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Alpine Karst in the Mt. Castleguard-Columbia Icefield Area, Canadian Rocky Mountains
D. C. Ford
Arctic and Alpine Research
Vol. 3, No. 3 (Summer, 1971), pp. 239-252
Published by: INSTAAR, University of Colorado
Stable URL: http://www.jstor.org/stable/1550196
Page Count: 14
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Mt. Castleguard and an adjacent valley, Castleguard Meadows, are situated at the southeastern margin of the Columbia Icefield. The mountain and meadows are underlain by massive Middle Cambrian limestones with some shales and dolomite interbeds; the rocks dip gently southeast. They are well karstified and a close juxtaposition of karst, glacial, and periglacial erosion processes can be observed. Above 2,300 m karst features occur on surfaces recently abandoned by Neoglacial ice, and much meltwater evidently sinks underground beneath the extant glaciers. Outside of Neoglacial margins limestone surfaces are reduced to felsenmeer devoid of karst features. In tundra below 2,300 m shaft-type sinkholes and many varieties of karren occur. Sinkholes are aligned along shale contacts and the distal edges of terminal moraines and are randomly distributed elsewhere. Underground drainage developed in two phases. (1) Castleguard Cave drained part of the central Icefield area downdip to springs at 2,000 m. The cave is a single river passage, longer than 10 km and passing beneath Mt. Castleguard. It has vadose and phreatic erosional elements and is attributed to the last interglacial. (2) In late- or postglacial times, Castleguard Cave was abandoned and a new conduit developed beneath it. This discharges at the "Big Springs" at 1,740 m. Drainage of the northern Meadows and Mt. Castleguard is incorporated into this second system. Discharge of the Big Springs is comparable in magnitude to that of the meltriver of Saskatchewan Glacier, the largest valley glacier draining the Icefield. The area illustrates that karst groundwater circulation may be maintained and even initiated at the soles of temperate glaciers.