How do the erosive effects of rivers and glaciers compare in relation to degree and time?
Rivers, even large ones at flood, are not as big as glaciers. They move more quickly, although with great force. Relative to rivers, glaciers are huge, allowing them to affect larger areas; they move more slowly or ponderously than rivers. Large and small rocks, carried along by rivers, are rounded by the constant bouncing around in a river’s flow; whereas, rocks carried by glaciers show no evidence of polishing. The river’s flow sorts the deposits it makes at flood and at its alluvial plain, whereas the glacier simply carries the debris along, dropping it off in piles of unsorted rubble as it melts in retreat. • Are there any geologic features that could be created by either glaciers or rivers? Explain. ANSWER: Both create valleys but only glaciers create U-shaped valleys. Both create lakes but only glaciers create kettle ponds. Eskers, drumlins, kames and fjords could not have been the result of flowing water. • Explain to students that what is now understood to be definite evidence
