Pleistocene niche glaciers and proto-cirques, Cataract Creek valley, Tobacco Root Mountains, Montana
Pleistocene niche glaciers and proto-cirques, Cataract Creek valley, Tobacco Root Mountains, Montana (in United States contributions to Quaternary research--Internat. Assoc. Quaternary Research, 8th Cong., Paris, 1969)
Special Paper - Geological Society of America (1969) 123: 103-114
Two moraines were deposited by Pleistocene niche or slab glaciers that emanated from poorly developed cirques along the valley sides rather than by valley glaciers that emanated from well-formed cirques at elevations of >9000 feet. Niche or slab glaciers were formed in hollows at elevations of <8000 feet because hollows were hemmed in and orographically influenced by valley glaciers on the south and east and by the main mountain diviide on the north and west. The two valley glaciers generated a locally cold microclimate in the hollows, which were well-situated for accumulation of snow drifting across the nearby divide. The fortuitous position of these hollows during late Pleistocene resulted in incipient glacier formation at elevations lower than would be expected.