Origin of the late Eocene Eshamy suite granitoids of western Prince William Sound, Alaska
The geochronology and geochemistry of five Eshamy suite plutons in Prince William Sound, Alaska, tests the applicability of tectonic models explaining late Eocene magmatism in Prince William Sound with respect to the Sanak-Baranof plutons. Based on zircon U/Pb ages, the Sheep Bay pluton in eastern P...
Other Authors: | , , , |
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Language: | unknown |
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2012
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Subjects: |
Eocene Epoch
> Eocene magmatism
> Igneous rocks
> Inclusions
> Xenoliths
> Uranium-lead dating
> U-Pb
> Zircon
> Dating
> Nellie Juan River (Alaska)
> Plutons
> Igneous rocks
> Plutons
> Magmas
> Alaska
> Prince William Sound (Alaska)
> Alaska
> Eshamy bay
> Whitman College
> Dissertation collection 2012
> Geology-Chemistry
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Online Access: | http://works.whitman.edu/1130 |
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ftwhitmancollege:oai:arminda:arminda_61277 2023-05-15T17:54:01+02:00 Origin of the late Eocene Eshamy suite granitoids of western Prince William Sound, Alaska Johnson, Emily (Emily P Johnson) Kristen Nicolaysen Frank Dunnivant Geology 2012-05-09 http://works.whitman.edu/1130 unknown arminda:61277 http://works.whitman.edu/1130 context key: 8047126 If you have questions about permitted uses of this content, please contact the ARMINDA administrator http://rightsstatements.org/vocab/InC/1.0/ Eocene Epoch -- Eocene magmatism--Igneous rocks -- Inclusions -- Xenoliths--Uranium-lead dating -- U-Pb--Zircon -- Dating--Nellie Juan River (Alaska) -- Plutons--Igneous rocks -- Plutons--Magmas -- Alaska--Prince William Sound (Alaska)--Alaska -- Eshamy bay--Whitman College -- Dissertation collection 2012 -- Geology-Chemistry 2012 ftwhitmancollege 2020-12-20T17:42:08Z The geochronology and geochemistry of five Eshamy suite plutons in Prince William Sound, Alaska, tests the applicability of tectonic models explaining late Eocene magmatism in Prince William Sound with respect to the Sanak-Baranof plutons. Based on zircon U/Pb ages, the Sheep Bay pluton in eastern Prince William Sound (54.5 ±1.8 Ma) correlates with Sanak-Baranof plutonism (62-48 Ma); in contrast, Eshamy suite pluton ages range from 37.56 ±0.37 Ma to 39.91 ±0.66, requiring evaluation of a tectonic model to explain younger magmatism in the region. Subduction of a mid-ocean spreading center and subsequent formation of a slab window beneath the accretionary wedge and plate margin predicts anomalously high heat flow that will melt accretionary wedge sediments. These sediment melts may then mix with mantle-derived basalts to create the Eshamy suite plutons. The geochemistry of two Eshamy suite plutons, the Eshamy Bay and the Nellie Juan, shows three main results: 1) The Eshamy suite granites are heterogeneous and look similar to the Orca Group sediments in trace element chemistry but not in major element chemistry; 2) Xenoliths within Eshamy suite plutons have major element compositions between Pacific NMORB and the felsic granite end-member; 3) The Eshamy suite correlates with rhyolites and granitoids in the Caribou Creek Volcanic Field (CCVF) in trace element chemistry. The model of MOR subduction and slab window formation in response to Eocene plate reorganization as suggested by Cole et al. (2006) and Kusky et al. (2003) to explain the genesis of the CCVF rhyolites is a reasonable hypothesis to explain genesis of PWS pluton. Other/Unknown Material Orca Alaska Arminda @ Whitman College Pacific |
institution |
Open Polar |
collection |
Arminda @ Whitman College |
op_collection_id |
ftwhitmancollege |
language |
unknown |
topic |
Eocene Epoch -- Eocene magmatism--Igneous rocks -- Inclusions -- Xenoliths--Uranium-lead dating -- U-Pb--Zircon -- Dating--Nellie Juan River (Alaska) -- Plutons--Igneous rocks -- Plutons--Magmas -- Alaska--Prince William Sound (Alaska)--Alaska -- Eshamy bay--Whitman College -- Dissertation collection 2012 -- Geology-Chemistry |
spellingShingle |
Eocene Epoch -- Eocene magmatism--Igneous rocks -- Inclusions -- Xenoliths--Uranium-lead dating -- U-Pb--Zircon -- Dating--Nellie Juan River (Alaska) -- Plutons--Igneous rocks -- Plutons--Magmas -- Alaska--Prince William Sound (Alaska)--Alaska -- Eshamy bay--Whitman College -- Dissertation collection 2012 -- Geology-Chemistry Origin of the late Eocene Eshamy suite granitoids of western Prince William Sound, Alaska |
topic_facet |
Eocene Epoch -- Eocene magmatism--Igneous rocks -- Inclusions -- Xenoliths--Uranium-lead dating -- U-Pb--Zircon -- Dating--Nellie Juan River (Alaska) -- Plutons--Igneous rocks -- Plutons--Magmas -- Alaska--Prince William Sound (Alaska)--Alaska -- Eshamy bay--Whitman College -- Dissertation collection 2012 -- Geology-Chemistry |
description |
The geochronology and geochemistry of five Eshamy suite plutons in Prince William Sound, Alaska, tests the applicability of tectonic models explaining late Eocene magmatism in Prince William Sound with respect to the Sanak-Baranof plutons. Based on zircon U/Pb ages, the Sheep Bay pluton in eastern Prince William Sound (54.5 ±1.8 Ma) correlates with Sanak-Baranof plutonism (62-48 Ma); in contrast, Eshamy suite pluton ages range from 37.56 ±0.37 Ma to 39.91 ±0.66, requiring evaluation of a tectonic model to explain younger magmatism in the region. Subduction of a mid-ocean spreading center and subsequent formation of a slab window beneath the accretionary wedge and plate margin predicts anomalously high heat flow that will melt accretionary wedge sediments. These sediment melts may then mix with mantle-derived basalts to create the Eshamy suite plutons. The geochemistry of two Eshamy suite plutons, the Eshamy Bay and the Nellie Juan, shows three main results: 1) The Eshamy suite granites are heterogeneous and look similar to the Orca Group sediments in trace element chemistry but not in major element chemistry; 2) Xenoliths within Eshamy suite plutons have major element compositions between Pacific NMORB and the felsic granite end-member; 3) The Eshamy suite correlates with rhyolites and granitoids in the Caribou Creek Volcanic Field (CCVF) in trace element chemistry. The model of MOR subduction and slab window formation in response to Eocene plate reorganization as suggested by Cole et al. (2006) and Kusky et al. (2003) to explain the genesis of the CCVF rhyolites is a reasonable hypothesis to explain genesis of PWS pluton. |
author2 |
Johnson, Emily (Emily P Johnson) Kristen Nicolaysen Frank Dunnivant Geology |
title |
Origin of the late Eocene Eshamy suite granitoids of western Prince William Sound, Alaska |
title_short |
Origin of the late Eocene Eshamy suite granitoids of western Prince William Sound, Alaska |
title_full |
Origin of the late Eocene Eshamy suite granitoids of western Prince William Sound, Alaska |
title_fullStr |
Origin of the late Eocene Eshamy suite granitoids of western Prince William Sound, Alaska |
title_full_unstemmed |
Origin of the late Eocene Eshamy suite granitoids of western Prince William Sound, Alaska |
title_sort |
origin of the late eocene eshamy suite granitoids of western prince william sound, alaska |
publishDate |
2012 |
url |
http://works.whitman.edu/1130 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Orca Alaska |
genre_facet |
Orca Alaska |
op_relation |
arminda:61277 http://works.whitman.edu/1130 context key: 8047126 |
op_rights |
If you have questions about permitted uses of this content, please contact the ARMINDA administrator http://rightsstatements.org/vocab/InC/1.0/ |
_version_ |
1766161737735733248 |