The impact of climate and tectonics on sedimentary and deformational processes, Gulf of Alaska
text Collision of the Yakutat Terrane with North America in southern Alaska has driven growth of the Chugach-St. Elias orogen. Glaciation of the St. Elias Range has periodically increased since the Miocene, but began dominating erosion and spurred enhanced exhumation since the mid-Pleistocene transi...
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ftunivtexas:oai:repositories.lib.utexas.edu:2152/22281 2023-05-15T16:22:37+02:00 The impact of climate and tectonics on sedimentary and deformational processes, Gulf of Alaska Reece, Robert Sherman Gulick, Sean P. S. December 2012 application/pdf http://hdl.handle.net/2152/22281 en_US eng http://hdl.handle.net/2152/22281 Terrane Fan Glaciers Tectonics Mass-transport Farfield Collision Channel Gulf of Alaska Surveyor 2012 ftunivtexas 2020-12-23T22:18:14Z text Collision of the Yakutat Terrane with North America in southern Alaska has driven growth of the Chugach-St. Elias orogen. Glaciation of the St. Elias Range has periodically increased since the Miocene, but began dominating erosion and spurred enhanced exhumation since the mid-Pleistocene transition at ~1 Ma. Ice associated with this glacial intensification carved cross-shelf sea valleys that connect the St. Elias Range to the deep-sea Surveyor Fan. A newly increased terrigenous sediment flux into the fan triggered the formation and growth of the Surveyor Channel. The change in geomorphology observed throughout Fan sequences allows us to characterize the influence that a glaciated orogen can have in shaping margin processes and the sediment pathways from source to sink. Seismic data also reveal an isolated, large, short runout, mass-transport deposit (MTD) buried in the Surveyor Fan. The MTD geometry, size and location on a convergent margin lend support to recent studies suggesting seismic strengthening and infrequent sediment failure on active margins. This study provides insight into the magnitude and scope of events required to cause submarine mega-slides and overcome higher than normal sediment shear strength, including the influence of climate and sea level change. Beneath the Surveyor Fan, integrated geophysical data reveals massive intraplate shearing, and a lack of oceanic crust magnetic lineaments in regions of Pacific Plate crust. We argue that stress from the Yakutat-North America collision transferred outboard to the Pacific Plate is the major driver for the deformation causing these features. This stress would have resulted in significant strain in the NE corner of the Pacific Plate, creating pathways for sill formation in the crust and Surveyor Fan. The collision further intensified as the thickest Yakutat portion began to subduct during the Pleistocene, possibly providing the impetus for the creation of the Gulf of Alaska Shear Zone, a >200 km zone of shear extending out into the Pacific Plate. This study highlights the importance of farfield stress from complex tectonic regimes in consideration of large-scale oceanic intraplate deformation. Geological Sciences Other/Unknown Material glaciers Yakutat Alaska The University of Texas at Austin: Texas ScholarWorks Gulf of Alaska Pacific |
institution |
Open Polar |
collection |
The University of Texas at Austin: Texas ScholarWorks |
op_collection_id |
ftunivtexas |
language |
English |
topic |
Terrane Fan Glaciers Tectonics Mass-transport Farfield Collision Channel Gulf of Alaska Surveyor |
spellingShingle |
Terrane Fan Glaciers Tectonics Mass-transport Farfield Collision Channel Gulf of Alaska Surveyor Reece, Robert Sherman The impact of climate and tectonics on sedimentary and deformational processes, Gulf of Alaska |
topic_facet |
Terrane Fan Glaciers Tectonics Mass-transport Farfield Collision Channel Gulf of Alaska Surveyor |
description |
text Collision of the Yakutat Terrane with North America in southern Alaska has driven growth of the Chugach-St. Elias orogen. Glaciation of the St. Elias Range has periodically increased since the Miocene, but began dominating erosion and spurred enhanced exhumation since the mid-Pleistocene transition at ~1 Ma. Ice associated with this glacial intensification carved cross-shelf sea valleys that connect the St. Elias Range to the deep-sea Surveyor Fan. A newly increased terrigenous sediment flux into the fan triggered the formation and growth of the Surveyor Channel. The change in geomorphology observed throughout Fan sequences allows us to characterize the influence that a glaciated orogen can have in shaping margin processes and the sediment pathways from source to sink. Seismic data also reveal an isolated, large, short runout, mass-transport deposit (MTD) buried in the Surveyor Fan. The MTD geometry, size and location on a convergent margin lend support to recent studies suggesting seismic strengthening and infrequent sediment failure on active margins. This study provides insight into the magnitude and scope of events required to cause submarine mega-slides and overcome higher than normal sediment shear strength, including the influence of climate and sea level change. Beneath the Surveyor Fan, integrated geophysical data reveals massive intraplate shearing, and a lack of oceanic crust magnetic lineaments in regions of Pacific Plate crust. We argue that stress from the Yakutat-North America collision transferred outboard to the Pacific Plate is the major driver for the deformation causing these features. This stress would have resulted in significant strain in the NE corner of the Pacific Plate, creating pathways for sill formation in the crust and Surveyor Fan. The collision further intensified as the thickest Yakutat portion began to subduct during the Pleistocene, possibly providing the impetus for the creation of the Gulf of Alaska Shear Zone, a >200 km zone of shear extending out into the Pacific Plate. This study highlights the importance of farfield stress from complex tectonic regimes in consideration of large-scale oceanic intraplate deformation. Geological Sciences |
author2 |
Gulick, Sean P. S. |
author |
Reece, Robert Sherman |
author_facet |
Reece, Robert Sherman |
author_sort |
Reece, Robert Sherman |
title |
The impact of climate and tectonics on sedimentary and deformational processes, Gulf of Alaska |
title_short |
The impact of climate and tectonics on sedimentary and deformational processes, Gulf of Alaska |
title_full |
The impact of climate and tectonics on sedimentary and deformational processes, Gulf of Alaska |
title_fullStr |
The impact of climate and tectonics on sedimentary and deformational processes, Gulf of Alaska |
title_full_unstemmed |
The impact of climate and tectonics on sedimentary and deformational processes, Gulf of Alaska |
title_sort |
impact of climate and tectonics on sedimentary and deformational processes, gulf of alaska |
publishDate |
2012 |
url |
http://hdl.handle.net/2152/22281 |
geographic |
Gulf of Alaska Pacific |
geographic_facet |
Gulf of Alaska Pacific |
genre |
glaciers Yakutat Alaska |
genre_facet |
glaciers Yakutat Alaska |
op_relation |
http://hdl.handle.net/2152/22281 |
_version_ |
1766010618261798912 |