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Plutonic rocks of Jurassic age in the Alaska-Aleutian Range Batholith; chemical variations and polarity

Bruce L. Reed, Alfred T. Miesch and Marvin A. Lanphere
Plutonic rocks of Jurassic age in the Alaska-Aleutian Range Batholith; chemical variations and polarity
Geological Society of America Bulletin (October 1983) 94 (10): 1232-1240

Abstract

The plutonic rocks represent the roots of a magmatic arc. Tonalite and quartz diorite are the dominant rock types. Trend-surface analysis was used to examine the geographic variation of major oxides. If the chemical trends reflect the approximate geometry of a paleosubduction zone, the polarity of the Jurassic magmatic arc is to the northwest. The paleosubduction zone was on the northwest side of the arc, and subduction was directed toward the southeast. The paleosubduction zone is on the opposite side of the arc from the position that has generally been assumed, indicating that the Jurassic plutonic rocks were not generated in response to classical Andean-type convergent plate margins. The magmatic arc may have formed in an intra-ocean environment, and subsequently has been rafted northward and accreted to this part of the northern Pacific rim during the late Mesozoic.--Modified journal abstract.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 94
Serial Issue: 10
Title: Plutonic rocks of Jurassic age in the Alaska-Aleutian Range Batholith; chemical variations and polarity
Affiliation: U. S. Geol. Surv., Anchorage, AK, United States
Pages: 1232-1240
Published: 198310
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 63
Accession Number: 1983-056015
Categories: Igneous and metamorphic petrologyGeochemistry of rocks, soils, and sediments
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, geol. sketch map
N59°00'00" - N61°00'00", W154°30'00" - W151°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute.
Update Code: 1983
Program Name: USGSOPNon-USGS publications with USGS authors
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