Problem 2
Studies have shown that during the Ice Age, the margins of some ice sheets advanced southward from the Hudson Bay region at rates ranging from about 50 to 320 meters per year. a. Determine the maximum amount of time required for an ice sheet to move from the southern end of Hudson Bay to the south shore of present day Lake Erie, a distance of 1600 kilometers. b. Calculate the minimum number of years required for an ice sheet to move this distance.
Problem 3
What are the evidences of glacial and interglacial cyclicality during the Ice Age? What theory ean explain the existence of glaciers before that period? What phenomenon can explain the occurrence of glaciations during the Ice Age?
Problem 5
While taking a break from a hike in the Northern Rockies with a fellow geology enthusiast, you notice that the boulder you are sitting on is part of a deposit consisting of a jumbled mixture of unsorted sediment. Since you are in an area that once had extensive valley glaciers, your colleague suggests that the deposit must be glacial till. Although you know this is certainly a good possibility, you remind your companion that other processes in mountain areas also produce unsorted deposits. What might such a process be? How might you and your friend determine whether this deposit is actually glacial till?
Problem 7
If the budget of a valley glacier were balanced for an extended time span, what feature would you expect to find at the terminus of the glacier? Is it composed of till or stratified drift? Now assume that the glacier's budget changes so that ablation exceeds accumulation. How would the terminus of the glacier change? Describe the deposit you would expect to form under these conditions.
Problem 10
This wall, located in New England, is built of diverse stones and boulders cleared from nearby fields. In 1914 , Robert Frost wrote a nowfamous poem titled "Mending Wall" about a feature like this one. It begins with these lines: Something there is that doesn't love a wall, That sends the frozen-ground- swell under it, And spills the upper boulders in the sun; And makes gaps even two can pass abreast. a. What is the likely weathering process causing the wall to swell and "spill" its boulders? (Think back to Chapter 6 .) b. Is it likely that the source of all the rocks in the wall is bedrock in the immediate vicinity? Explain. c. What term applies to the rocks composing the wall?
Problem 13
Why do glacial deposits show poor sorting?
