Environmental Sciences, asked by keirakaycat, 5 months ago

In northeastern Minnesota, the glaciers were thousands of feet thick and glacial scratches and striations show that the ice moved from north-to-south through the state. Ice alone is not very abrasive. Formulate a theory for the cause these striations in the volcanic basalt of the Minnesota bedrock.

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Answered by varsha5160
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Answer:

In northeastern Minnesota, the glaciers were thousands of feet thick and glacial scratches and striations show that the ice moved from north-to-south through the state. Ice alone is not very abrasive.

Answered by sujiss1605
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The glacial history of Minnesota is most defined since the onset of the last glacial period, which ended some 10,000 years ago. Within the last million years, most of the Midwestern United States and much of Canada were covered at one time or another with an ice sheet. This continental glacier had a profound effect on the surface features of the area over which it moved. Vast quantities of rock and soil were scraped from the glacial centers to its margins by slowly moving ice and redeposited as drift or till. Much of this drift was dumped into old preglacial river valleys, while some of it was heaped into belts of hills (terminal moraines) at the margin of the glacier. The chief result of glaciation has been the modification of the preglacial topography by the deposition of drift over the countryside. However, continental glaciers possess great power of erosion and may actually modify the preglacial land surface by scouring and abrading rather than by the deposition of the drift.

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