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Intra-arc extension and magmatic evolution in the central Aleutian arc, Alaska

Bradley S. Singer and James D. Myers
Intra-arc extension and magmatic evolution in the central Aleutian arc, Alaska
Geology (Boulder) (November 1990) 18 (11): 1050-1053

Abstract

New geologic, petrologic, and Sr isotope data from Seguam Island, Alaska, reveal substantial variation in the composition of magmas of the central Aleutian arc. The data indicate that variable magmatic processes occur along the strike of the arc. Seguam is situated on extended arc crust and has erupted voluminous basalt and dacite. In contrast to basalt from adjacent volcanic centers atop unextended crust, which evolved by polybaric open-system crystallization, Seguam lavas crystallized at shallow levels under closed-system conditions. Seguam basalt therefore better reflects the character of its source materials than basalt erupted through unextended arc crust. We conclude that along-arc differences in the nature of crystallization were facilitated by changes in the thermal and density structure of the subarc litho-sphere caused by infra-arc extension.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 18
Serial Issue: 11
Title: Intra-arc extension and magmatic evolution in the central Aleutian arc, Alaska
Affiliation: Univ. Wyo., Dep. Geol. and Geophys., Laramie, WY, United States
Pages: 1050-1053
Published: 199011
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 26
Accession Number: 1990-058265
Categories: Igneous and metamorphic petrologyGeochemistry of rocks, soils, and sediments
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
N51°00'00" - N55°30'00", W161°00'00" - E172°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1990
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