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Aeromagnetic evidence for a volcanic caldera(?) Complex beneath the divide of the West Antarctic Ice Sheet
Author(s) -
Behrendt John C.,
Finn Carol A.,
Blankenship Donald,
Bell Robin E.
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1998gl900101
Subject(s) - geology , caldera , volcano , ice sheet , ridge , seismology , antarctic ice sheet , geomorphology , cryosphere , paleontology , oceanography , sea ice
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.