thumbnail

Pillow basalts of the Angayucham terrane: oceanic plateau and island crust accreted to the Brooks Range

Journal of Geophysical Research

By:
, ,

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time
  • Download citation as: RIS

Abstract

The Angayucham Mountains (north margin of the Yukon-Koyukuk province) are made up of an imbricate stack of four to eight east-west trending, steeply dipping, fault slabs composed of Paleozoic, Middle to Late Triassic, and Early Jurassic oceanic upper crustal rocks. Field relations and geochemical characteristics of the basaltic rocks suggest that the fault slabs were derived from an oceanic plateau or island setting and were emplaced onto the Brooks Range continental margin. The basalts are variably metamorphosed to prehnite-pumpellyite and low-greenschist facies. Major element analyses suggest that many are hypersthene-normative olivine tholeiites. The Triassic and Jurassic basalts are geochemically most akin to modern oceanic plateau and island basalts. Field evidence also favors an oceanic plateau or island setting. The great composite thickness of pillow basalt probably resulted from obduction faulting, but the lack of fault slabs of gabbro or peridotite suggests that obduction faults did not penetrate below oceanic layer 2, a likely occurrence if layer 2 were anomalously thick, as in the vicinity of an oceanic island. -from Authors

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Pillow basalts of the Angayucham terrane: oceanic plateau and island crust accreted to the Brooks Range
Series title:
Journal of Geophysical Research
Volume
94
Issue:
B11
Year Published:
1989
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Geophysical Research