Pennsylvanian pluton stitching of Wrangellia and the Alexander Terrane, Wrangell Mountains, Alaska

M. C Gardner; S. C Bergman; G. W Cushing; E. M MacKevett; George Plafker; R. B Campbell; C. J Dodds; W. C McClelland; Paul A Mueller

doi:10.1130/0091-7613(1988)016<0967:PPSOWA>2.3.CO;2

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Pennsylvanian pluton stitching of Wrangellia and the Alexander Terrane, Wrangell Mountains, Alaska

Journal article

Peer reviewed

Pennsylvanian pluton stitching of Wrangellia and the Alexander Terrane, Wrangell Mountains, Alaska

M. C Gardner, S. C Bergman, G. W Cushing, E. M MacKevett, George Plafker, R. B Campbell, C. J Dodds, W. C McClelland and Paul A Mueller

Geology (Boulder), Vol.16(11), pp.967-971

11/1988

DOI: 10.1130/0091-7613(1988)016<0967:PPSOWA>2.3.CO;2

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Abstract

A quartz monzonite-syenite-alkali granite plutonic complex in eastern Alaska crosscuts the contact of the Alexander terrane and Wrangellia and intrudes the basement rocks of both terranes. Zircon U-Pb data indicate an intrusion age of 309 + or -5 Ma (Middle Pennsylvanian) for the pluton, and (super 40) K- (super 40) Ar age data for hornblende separates indicate cooling to about 450 degrees C during Middle Pennsylvanian-Early Permian time. The new field relations and age data demonstrate that Wrangellia and the Alexander terrane were contiguous during the Middle Pennsylvanian. This conclusion provides an important new constraint on paleogeographic reconstructions of the northwest Cordillera, and necessitates reassessment of stratigraphic and paleomagnetic data that were cited as evidence that the terranes evolved separately until the late Mesozoic.

absolute age

age

Alaska

Alexander Terrane

alkali granites

amphibole group

Carboniferous

chain silicates

clinoamphibole

contact metamorphism

dates

eastern Alaska

Geochronology

granites

hornblende

Igneous and metamorphic petrology

igneous rocks

intrusions

K/Ar

metamorphism

Middle Pennsylvanian

nesosilicates

orthosilicates

paleogeography

Paleozoic

Pennsylvanian

plutonic rocks

plutons

quartz monzonite

silicates

Southern Alaska

Structural geology

syenites

tectonics

terranes

thermal history

U/Pb

United States

Wrangell Mountains

Wrangellia

zircon

zircon group

Details

Title: Subtitle: Pennsylvanian pluton stitching of Wrangellia and the Alexander Terrane, Wrangell Mountains, Alaska
Creators: M. C Gardner - Southern California Gas Company
S. C Bergman - Southern California Gas Company
G. W Cushing - Southern California Gas Company
E. M MacKevett - 1230 Bayview Heights Drive, Los Osos, California 93402
George Plafker - United States Geological Survey
R. B Campbell - Geological Survey of Canada
C. J Dodds - Geological Survey of Canada
W. C McClelland - University of Arizona
Paul A Mueller - University of Florida
Resource Type: Journal article
Publication Details: Geology (Boulder), Vol.16(11), pp.967-971
Publisher: Geological Society of America (GSA)
DOI: 10.1130/0091-7613(1988)016<0967:PPSOWA>2.3.CO;2
ISSN: 0091-7613
eISSN: 1943-2682
Language: English
Date published: 11/1988
Academic Unit: Earth and Environmental Sciences
Record Identifier: 9984229165702771

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