2021 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)

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Oral presentation

R7: Petrology, Mineralogy and Economic geology (Joint Session with Society of Resource Geology)

Sat. Sep 18, 2021 9:30 AM - 12:15 PM Zoom Session 3

Chairperson:Takuya Echigo(秋田大学), Norikatsu Akizawa(Atmosphere and Ocean Research Institute, The Univ. Tokyo)

11:15 AM - 11:30 AM

[R7-08] Geology and Au mineralization of the Hata deposit, Akita, Japan

*Yuki Konuma1, Yasushi Watanabe1, Takuya Echigo1 (1. Akita Uni. In.)

Keywords:epithermal Au deposit, low sulfidation, base metal sulfide, barite, sea water

A fieldwork of the geology of the Hata deposit and description of the ores revealed that the lower part of the deposit is rich in Au and rich in argentite in quartz veins with small amounts of barite. SEM-EDS analysis showed that the deposit is a low-sulfidation system where HS- and gold are complexed, and a epithermal deposit. XRD results show sericite and K-eldspar alteration. The fO2-pH diagram shows that the precipitation was caused by a decrease in the solubility of gold due to an increase in the partial pressure of oxygen in the hydrothermal.