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Revised age of Aleutian island arc formation implies high rate of magma production

Brian R. Jicha, David W. Scholl, Brad S. Singer, Gene M. Yogodzinski and Suzanne M. Kay
Revised age of Aleutian island arc formation implies high rate of magma production
Geology (Boulder) (August 2006) 34 (8): 661-664

Abstract

Radioisotopic dating of subaerial and submarine volcanic and plutonic rocks from the Aleutian Island Arc provides insight into the timing of arc formation in the middle Eocene. Twenty-eight (super 40) Ar/ (super 39) Ar ages constrain the duration of arc magmatism to the last 46 m.y. Basaltic lavas from the Finger Bay volcanics, the oldest exposed rocks in the arc, gave an isochron age of 37.4+ or -0.6 Ma, which is 12-17 m.y. younger than a widely cited age of 55-50 Ma. Three main pulses of arc-wide magmatism occurred at 38-29, 16-11, and 6-0 Ma, which coincide with periods of intense magmatism in other western Pacific island arcs. Using the geochronology and volumetric estimates of crust generated and eroded over the last 46 m.y., we calculate a time-averaged magma production rate for the entire arc that exceeds previous estimates by almost an order of magnitude.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 34
Serial Issue: 8
Title: Revised age of Aleutian island arc formation implies high rate of magma production
Affiliation: University of Wisconsin, Department of Geology and Geophysics, Madison, WI, United States
Pages: 661-664
Published: 200608
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 30
Accession Number: 2006-062586
Categories: GeochronologyIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2006135
Illustration Description: sect., 2 tables, sketch map
N51°31'60" - N52°07'60", W176°58'60" - W176°25'60"
Secondary Affiliation: Stanford University, USA, United StatesUniversity of South Carolina, USA, United StatesCornell University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200635
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