Magmas in collision: Rethinking chemical zonation in silicic magmas
- 1Alaska Volcano Observatory, Geophysical Institute, University of Alaska, Fairbanks, Alaska 99775, USA
- 2Alaska Volcano Observatory, Alaska Division of Geological and Geophysical Surveys, 794 University Avenue, Suite 200, Fairbanks, Alaska 99709, USA
Abstract
The heterogeneity of eruptions attributed to protracted fractionation in subvolcanic magma chambers may instead result from chamber recharge. The case of mafic magma intruding andesitic slush is recognized as giving rise to hybrid effusive eruptions such as at Unzen volcano, Japan, and Soufriere Hills volcano, Montserrat. We propose that zoned andesite-rhyolite explosive eruptions are the complement to mafic recharge, where the resident magma is also andesitic but the intruding magma is silicic.
Footnotes
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- Accepted April 24, 2000.
- Received January 11, 2000.
- Revision received April 17, 2000.
- Geological Society of America
