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Paleogene geology and chronology of southwestern Umnak Island, Aleutian Islands, Alaska ( USA).

Canadian Journal of Earth Sciences

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Abstract

A slightly deformed marine sedimentary sequence reflecting volcanic arc sedimentation from late Eocene to early Oligocene is intruded by hypabyssal quartz diorite sills and small plutons with apparent ages of about 30 Ma, ie, middle Oligocene. Chemical data from igneous rocks exhibit calc-alkaline and tholeiitic volcanic arc differentiation trends. The fossil ages and radiometric dates from SW Umnak Island are similar to those reported from other central and E Aleutian islands, and indicate uniformity in the chronology and tectonic development of the archipelago during the Paleogene. Paleomagnetic data suggest possible northward movement but remain equivocal and more work is indicated. -after Authors

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Paleogene geology and chronology of southwestern Umnak Island, Aleutian Islands, Alaska ( USA).
Series title:
Canadian Journal of Earth Sciences
Volume
21
Issue:
2
Year Published:
1984
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Canadian Journal of Earth Sciences
First page:
171
Last page:
180