Which is evidence that an area was once covered by a glacier?

Answer 1

Evidence a region was (or just as importantly, was not) covered by glaciers usually comes in the form of such glacial features as

• moraines
• cirques
• "erratics" (rocks moved from one place to another)
  
• glacial tarns
• most especially wide, U-shaped valleys with stepped stream gradients
• deep coastal fjords
• absence of deep sediment and short distance to bedrock
  

Even in very cold climates, these features are different from those found in central and northern Alaska, Siberia and Manchuria. We know that central and northern Alaska, eastern Siberia, most of Mongolia, and Manchuria were never covered by glaciers because of such features as V-shaped valleys, concave stream gradients and most importantly the deep sediment in their soils.

The reason Siberia, Manchuria, central and northern Alaska, and also the Patagonian steppes, were not glaciated during the Quaternary is simply that they were too dry. Except for the Patagonian steppes, all these regions are even today cold enough for glaciers, but so little snow fell and falls that even with much reduced ablation glaciers cannot develop. (For instance, Barrow receives only 29 inches of snow whereas glaciated Nunavik receives over 100.)

In hot regions, soils are so weathered it clear that glaciers could never have formed since the Carboniferous even if there is no deep sedimentation.

Answer 2

Scratched and polished bedrock; unsorted gravel deposits; transported boulders.

Ice sheet = Glacier

When you see "Scratched and polished" automatically think "glacier"

Answer 3

U- shaped valleys