Aeromagnetic evidence for a volcanic caldera(?) complex beneath the divide of the West Antarctic Ice Sheet

Geophysical Research Letters
By: , and 

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Abstract

A 1995–96 aeromagnetic survey over part of the Sinuous Ridge (SR) beneath the West Antarctic Ice Sheet (WAIS) divide shows a 70-km diameter circular pattern of 400–1200-nT anomalies suggesting one of the largest volcanic caldera(?) complexes on earth. Radar-ice-sounding (RIS) shows the northern part of this pattern overlies the SR, and extends south over the Bentley Subglacial Trench (BST). Modeled sources of all but one the caldera(?) anomalies are at the base of <1–2-km thick ice and their volcanic edifices have been glacially removed. The exception is a 700-m high, 15-km wide "volcano" producing an 800-nT anomaly over the BST. “Intrusion” of this “volcano” beneath 3 km of ice probably resulted in pillow basalt rather than easily removed hyaloclastite erupted beneath thinner ice. The background area (−300 to −500-nT) surrounding the caldera(?) is possibly caused by a shallow Curie isotherm. We suggest uplift of the SR forced the advance of the WAIS.

Publication type Article
Publication Subtype Journal Article
Title Aeromagnetic evidence for a volcanic caldera(?) complex beneath the divide of the West Antarctic Ice Sheet
Series title Geophysical Research Letters
DOI 10.1029/1998GL900101
Volume 25
Issue 23
Year Published 1998
Language English
Publisher American Geophysical Union
Description 4 p.
First page 4385
Last page 4388
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