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Behrendt, J.C., Finn, C.A., Blankenship, D. and Bell, R.E. (1998). Aeromagnetic evidence for a volcanic caldera(?) Complex beneath the divide of the West Antarctic Ice Sheet. Geophysical Research Letters 25: doi: 10.1029/1998GL900101. issn: 0094-8276. |
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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. ¿ 1998 American Geophysical Union 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. ¿ 1998 American Geophysical Union |
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Abstract |
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Keywords
Geomagnetism and Paleomagnetism, Magnetic anomaly modeling, Volcanology |
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Publisher
American Geophysical Union
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