Presentation Information
[R6P-09]Mineralogical occurrence of alunite-supergroup minerals in the 1895 CE eruption product at Zao Volcano, NE Japan
*Takumi Imura1, Masao Ban1, Tsukasa Ohba2 (1. Yamagata Univ. Sci., 2. Akita Univ.)
Keywords:
Alunite-supergroup minerals,Zao Volcano,Subvolcanic hydrothermal system,Lithic ash,Hydrothermal alteration
This study mineralogically investigated alunite-supergroup minerals in the clayish pyroclastic deposit from the 1895 CE magmatic-hydrothermal eruption in Zao Volcano. The subjected deposit is divided into six units (Layer 1 to Layer 6) based on increase of eruptive intensity with a sequence. Towards Layer 5 and 6, the alunite-supergroup minerals became dominant in huangite with natroalunite-2c. This trend represents the drastic change of the hydrothermal fluid sourced for the minerals, caused by a flux increase of the magmatic vapor separated from the1895 CE degassed magma.
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