The Topographically Asymmetrical Alaska Range: Multiple Tectonic Drivers Through Space And Time
Dissertation (Ph.D.) University of Alaska Fairbanks, 2011 The topographically segmented, ~700 km long Alaska Range evolved over the last ~50 Ma in response to both far-field driving mechanisms and near-field boundary conditions. The eastern Alaska Range follows the curve of the Denali Fault strike-s...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/9070 2023-05-15T13:09:27+02:00 The Topographically Asymmetrical Alaska Range: Multiple Tectonic Drivers Through Space And Time Benowitz, Jeffrey Layer, Paul 2011 http://hdl.handle.net/11122/9070 unknown http://hdl.handle.net/11122/9070 Department of Geology and Geophysics Geology Plate tectonics Dissertation phd 2011 ftunivalaska 2023-02-23T21:37:11Z Dissertation (Ph.D.) University of Alaska Fairbanks, 2011 The topographically segmented, ~700 km long Alaska Range evolved over the last ~50 Ma in response to both far-field driving mechanisms and near-field boundary conditions. The eastern Alaska Range follows the curve of the Denali Fault strike-slip system, forming a large arc of high topography across southern Alaska. The majority of the topography in the eastern Alaska Range lies north of the Fault. A region of low topography separates the eastern Alaska Range from the central Alaska Range, where most of the high topography lies south of the Denali Fault. To the west, there is a restraining bend in the Fault. Southwest of the bend, the north-south trending western Alaska Range takes an abrupt 90 degree turn away from the Denali Fault. I applied 40Ar/39Ar thermochronology to over forty granitic samples to constrain the thermal history of the western and eastern Alaska Range. I combine the 40Ar/39Ar analyses with available apatite fission track and apatite (U-Th)/He dating. I then inferred the Alaska Range's exhumation history from the region's rates and patterns of rock cooling. Periods of mountain building within the Alaska Range are related to Paleocene-Eocene ridge subduction and an associated slab window (~50 Ma to ~35 Ma), Neogene flat-slab subduction of the Yakutat microplate (~24 Ma to present), Yakutat microplate latitudinal variation in thickness (~6 Ma to present), block rotation/migration, and fault reorganization along the Denali Fault. However, it is clear from basin, petrological and thermochronological constraints that not all of the far-field driving mechanisms affected every segment of the Alaska Range to the same degree or at the same time. Alaska Range tectonic reconstruction is also complicated by near-field structural controls on both the timing and extent of deformation. Fault geometry affects both the amount of exhumation (e.g., ~14 km in the Susitna Glacier region of the eastern Alaska Range) and location of topographic development ... Doctoral or Postdoctoral Thesis alaska range glacier Yakutat Alaska University of Alaska: ScholarWorks@UA Fairbanks |
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Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
unknown |
topic |
Geology Plate tectonics |
spellingShingle |
Geology Plate tectonics Benowitz, Jeffrey The Topographically Asymmetrical Alaska Range: Multiple Tectonic Drivers Through Space And Time |
topic_facet |
Geology Plate tectonics |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 2011 The topographically segmented, ~700 km long Alaska Range evolved over the last ~50 Ma in response to both far-field driving mechanisms and near-field boundary conditions. The eastern Alaska Range follows the curve of the Denali Fault strike-slip system, forming a large arc of high topography across southern Alaska. The majority of the topography in the eastern Alaska Range lies north of the Fault. A region of low topography separates the eastern Alaska Range from the central Alaska Range, where most of the high topography lies south of the Denali Fault. To the west, there is a restraining bend in the Fault. Southwest of the bend, the north-south trending western Alaska Range takes an abrupt 90 degree turn away from the Denali Fault. I applied 40Ar/39Ar thermochronology to over forty granitic samples to constrain the thermal history of the western and eastern Alaska Range. I combine the 40Ar/39Ar analyses with available apatite fission track and apatite (U-Th)/He dating. I then inferred the Alaska Range's exhumation history from the region's rates and patterns of rock cooling. Periods of mountain building within the Alaska Range are related to Paleocene-Eocene ridge subduction and an associated slab window (~50 Ma to ~35 Ma), Neogene flat-slab subduction of the Yakutat microplate (~24 Ma to present), Yakutat microplate latitudinal variation in thickness (~6 Ma to present), block rotation/migration, and fault reorganization along the Denali Fault. However, it is clear from basin, petrological and thermochronological constraints that not all of the far-field driving mechanisms affected every segment of the Alaska Range to the same degree or at the same time. Alaska Range tectonic reconstruction is also complicated by near-field structural controls on both the timing and extent of deformation. Fault geometry affects both the amount of exhumation (e.g., ~14 km in the Susitna Glacier region of the eastern Alaska Range) and location of topographic development ... |
author2 |
Layer, Paul |
format |
Doctoral or Postdoctoral Thesis |
author |
Benowitz, Jeffrey |
author_facet |
Benowitz, Jeffrey |
author_sort |
Benowitz, Jeffrey |
title |
The Topographically Asymmetrical Alaska Range: Multiple Tectonic Drivers Through Space And Time |
title_short |
The Topographically Asymmetrical Alaska Range: Multiple Tectonic Drivers Through Space And Time |
title_full |
The Topographically Asymmetrical Alaska Range: Multiple Tectonic Drivers Through Space And Time |
title_fullStr |
The Topographically Asymmetrical Alaska Range: Multiple Tectonic Drivers Through Space And Time |
title_full_unstemmed |
The Topographically Asymmetrical Alaska Range: Multiple Tectonic Drivers Through Space And Time |
title_sort |
topographically asymmetrical alaska range: multiple tectonic drivers through space and time |
publishDate |
2011 |
url |
http://hdl.handle.net/11122/9070 |
geographic |
Fairbanks |
geographic_facet |
Fairbanks |
genre |
alaska range glacier Yakutat Alaska |
genre_facet |
alaska range glacier Yakutat Alaska |
op_relation |
http://hdl.handle.net/11122/9070 Department of Geology and Geophysics |
_version_ |
1766177443409821696 |