Paleomagnetic evidence for late Cenozoic glaciations in the Mackenzie Mountains of the Northwest Territories, Canada
The Mackenzie Mountains were affected by montane valley glaciers during the Pleistocene and peripherally by the Laurentide Ice Sheet during the last glaciation. In this paper we report on magnetostratigraphic dating and correlation of three sections recording Late Pliocene to Late Pleistocene glacia...
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crcansciencepubl:10.1139/e96-067 2023-12-17T10:30:36+01:00 Paleomagnetic evidence for late Cenozoic glaciations in the Mackenzie Mountains of the Northwest Territories, Canada Barendregt, R. W. Enkin, R. J. Baker, J. Duk-Rodkin, A. 1996 http://dx.doi.org/10.1139/e96-067 http://www.nrcresearchpress.com/doi/pdf/10.1139/e96-067 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 33, issue 6, page 896-903 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1996 crcansciencepubl https://doi.org/10.1139/e96-067 2023-11-19T13:38:52Z The Mackenzie Mountains were affected by montane valley glaciers during the Pleistocene and peripherally by the Laurentide Ice Sheet during the last glaciation. In this paper we report on magnetostratigraphic dating and correlation of three sections recording Late Pliocene to Late Pleistocene glaciations: Katherine Creek, Little Bear River, and Inlin Brook (located around 65°N, 127°W). Each section consists of a colluvial unit overlying a Pliocene pediment surface cut into Proterozoic or Paleozoic bedrock, or Tertiary gravel, which is in turn overlain by a stack of five, and in places six, montane tills, usually with soils developed at their surfaces, and capped by a Laurentide till. Normal and reversed magnetizations were recognized with single-domain magnetite as a dominant remanence carrier. The Katherine Creek section has a normally magnetized colluvium at its base, which is overlain by two reversed tills, succeeded by three normal tills. We interpret the top two tills to be of Brunhes age (< 780 ka) but argue that the lowermost normal till is of probable Olduvai age (ca. 1.8 Ma). The two underlying tills are of Matuyama age (2.6 Ma to 780 ka), and the colluvial base is assigned to the Gauss (3.5–2.6 Ma). The Little Bear River section exposes a stratigraphic record similar to that found at Katherine Creek. Only four units could be assigned a paleomagnetic polarity, the others yielding incoherent results. Paleosols on the first and second till units were reversed and normal, respectively, and the top till was normal. Thus there is clear evidence of an older (reversed) Pleistocene glaciation and a magnetostratigraphic record compatible with that found at Katherine Creek. Magnetic measurements from Inlin Brook gave largely incoherent results, with the exception of the surface (Laurentide) till, which is normal. The glacial history recorded in the Mackenzie Mountains correlates well with other studies carried out in the Cordillera. The large-scale changes in climate revealed in these terrestrial records ... Article in Journal/Newspaper glacier* Ice Sheet Mackenzie mountains Northwest Territories Canadian Science Publishing (via Crossref) Northwest Territories Canada Little Bear River ENVELOPE(-125.904,-125.904,64.917,64.917) Katherine Creek ENVELOPE(-127.384,-127.384,65.071,65.071) Inlin Brook ENVELOPE(-126.454,-126.454,64.233,64.233) Canadian Journal of Earth Sciences 33 6 896 903 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Barendregt, R. W. Enkin, R. J. Baker, J. Duk-Rodkin, A. Paleomagnetic evidence for late Cenozoic glaciations in the Mackenzie Mountains of the Northwest Territories, Canada |
topic_facet |
General Earth and Planetary Sciences |
description |
The Mackenzie Mountains were affected by montane valley glaciers during the Pleistocene and peripherally by the Laurentide Ice Sheet during the last glaciation. In this paper we report on magnetostratigraphic dating and correlation of three sections recording Late Pliocene to Late Pleistocene glaciations: Katherine Creek, Little Bear River, and Inlin Brook (located around 65°N, 127°W). Each section consists of a colluvial unit overlying a Pliocene pediment surface cut into Proterozoic or Paleozoic bedrock, or Tertiary gravel, which is in turn overlain by a stack of five, and in places six, montane tills, usually with soils developed at their surfaces, and capped by a Laurentide till. Normal and reversed magnetizations were recognized with single-domain magnetite as a dominant remanence carrier. The Katherine Creek section has a normally magnetized colluvium at its base, which is overlain by two reversed tills, succeeded by three normal tills. We interpret the top two tills to be of Brunhes age (< 780 ka) but argue that the lowermost normal till is of probable Olduvai age (ca. 1.8 Ma). The two underlying tills are of Matuyama age (2.6 Ma to 780 ka), and the colluvial base is assigned to the Gauss (3.5–2.6 Ma). The Little Bear River section exposes a stratigraphic record similar to that found at Katherine Creek. Only four units could be assigned a paleomagnetic polarity, the others yielding incoherent results. Paleosols on the first and second till units were reversed and normal, respectively, and the top till was normal. Thus there is clear evidence of an older (reversed) Pleistocene glaciation and a magnetostratigraphic record compatible with that found at Katherine Creek. Magnetic measurements from Inlin Brook gave largely incoherent results, with the exception of the surface (Laurentide) till, which is normal. The glacial history recorded in the Mackenzie Mountains correlates well with other studies carried out in the Cordillera. The large-scale changes in climate revealed in these terrestrial records ... |
format |
Article in Journal/Newspaper |
author |
Barendregt, R. W. Enkin, R. J. Baker, J. Duk-Rodkin, A. |
author_facet |
Barendregt, R. W. Enkin, R. J. Baker, J. Duk-Rodkin, A. |
author_sort |
Barendregt, R. W. |
title |
Paleomagnetic evidence for late Cenozoic glaciations in the Mackenzie Mountains of the Northwest Territories, Canada |
title_short |
Paleomagnetic evidence for late Cenozoic glaciations in the Mackenzie Mountains of the Northwest Territories, Canada |
title_full |
Paleomagnetic evidence for late Cenozoic glaciations in the Mackenzie Mountains of the Northwest Territories, Canada |
title_fullStr |
Paleomagnetic evidence for late Cenozoic glaciations in the Mackenzie Mountains of the Northwest Territories, Canada |
title_full_unstemmed |
Paleomagnetic evidence for late Cenozoic glaciations in the Mackenzie Mountains of the Northwest Territories, Canada |
title_sort |
paleomagnetic evidence for late cenozoic glaciations in the mackenzie mountains of the northwest territories, canada |
publisher |
Canadian Science Publishing |
publishDate |
1996 |
url |
http://dx.doi.org/10.1139/e96-067 http://www.nrcresearchpress.com/doi/pdf/10.1139/e96-067 |
long_lat |
ENVELOPE(-125.904,-125.904,64.917,64.917) ENVELOPE(-127.384,-127.384,65.071,65.071) ENVELOPE(-126.454,-126.454,64.233,64.233) |
geographic |
Northwest Territories Canada Little Bear River Katherine Creek Inlin Brook |
geographic_facet |
Northwest Territories Canada Little Bear River Katherine Creek Inlin Brook |
genre |
glacier* Ice Sheet Mackenzie mountains Northwest Territories |
genre_facet |
glacier* Ice Sheet Mackenzie mountains Northwest Territories |
op_source |
Canadian Journal of Earth Sciences volume 33, issue 6, page 896-903 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e96-067 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
33 |
container_issue |
6 |
container_start_page |
896 |
op_container_end_page |
903 |
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1785583591749582848 |