Trans-crustal structural control of CO2-rich extensional magmatic systems revealed at Mount Erebus Antarctica

Graham J Hill; Phil E Wannamaker; Virginie Maris; J. A. Stodt; Michael Kordy; Martyn J. Unsworth; Paul A. Bedrosian; Erin L. Wallin; Danny F. Uhlmann; Yasuo Ogawa; Philip R. Kyle

doi:10.1038/s41467-022-30627-7

USGS · 70274304

Trans-crustal structural control of CO2-rich extensional magmatic systems revealed at Mount Erebus Antarctica

Graham J Hill·Phil E Wannamaker·Virginie Maris·J. A. Stodt·Michael Kordy·Martyn J. Unsworth·Paul A. Bedrosian·Erin L. Wallin·Danny F. Uhlmann·Yasuo Ogawa·Philip R. Kyle

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Abstract

Erebus volcano, Antarctica, with its persistent phonolite lava lake, is a classic example of an evolved, CO 2 -rich rift volcano. Seismic studies provide limited images of the magmatic system. Here we show using magnetotelluric data that a steep, melt-related conduit of low electrical resistivity originating in the upper mantle undergoes pronounced lateral re-orientation in the deep crust before reaching shallower magmatic storage and the summit lava lake. The lateral turn represents a structural fault-valve controlling episodic flow of magma and CO 2 vapour, which replenish and heat the high level phonolite differentiation zone. This magmatic valve lies within an inferred, east-west structural trend forming part of an accommodation zone across the southern termination of the Terror Rift, providing a dilatant magma pathway. Unlike H 2 O-rich subduction arc volcanoes, CO 2 -dominated Erebus geophysically shows continuous magmatic structure to shallow crustal depths of < 1 km, as the melt does not experience decompression-related volatile supersaturation and viscous stalling.

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Source-reported bounding extent: -78° to -77° latitude; 165° to 170° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Graham J Hill, Phil E Wannamaker, Virginie Maris, J. A. Stodt, Michael Kordy, Martyn J. Unsworth, Paul A. Bedrosian, Erin L. Wallin, Danny F. Uhlmann, Yasuo Ogawa, Philip R. Kyle. 2022-05-30. Trans-crustal structural control of CO2-rich extensional magmatic systems revealed at Mount Erebus Antarctica. https://doi.org/10.1038/s41467-022-30627-7

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