Reflection seismic investigations of the Canadian Beaufort Sea margin, Arctic Ocean
The seismic stratigraphy and sedimentary architecture of the Canadian Beaufort Sea margin are investigated using a comprehensive grid of two-dimensional seismic reflection data. Three cross-shelf troughs, representing locations of former ice streams draining a 1000 km-long section of the Laurentide...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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Scott Polar Research Institute
2014
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| Online Access: | https://doi.org/10.17863/CAM.14161 https://www.repository.cam.ac.uk/handle/1810/268049 |
| Summary: | The seismic stratigraphy and sedimentary architecture of the Canadian Beaufort Sea margin are investigated using a comprehensive grid of two-dimensional seismic reflection data. Three cross-shelf troughs, representing locations of former ice streams draining a 1000 km-long section of the Laurentide Ice Sheet (LIS), are examined: the Mackenzie, Amundsen Gulf and M'Clure Strait systems. These palaeo-ice streams operated during the last, Late Wisconsinan glacial maximum, as well as during a hitherto unknown number of earlier Quaternary glaciations. Their dynamics influenced past ice-sheet configuration and may have forced abrupt climate change through transport of ice and freshwater to the Arctic Ocean. The objectives of this work are to constrain the number of ice advances through each trough, to discuss the possible timing of these events, and to examine the impact of Quaternary glaciation on the continental shelf and slope. The implications of these data are discussed in relation to ice dynamics at the northwest LIS limit, the glacial history of the Canadian Beaufort Sea margin, and the geomorphological imprint of palaeo-ice streams. The number of Quaternary ice advances across the Canadian Beaufort Sea margin varies markedly between the Mackenzie Trough (two) and the Amundsen Gulf Trough (at least nine). The Mackenzie Trough was probably occupied by an ice stream during the Late Wisconsinan and either the Illinoian or Early Wisconsinan glaciation. The Amundsen Gulf ice stream was initiated earlier in the Quaternary. The architecture of the slope beyond the Mackenzie Trough reflects this comparatively short history of ice advance and lacks the progradational architecture and major glacialsedimentary depocentre that is characteristic of slopes seaward of high-latitude cross-shelf troughs. In contrast, trough-mouth fans ( of volumes -10,000 km.3 and -60,000 km3) are present beyond Amundsen Gulf and M'Clure Strait, respectively. The location of 75 High Arctic cross-shelf troughs is presented together with a ... |
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