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Petrology and isotopic composition of Quaternary basanites dredged from the Bering Sea continental margin near Navarin Basin

Canadian Journal of Earth Sciences

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Abstract

Quaternary basanites were recovered from the continental margin of the Bering Sea near Navarin Basin. The basanites are highly vesicular flow rock and hyaloclastites similar to other alkalic volcanic rocks erupted repeatedly during the last Cenozoic on islands in the Bering Sea region and in mainland Alaska. K-Ar ages for the basanites indicate at least two episodes of volcanism at about 1.1 and 0.4 Ma. Trace-element data indicate these alkalic lavas have been generated by small, but variable, amounts of partial melting of a metasomatized lherzolite source. The relativley primitive compositions (MgO >9%), presence of mantle-derived xenoliths in some alkalic lavas, and presence of forsteritic olivine with low CaO and high NiO suggest that magma rose rapidly from great depth without spending time in large, long-lived magma chambers. Alkalic volcanism apparently resulted from upwelling and decompressional melting of small isolated mantle diapirs in response to local lithospheric attenuation associated with jostling of blocks during adjustment to regional stresses. -from Authors

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Petrology and isotopic composition of Quaternary basanites dredged from the Bering Sea continental margin near Navarin Basin
Series title:
Canadian Journal of Earth Sciences
Volume
30
Issue:
5
Year Published:
1993
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Canadian Journal of Earth Sciences
First page:
975
Last page:
984
Number of Pages:
10