Aleutian Island Arc Magmagenesis: Geochemical Variability and U-Pb Dating of Zircons in Unalaska Volcanic and Plutonic Rocks

Arcs are important for understanding crustal development. This study focuses on Unalaska Island, an island in the Central-Eastern Aleutians. Plutonic and volcanic samples collected during a 1975-76 field excursion from the Unalaska Formation, Captains Bay Pluton and Shaler Pluton on Unalaska Island...

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Bibliographic Details
Main Author: Trim, Charelle
Language:English
Published: University of Florida 2017
Subjects:
alaska
aleutians
arcs
geochemistry
magmagenesis
volcanoes
Sedanka
Aleutian Island
Alaska
Online Access:http://ufdc.ufl.edu/UFE0051582/00001
Description
Summary:Arcs are important for understanding crustal development. This study focuses on Unalaska Island, an island in the Central-Eastern Aleutians. Plutonic and volcanic samples collected during a 1975-76 field excursion from the Unalaska Formation, Captains Bay Pluton and Shaler Pluton on Unalaska Island and plutons from nearby Sedanka Island. Major element, trace element and isotopic analyses were performed on these samples and the data was modeled and compared to other Central-Eastern Aleutian samples. Seven of the samples from Unalaska were also dated using U-Pb geochronology. Results show that the plutonic and volcanic rocks originated from a similar magma source and they both formed ca. 10 Ma. The implication of these results is that the volcanic rocks on Unalaska Island are the extrusive equivalent of the underlying plutons.

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