Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis
New low-temperature thermochronology data from clastic sedimentary rocks in the northern Richardson Mountains, Canada, indicate significant exhumational cooling during late Eocene–early Oligocene time. Apatite (U-Th-Sm)/He (AHe) data were collected from 19 Proterozoic–Paleocene rocks across a 115 km...
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ftunivcalgary:oai:prism.ucalgary.ca:1880/114475 2023-08-27T04:08:48+02:00 Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis McKay, Ryan D. Enkelmann, Eva Hadlari, Thomas Hubbard, Stephen Eaton, David 2020-08-17 application/pdf http://hdl.handle.net/1880/114475 https://doi.org/10.11575/PRISM/39635 en English eng Graduate Studies Science University of Calgary McKay, R. D. (2020). Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis (Unpublished master thesis). University of Calgary, Calgary, AB. http://dx.doi.org/10.11575/PRISM/39635 http://hdl.handle.net/1880/114475 University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. thermochronology tectonics deformation Cordillera Geology master thesis 2020 ftunivcalgary https://doi.org/10.11575/PRISM/39635 2023-08-06T06:22:16Z New low-temperature thermochronology data from clastic sedimentary rocks in the northern Richardson Mountains, Canada, indicate significant exhumational cooling during late Eocene–early Oligocene time. Apatite (U-Th-Sm)/He (AHe) data were collected from 19 Proterozoic–Paleocene rocks across a 115 km transect. Eighty-eight single-grain AHe dates range from 300 ± 5 Ma to 16 ± 4 Ma but most dates (65%) range 56–24 Ma. AHe dates are generally younger than the stratigraphic ages, indicative of thermal resetting by burial. Additionally, zircon (U-Th)/He (ZHe) data were collected from two Jurassic sandstones. The ten ZHe dates range from 831 ± 12 Ma to 291 ± 4 Ma and are older than the stratigraphic age, which limits maximum burial to <160°C. Our results from thermal history modeling indicate three phases of cooling, during the Paleocene–early Eocene (>65–50 Ma), late Eocene–early Oligocene (40–30 Ma), and late Oligocene–early Miocene (30–15 Ma). Most samples were sensitive to cooling during the first and second phases, whereas the third phase is not as well constrained. The rocks were close to surface temperatures and below the sensitivity of AHe analysis since the early–middle Miocene. The results suggest a previously unrecognized phase of cooling and inferred deformation in the northern Richardson Mountains during late Eocene–early Oligocene time. Our findings contribute to previous work that recognizes Late Cenozoic deformation along the eastern margin of the Northern Cordillera, in the northeastern Brooks Range (e.g. O’Sullivan et al., 1993; 1998b) and in the Mackenzie Mountains (Enkelmann et al., 2019). We investigated the potential mechanisms of this widespread deformation and found that the exhumation may relate to kinematic changes of the North American plate relative to structural trends along the margin of the Northern Cordillera. Master Thesis Brooks Range Mackenzie mountains PRISM - University of Calgary Digital Repository Canada Richardson Mountains ENVELOPE(-136.171,-136.171,67.000,67.000) |
institution |
Open Polar |
collection |
PRISM - University of Calgary Digital Repository |
op_collection_id |
ftunivcalgary |
language |
English |
topic |
thermochronology tectonics deformation Cordillera Geology |
spellingShingle |
thermochronology tectonics deformation Cordillera Geology McKay, Ryan D. Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis |
topic_facet |
thermochronology tectonics deformation Cordillera Geology |
description |
New low-temperature thermochronology data from clastic sedimentary rocks in the northern Richardson Mountains, Canada, indicate significant exhumational cooling during late Eocene–early Oligocene time. Apatite (U-Th-Sm)/He (AHe) data were collected from 19 Proterozoic–Paleocene rocks across a 115 km transect. Eighty-eight single-grain AHe dates range from 300 ± 5 Ma to 16 ± 4 Ma but most dates (65%) range 56–24 Ma. AHe dates are generally younger than the stratigraphic ages, indicative of thermal resetting by burial. Additionally, zircon (U-Th)/He (ZHe) data were collected from two Jurassic sandstones. The ten ZHe dates range from 831 ± 12 Ma to 291 ± 4 Ma and are older than the stratigraphic age, which limits maximum burial to <160°C. Our results from thermal history modeling indicate three phases of cooling, during the Paleocene–early Eocene (>65–50 Ma), late Eocene–early Oligocene (40–30 Ma), and late Oligocene–early Miocene (30–15 Ma). Most samples were sensitive to cooling during the first and second phases, whereas the third phase is not as well constrained. The rocks were close to surface temperatures and below the sensitivity of AHe analysis since the early–middle Miocene. The results suggest a previously unrecognized phase of cooling and inferred deformation in the northern Richardson Mountains during late Eocene–early Oligocene time. Our findings contribute to previous work that recognizes Late Cenozoic deformation along the eastern margin of the Northern Cordillera, in the northeastern Brooks Range (e.g. O’Sullivan et al., 1993; 1998b) and in the Mackenzie Mountains (Enkelmann et al., 2019). We investigated the potential mechanisms of this widespread deformation and found that the exhumation may relate to kinematic changes of the North American plate relative to structural trends along the margin of the Northern Cordillera. |
author2 |
Enkelmann, Eva Hadlari, Thomas Hubbard, Stephen Eaton, David |
format |
Master Thesis |
author |
McKay, Ryan D. |
author_facet |
McKay, Ryan D. |
author_sort |
McKay, Ryan D. |
title |
Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis |
title_short |
Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis |
title_full |
Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis |
title_fullStr |
Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis |
title_full_unstemmed |
Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis |
title_sort |
cenozoic exhumation history of the northern richardson mountains: results from apatite and zircon (u-th-sm)/he analysis |
publisher |
Graduate Studies |
publishDate |
2020 |
url |
http://hdl.handle.net/1880/114475 https://doi.org/10.11575/PRISM/39635 |
long_lat |
ENVELOPE(-136.171,-136.171,67.000,67.000) |
geographic |
Canada Richardson Mountains |
geographic_facet |
Canada Richardson Mountains |
genre |
Brooks Range Mackenzie mountains |
genre_facet |
Brooks Range Mackenzie mountains |
op_relation |
McKay, R. D. (2020). Cenozoic exhumation history of the northern Richardson Mountains: Results from apatite and zircon (U-Th-Sm)/He analysis (Unpublished master thesis). University of Calgary, Calgary, AB. http://dx.doi.org/10.11575/PRISM/39635 http://hdl.handle.net/1880/114475 |
op_rights |
University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. |
op_doi |
https://doi.org/10.11575/PRISM/39635 |
_version_ |
1775349703185006592 |