the columbia ice field topographic map at http://www.jeffstopos.com/maps/083C03
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the columbia ice field topographic map at http://www.jeffstopos.com/maps/083C03
LAs are of interest to glaciologists and climatologists because 1) ELA is an indicator of a glaciers ng term mass balance and therefore is 'heath and 2 ELAs are like thermometers they go up systematically when it warms and down when it cools (precipitation can also have an effect, but for simplicity we consider temperature here) For the Canadian Rockies, for example, the last ice age caused a-7 reduction in annual average temperature, and moved the ELA down approximately 1000 m. Paleo-ELAs (old ELAs inferred from landforms) are used as a tool for determining temperatures of past ice ages. 6) Terrace Mountain is approximately 6 km due south of the Saskatchewan Glacier. Of the glacier- related landforms discussed in class lectures, what is Terrace Mountain most likely to be? (1 pt) a) a tarn; b) an outwash plain; c) a horn; d) a drumlin 7) Given your answer in #6, what does the presence of Terrace Mountain tell you about glacier ice in the area? (1 pt) a) nothing; b) ice thickness was once less; c) ice thickness was once greater; d) the glacier ice here is cold-based 8) Immediately north of Terrace Mountain, there is presently a small glacier. Of the types of alpine glaciers described in class, which is it? (1 pt) a) a valley glacier; b) a cirque glacier c a niche glacier; d) a piedmont glacier 9) Give two factors that might contribute to the persistence of this small glacier here, while most glaciers in the area at this elevation seem to be retreating or disappearing. (Hint: think about effects of direct sun on ablation, and avalanches on accumulation) (2 pts) 10) Castleguard Mountain lies 5 km to the west of Terrace Mountain. There are two beautiful but now abandoned terminal moraines on the SE side of Castleguard (look a few km SE from the marked summit). Both are cut by streams carrying meltwater. Once you have identified these old terminal moraines, estimate how far each of the two glaciers (actually small unnamed lobes of the ice field) has retreated since forming its terminal moraine. (2 pts) Move to the NW side of the Columbia Ice Field, and find the Columbia Glacier. It has large lateral moraines and a 2 km long meltwater lake at its snout. This, hy the way, is the very beginning of the Athabasca River. Meltwater released here ends up in the Arctic Ocean via Great Slave Lake and the Mackenzie River a long trip indeedExplanation / Answer
6 D Drumlin, it is an oval shaped hill, largely composed of glacial drift,formed beneath a glacier.
7 C Ice thickness was once greater on glacier.
8 C Niche glaciers are very small and occupy gullies and hollows in north facing slopes.
9 1 may be presence of tiny rocky material in small glaciers 2 because of katabatic winds 3 may be presence of some vegetation.
10 1 depending on the melting and flow of water course the movement of moraines will depend.if the distance is less the rate of melting is low and vice versa.
11 1 crevices are caused by thinning of ice. hence areas of heavy land slides moraines etc are the possible areas for crevices.
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