Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska

Igneous rocks in the Chugach metamorphic complex (CMC) of southern Alaska form part of the Sanak-Baranof belt, a series of forearc plutons believed to have been formed by subduction of a spreading ridge. Trace element and Nd-Sr isotopic data suggest that magmas were derived from the mixing of two so...

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Bibliographic Details
Main Author: Poole, Anne Rebecca
Format: Thesis
Language:English
Published: 1997
Subjects:
Geology
glacier
Yakutat
Alaska
Online Access:https://hdl.handle.net/1911/17124
id ftriceuniv:oai:scholarship.rice.edu:1911/17124
record_format openpolar
spelling ftriceuniv:oai:scholarship.rice.edu:1911/17124 2023-05-15T16:20:34+02:00 Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska Poole, Anne Rebecca 1997 application/pdf https://hdl.handle.net/1911/17124 eng eng Poole, Anne Rebecca. "Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska." (1997) Master’s Thesis, Rice University. https://hdl.handle.net/1911/17124 . https://hdl.handle.net/1911/17124 THESIS GEOL. 1997 POOLE Geology Thesis Text 1997 ftriceuniv 2022-08-09T20:32:12Z Igneous rocks in the Chugach metamorphic complex (CMC) of southern Alaska form part of the Sanak-Baranof belt, a series of forearc plutons believed to have been formed by subduction of a spreading ridge. Trace element and Nd-Sr isotopic data suggest that magmas were derived from the mixing of two sources: melted accretionary wedge sediments and mafic material underplated at the base of the wedge as the ridge was subducted. Metabasaltic amphibolites at Yakutat Bay found to be derived directly from material of MORB composition are further evidence that this underplated mafic source existed. Ridge migration along the Alaskan margin was generally towards the east. However, new U-Pb and $\sp{40}$Ar/$\sp{39}$Ar geochronology data show that within the CMC this movement was probably complicated by the subduction of a transform, causing the locus of magmatism to appear to jump from Van Cleve Glacier to Yakutat Bay at 54 Ma. Thesis glacier Yakutat Alaska Rice University: Digital Scholarship Archive
institution Open Polar
collection Rice University: Digital Scholarship Archive
op_collection_id ftriceuniv
language English
topic Geology
spellingShingle Geology
Poole, Anne Rebecca
Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska
topic_facet Geology
description Igneous rocks in the Chugach metamorphic complex (CMC) of southern Alaska form part of the Sanak-Baranof belt, a series of forearc plutons believed to have been formed by subduction of a spreading ridge. Trace element and Nd-Sr isotopic data suggest that magmas were derived from the mixing of two sources: melted accretionary wedge sediments and mafic material underplated at the base of the wedge as the ridge was subducted. Metabasaltic amphibolites at Yakutat Bay found to be derived directly from material of MORB composition are further evidence that this underplated mafic source existed. Ridge migration along the Alaskan margin was generally towards the east. However, new U-Pb and $\sp{40}$Ar/$\sp{39}$Ar geochronology data show that within the CMC this movement was probably complicated by the subduction of a transform, causing the locus of magmatism to appear to jump from Van Cleve Glacier to Yakutat Bay at 54 Ma.
format Thesis
author Poole, Anne Rebecca
author_facet Poole, Anne Rebecca
author_sort Poole, Anne Rebecca
title Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska
title_short Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska
title_full Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska
title_fullStr Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska
title_full_unstemmed Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska
title_sort age and geochemical constraints on ridge subduction for igneous rocks of the eastern chugach mountains, alaska
publishDate 1997
url https://hdl.handle.net/1911/17124
genre glacier
Yakutat
Alaska
genre_facet glacier
Yakutat
Alaska
op_relation Poole, Anne Rebecca. "Age and geochemical constraints on ridge subduction for igneous rocks of the eastern Chugach Mountains, Alaska." (1997) Master’s Thesis, Rice University. https://hdl.handle.net/1911/17124 .
https://hdl.handle.net/1911/17124
THESIS GEOL. 1997 POOLE
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