Coalescence of late Wisconsinan Cordilleran and Laurentide ice sheets east of the Rocky Mountain Foothills in the Dawson Creek region, northeast British Columbia, Canada
| Autor: | Victor M. Levson, A S Hickin, Olav B. Lian |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
010506 paleontology
geography geography.geographical_feature_category Ice stream Glacier 010502 geochemistry & geophysics Glacier morphology 01 natural sciences Ice shelf Paleontology Arts and Humanities (miscellaneous) Ice core Ice age Wisconsin glaciation General Earth and Planetary Sciences Ice sheet Geomorphology Geology 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Quaternary Research. 85:409-429 |
| ISSN: | 1096-0287 0033-5894 |
| Popis: | Geomorphic, stratigraphic and geochronological evidence from northeast British Columbia (Canada) indicates that, during the late Wisconsinan (approximately equivalent to marine oxygen isotope stage [MIS] 2), a major lobe of western-sourced ice coalesced with the northeastern-sourced Laurentide Ice Sheet (LIS). High-resolution digital elevation models reveal a continuous 75 km-long field of streamlined landforms that indicate the ice flow direction of a major northeast-flowing lobe of the Cordilleran Ice Sheet (CIS) or a montane glacier (>200 km wide) was deflected to a north-northwest trajectory as it coalesced with the retreating LIS. The streamlined landforms are composed of till containing clasts of eastern provenance that imply that the LIS reached its maximum extent before the western-sourced ice flow crossed the area. Since the LIS only reached this region in the late Wisconsinan, the CIS/montane ice responsible for the streamlined landforms must have occupied the area after the LIS withdrew. Stratigraphy from the Murray and Pine river valleys supports a late Wisconsinan age for the surface landforms and records two glacial events separated by a non-glacial interval that was dated to be of middle Wisconsinan (MIS 3) age. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|