is spectacularly clear there.

A little more in focus

Originally Posted by zinjanthropos

Was leafing through some personal photos and came across this one. We had a trailer near here once. This pic from 10 yrs ago. Little unusual rock formation called a Flowerpot and of course it's one of a few on Flowerpot Island in Lake Huron. Not sure how many there are as every now and then one might take a tumble. They actually have shored up some of these using brick & mortar. You can see on the big one here that asphalt has been placed on top to prevent erosion. You see some that have completely crumbled when you walk around island. They take you out by boat, drop you off and come back to get you later. The flowerpot is evidence of how high the water once was after ice age. Today with the land still rebounding 20000 yrs later, not hard to see the difference in water levels then and now. In fact it was even higher at one time and this is evident in caves carved out by water higher up the island.




https://www.pc.gc.ca/en/amnc-nmca/on...ctiv/flowerpot

Is this limestone? It has that blocky look.

According to this article yes. My memory is so bad as there are only two remaining standing

https://tobermory.com/do-see/sightse...owerpot-island

Originally Posted by zinjanthropos

According to this article yes. My memory is so bad as there are only two remaining standing

https://tobermory.com/do-see/sightse...owerpot-island

Aha, yes, so a dolomite top and softer limestone below. I wondered if this was the same arrangement that led to the Niagara Falls, but it seems not: that is dolomite over shale, apparently.

The Niagara Escarpment, of which I live on upper part, includes Flowerpot Island. Farthest most south points of ice age glaciers stretch a fair distance. Nearby where I am is the Niagara Gorge which is about 300' canyon carved by Niagara Falls as it moves towards Lake Erie. I'll assume the same rock that is here is also what makes up the Flowerpots though I don't see limestone on pic below. When you hike down the gorge you see massive boulders that have fallen in. Part of the path runs beneath a significant overhang near the top, makes me nervous every time I go there. Heard of dolomitic limestone, is that what we have here? Dolomite - limestone, same thing, almost?

Originally Posted by zinjanthropos

The Niagara Escarpment, of which I live on upper part, includes Flowerpot Island. Farthest most south points of ice age glaciers stretch a fair distance. Nearby where I am is the Niagara Gorge which is about 300' canyon carved by Niagara Falls as it moves towards Lake Erie. I'll assume the same rock that is here is also what makes up the Flowerpots though I don't see limestone on pic below. When you hike down the gorge you see massive boulders that have fallen in. Part of the path runs beneath a significant overhang near the top, makes me nervous every time I go there. Heard of dolomitic limestone, is that what we have here? Dolomite - limestone, same thing, almost?

Dolomite is harder, being a mixed salt of Ca/Mg CO3. But I wasn't crazy then to connect your Flowerpot Island to Niagara Falls, even if the strata look different under the dolomite cap. I think limestone can sometimes shade off into shales, as it is just a question of what was precipitated from the sea in different areas: CaCO3 or mud particles. Do you think the dolomite at Niagara is the same formation as at Flowerpot Island? (I visited the Falls once, by the way, in I think 1992, and walked along the gorge to take in how it was formed. Very interesting trip.)

All my life I’ve been told Niagara is sitting over an ancient sea and it’s primarily limestone. I was surprised not to see it on the cutaway diagram. Flowerpot Island is at best a 4 hr drive from my house to the boat launch. I’d say around 300-350 Km.