GUMDROP HILL

The MonoMonday theme is Fact or Fiction. This is fact.
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Gumdrop Hill is a Moulin Kame...a feature of glacial geology in my area of the planet. Kames are formed as glaciers retreat...we know this because as glaciers advance, any object in the way gets plowed under and flattened. 
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As glaciers advance over rock, the rock gets ground into many small pieces the size of grains of sand all the way to the size of large boulders and everything in between. These rock pieces get plowed up in front of the moving mass of ice forming walls of gravel, moraines, but much of it gets incorporated into the ice mass itself.
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As temperatures warm and the glaciers start to melt, they obviously start to melt from the top down. The melt water finds its way through cracks in the ice and flows downward through the ice mass to the bottom, taking with it much of the incorporated gravel.
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Imagine sand flowing downward through an hour glass...you can see how it forms a symmetrical pile of sand at the bottom. This is how a kame is formed, as gravel flows, along with the water, through ice cracks as if through an hourglass.
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As the water slowly flows through the pile of gravel, forms rivers and flows away, the rocks remain and we see the pile of stones left as a kame.
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My area is rich in glacial formations as we exist in a valley between two separate lobes of the moving glacier. One lobe to the east flowed southward and scooped out the Lake Michigan basin. A separate lobe flowed south to the west of the Lake Michigan lobe and formed many moraines as it plowed up the substrate. We live in the valley between the lobes, the Interlobate Valley, and most kames are formed here as the glacier retreated. Also seen in the area are other glacial phenomena, eskers and drumlins, but that's another story.
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A photo of Gumdrop Hill is found in every textbook on glacial geology as it's the most perfectly formed kame ever found and there are not that many places in the world where these structures are located.

FYI.....if you measure the height of the geological phenomenon above the ground level, it's estimated that the ice above it was about 10X higher. For example, if a kame were 100 feet high, the ice that formed it would have been on the order of 1000 feet high.  It's estimated that the ice above the Lake Michigan basin would have been about two miles thick.
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Best in Large. The Extra is the color version for those who like that better.

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