|
|
Reconstructing the central sector of the Cordilleran Ice Sheet
Dulfer, Helen Elizabeth ; Margold, Martin (advisor) ; Ely, Jeremy (referee) ; Nývlt, Daniel (referee)
The Quaternary Period (last 2.6 Ma) was a time of increased climate oscillation that resulted in the repeated growth and decay of Northern Hemispheric ice sheets. During this period the Cordilleran Ice Sheet (CIS) repeatedly covered mountainous western North America and attained a volume and area similar to the present-day Greenland Ice Sheet. At the Last Glacial Maximum (LGM) the CIS formed part of the North American Ice Sheet Complex (NAISC), coalescing with the Laurentide Ice Sheet east of the Rocky Mountains. However, the high relief bed and remote location mean there are few empirical constraints pertaining to the nature of ice sheet build-up and retreat in the central region of the CIS, in northern British Columbia, making it one of the least understood ephemeral Pleistocene ice sheets. In this thesis I use glacial geomorphology and quantitative dating techniques to reconstruct the advance of the CIS to its LGM position and subsequent retreat. I use high resolution remotely sensed data to create a detailed map of glacial landforms for the central sector of the CIS, beneath the local LGM ice divide (55řN to 60řN; paper I). Seven landform categories were mapped: ice flow parallel lineations, moraines (CIS outlet glacier moraines, Late Glacial moraines and moraines of unknown origin), meltwater...
|
guest ::
