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Multiple shallow level sill intrusions coupled with hydromagmatic explosive eruptions marked the initial phase of Ferrar large igneous province magmatism in northern Victoria Land, Antarctica

Open-File Report 2007-1047-SRP-104

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DOI: 10.3133/ofr20071047SRP104

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Abstract

Field data gathered during GANOVEX IX (2005/2006) in Northern Victoria Land, Antarctica, indicate that volcaniclastic deposits of phreatomagmatic eruptions (so-called Exposure Hill Type events) are intercalated with fluvial deposits of Triassic-Jurassic age at two stratigraphic levels. Abundant scoriaceous spatter (locally welded) indicates a hawaiian/strombolian component. Breccia-filled diatremes, from which volcaniclastic deposits were sourced, are rooted in sills which intruded wet sediments. The deposits are thus subaerial expressions of initial Ferrar magmatism involving intrusion of multiple shallow-level sills. Due to magma-sediment interaction abundant clastic dikes are developed that intrude the sediments and sills. All igneous components in the volcaniclastic deposits are andesitic in composition, as are the chilled margins of the sills. They are more differentiated than the basaltic andesites of the younger effusive section of Kirkpatrick plateau lavas which in northern Victoria Land start with pillow lavas and small volume lava flows from volcanic necks.

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Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Multiple shallow level sill intrusions coupled with hydromagmatic explosive eruptions marked the initial phase of Ferrar large igneous province magmatism in northern Victoria Land, Antarctica
Series title:
Open-File Report
Series number:
2007-1047-SRP-104
DOI:
10.3133/ofr20071047SRP104
Year Published:
2007
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Description:
5 p.
Larger Work Type:
Report
Larger Work Subtype:
USGS Numbered Series
Larger Work Title:
Antarctica: A Keystone in a Changing World--Online Proceedings for the Tenth International Symposium on Antarctic Earth Sciences. Santa Barbara, California, U.S.A.--August 26 to September 1, 2007
Other Geospatial:
Antarctica
Additional Online Files(Y/N):
N