Geological and geodynamic investigations of Alaskan tectonics: Responses in the ancient and modern geologic records to oblique plate convergence
Stratigraphic, structural, and geophysical modeling studies focusing on both the Mesozoic and modern development of southern Alaska aid in understanding the nature of tectonic responses to oblique plate convergence. Analyses of the Lower to Upper (?) Cretaceous Kahiltna assemblage of the western Ala...
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ftpurdueuniv:oai:docs.lib.purdue.edu:dissertations-6862 2023-07-02T03:29:29+02:00 Geological and geodynamic investigations of Alaskan tectonics: Responses in the ancient and modern geologic records to oblique plate convergence Kalbas, James L Freed, Andrew M. 2006-01-01T08:00:00Z https://docs.lib.purdue.edu/dissertations/AAI3259996 ENG eng Purdue University https://docs.lib.purdue.edu/dissertations/AAI3259996 Theses and Dissertations Available from ProQuest Geology|Geophysics text 2006 ftpurdueuniv 2023-06-12T20:20:30Z Stratigraphic, structural, and geophysical modeling studies focusing on both the Mesozoic and modern development of southern Alaska aid in understanding the nature of tectonic responses to oblique plate convergence. Analyses of the Lower to Upper (?) Cretaceous Kahiltna assemblage of the western Alaska Range and the Upper Cretaceous Kuskokwim Group of the northern Kuskokwim Mountains provide a stratigraphic record of orogenic growth in southwestern Alaska. The Kahiltna assemblage records dominantly west-directed gravity-flow transport of sediment to the axis of an obliquely closing basin that made up the suture zone between the allochthonous Wrangellia composite terrane and the North American pericratonic margin. Stratigraphic, compositional, and geochronologic analyses suggest that submarine-fan systems of the Kahiltna basin were fed from the subearial suture zone and contain detrital grains derived from both allochthonous and pericratonic sources, thereby implying a relatively close proximity of the island-arc terrane to the North American margin by late Early Cretaceous time. In contrast, Upper Cretaceous strata exposed immediately west of the Kahiltna assemblage record marine deposition during a period of transition from island arc accretion to strike-slip tectonics. The new stratigraphic model presented here recognizes diverse bathyal- to shelfal-marine depositional systems within the Kuskokwim Group that represent distinctive regional sediment entry points to the basin. Collectively, these strata suggest that the Kuskokwim Group represents the waning stages of marine deposition in a long-lived intra-oceanic and continental margin basin. Geodynamic studies focus on the mechanics of contemporary fault systems in southern Alaska inboard of the collisional Yakutat microplate. Finite-element analyses predict that a poorly understood Holocene strike-slip fault in the St. Elias Mountains transfers shear from the Queen Charlotte fault northward to the Denali fault, thereby forming a continuous transform system ... Text alaska range Kuskokwim Yakutat Alaska Purdue University: e-Pubs Queen Charlotte ENVELOPE(-132.088,-132.088,53.255,53.255) |
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Purdue University: e-Pubs |
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language |
English |
topic |
Geology|Geophysics |
spellingShingle |
Geology|Geophysics Kalbas, James L Geological and geodynamic investigations of Alaskan tectonics: Responses in the ancient and modern geologic records to oblique plate convergence |
topic_facet |
Geology|Geophysics |
description |
Stratigraphic, structural, and geophysical modeling studies focusing on both the Mesozoic and modern development of southern Alaska aid in understanding the nature of tectonic responses to oblique plate convergence. Analyses of the Lower to Upper (?) Cretaceous Kahiltna assemblage of the western Alaska Range and the Upper Cretaceous Kuskokwim Group of the northern Kuskokwim Mountains provide a stratigraphic record of orogenic growth in southwestern Alaska. The Kahiltna assemblage records dominantly west-directed gravity-flow transport of sediment to the axis of an obliquely closing basin that made up the suture zone between the allochthonous Wrangellia composite terrane and the North American pericratonic margin. Stratigraphic, compositional, and geochronologic analyses suggest that submarine-fan systems of the Kahiltna basin were fed from the subearial suture zone and contain detrital grains derived from both allochthonous and pericratonic sources, thereby implying a relatively close proximity of the island-arc terrane to the North American margin by late Early Cretaceous time. In contrast, Upper Cretaceous strata exposed immediately west of the Kahiltna assemblage record marine deposition during a period of transition from island arc accretion to strike-slip tectonics. The new stratigraphic model presented here recognizes diverse bathyal- to shelfal-marine depositional systems within the Kuskokwim Group that represent distinctive regional sediment entry points to the basin. Collectively, these strata suggest that the Kuskokwim Group represents the waning stages of marine deposition in a long-lived intra-oceanic and continental margin basin. Geodynamic studies focus on the mechanics of contemporary fault systems in southern Alaska inboard of the collisional Yakutat microplate. Finite-element analyses predict that a poorly understood Holocene strike-slip fault in the St. Elias Mountains transfers shear from the Queen Charlotte fault northward to the Denali fault, thereby forming a continuous transform system ... |
author2 |
Freed, Andrew M. |
format |
Text |
author |
Kalbas, James L |
author_facet |
Kalbas, James L |
author_sort |
Kalbas, James L |
title |
Geological and geodynamic investigations of Alaskan tectonics: Responses in the ancient and modern geologic records to oblique plate convergence |
title_short |
Geological and geodynamic investigations of Alaskan tectonics: Responses in the ancient and modern geologic records to oblique plate convergence |
title_full |
Geological and geodynamic investigations of Alaskan tectonics: Responses in the ancient and modern geologic records to oblique plate convergence |
title_fullStr |
Geological and geodynamic investigations of Alaskan tectonics: Responses in the ancient and modern geologic records to oblique plate convergence |
title_full_unstemmed |
Geological and geodynamic investigations of Alaskan tectonics: Responses in the ancient and modern geologic records to oblique plate convergence |
title_sort |
geological and geodynamic investigations of alaskan tectonics: responses in the ancient and modern geologic records to oblique plate convergence |
publisher |
Purdue University |
publishDate |
2006 |
url |
https://docs.lib.purdue.edu/dissertations/AAI3259996 |
long_lat |
ENVELOPE(-132.088,-132.088,53.255,53.255) |
geographic |
Queen Charlotte |
geographic_facet |
Queen Charlotte |
genre |
alaska range Kuskokwim Yakutat Alaska |
genre_facet |
alaska range Kuskokwim Yakutat Alaska |
op_source |
Theses and Dissertations Available from ProQuest |
op_relation |
https://docs.lib.purdue.edu/dissertations/AAI3259996 |
_version_ |
1770274647043997696 |