| Autor: |
Hill, G. J., Wannamaker, P. E., Maris, V., Stodt, J. A., Kordy, M., Unsworth, M. J., Bedrosian, P. A., Wallin, E. L., Uhlmann, D. F., Ogawa, Y., Kyle, P. |
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| Zdroj: |
Nature Communications; 7/13/2022, Vol. 13 Issue 1, p1-10, 10p |
| Abstrakt: |
Erebus volcano, Antarctica, with its persistent phonolite lava lake, is a classic example of an evolved, CO2-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 CO2 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 H2O-rich subduction arc volcanoes, CO2-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. Episodic magma eruption and CO2 release to the atmosphere are controlled where two structural trends meet to cause dilatancy. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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