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Hi Otsengotseng wrote:I don't doubt that such scraping exists. But could you cite your reference for this?goat wrote:New York is known for the fact that heavy galcerial activity happened there on multiple occations. You can go up in the mountains, and see sections of bedrock that have scraps on them that show the directoin of the flow of glaciers. These scrapes are formed as the glacier drags smaller rocks along their path.
http://en.wikipedia.org/wiki/Ice_age#Ev ... r_ice_agesGeological evidence for ice ages comes in various forms, including rock scouring and scratching, glacial moraines, drumlins, valley cutting, and the deposition of till or tillites and glacial erratics.
In this thread, I'm arguing that ribbed moraines and drumlins are the result of water action. And in the Scablands thread, it was shown that floods can form valley cutting and erratics. So, about the only thing left in terms of geological evidence are rock scratches.
If you rubbed two sheets of solids together, wouldn't it just result in a smooth surface rather than more bumps?Furrowed Brow wrote:Underneath the receding ice sheet there will be solids, and the ice is a solid, and by definition there is friction and movement, if you could speed up history, would you see the base of the ice sheet, though solid like the boulders in an avalanche, actually behaving much like a liquid.
Yes, ice can flow slowly.micatala wrote:Do we agree that ice can flow slowly (as in a glacier like goat's example)?
This is difficult to answer because the deck is stacked.Do drumlins and ribbed moraines occur anywhere where there hasn't been glaciation?
No, I have not presented my hypothesis yet. I'll post it in a separate posting.And, if I missed it in my initial perusal of the thread, my apologies, but do we have any alternate water-based explanation for creating these features at the scale we find them? If so, can we find any examples where evidence exists of these features being created by water not associated with ice?
And what exactly do you think MADE the lakes?? From answer.comotseng wrote:Below is a map of drumlin fields in the Great Lakes region.
http://www.geo.msu.edu/geo333/drumlins.html
The directionality of the drumlins are indicated on the map. I would say it's more consistent with water receding into the lakes, rather than glacier movement.
It is more evident on the map of the bottom of the page. (It's too large to include here)
The red lines indicate drumlins. If a large glacier formed the drumlins, shouldn't all the dumlins be parallel to each other? And how can drumlins at the bottom left go east-west?
A more reasonable explanation is that water receded from the land into the lake and is more consistent with the direction of the drumlins.
The Great Lakes were formed approximately at the end of the Pleistocene period, when the glacier-carved lake basins were filled with meltwater from the retreating ice sheet. The lakes are connected to each other by straits, short rivers, and canals. The height above sea level of the lake surfaces varies from Lake Superior's 602 ft (183 m) to Lake Ontario's 246 ft (75 m); the greatest sudden drop occurs at Niagara Falls (167 ft/51 m) between lakes Erie and Ontario; the water levels fluctuate over the months and years due to climatic changes. All the lake bottoms, except that of Lake Erie, extend below sea level.
http://en.wikipedia.org/wiki/Sand_Hills_%28Nebraska%29The Sand Hills are a 19,600 mi² (50,960 km²) region of mixed-grass prairie in north-central Nebraska, covering just over one-fourth of the state.
It seems quite ad hoc to me. Glaciers can carve out lakes and also on the shores leave drumlins. How is it able to do this?goat wrote:And what exactly do you think MADE the lakes?? From answer.com
The Great Lakes were formed approximately at the end of the Pleistocene period, when the glacier-carved lake basins were filled with meltwater from the retreating ice sheet. The lakes are connected to each other by straits, short rivers, and canals. The height above sea level of the lake surfaces varies from Lake Superior's 602 ft (183 m) to Lake Ontario's 246 ft (75 m); the greatest sudden drop occurs at Niagara Falls (167 ft/51 m) between lakes Erie and Ontario; the water levels fluctuate over the months and years due to climatic changes. All the lake bottoms, except that of Lake Erie, extend below sea level.
Can you find a geological paper that would confirm this?otseng wrote:It seems quite ad hoc to me. Glaciers can carve out lakes and also on the shores leave drumlins. How is it able to do this?goat wrote:And what exactly do you think MADE the lakes?? From answer.com
The Great Lakes were formed approximately at the end of the Pleistocene period, when the glacier-carved lake basins were filled with meltwater from the retreating ice sheet. The lakes are connected to each other by straits, short rivers, and canals. The height above sea level of the lake surfaces varies from Lake Superior's 602 ft (183 m) to Lake Ontario's 246 ft (75 m); the greatest sudden drop occurs at Niagara Falls (167 ft/51 m) between lakes Erie and Ontario; the water levels fluctuate over the months and years due to climatic changes. All the lake bottoms, except that of Lake Erie, extend below sea level.
A more simpler answer is that receding waters created the drumlins and filled the lower elevations with water to create the lakes.
Whether I have a geology degree or not is immaterial.goat wrote: Or, are you just speculating. I don't have a geology degree. DO you?
When a glacier advances, it acts like a bulldozer, however, because there is a lot of pressure on the bottom of the glacier, the bottom of the glacier is very fluid.otseng wrote:Whether I have a geology degree or not is immaterial.goat wrote: Or, are you just speculating. I don't have a geology degree. DO you?
All I ask is an explanation of the mechanism of how a glacier is able to carve out a lake and also leave drumlins.
