Japan Geoscience Union Meeting 2022

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[J] Poster

S (Solid Earth Sciences ) » S-CG Complex & General

[S-CG47] Petrology, Mineralogy & Resource Geology

Thu. Jun 2, 2022 11:00 AM - 1:00 PM Online Poster Zoom Room (29) (Ch.29)

convener:Tatsuo Nozaki(Submarine Resources Research Center, Research Institute for Marine Resources Utilization, Japan Agency for Marine-Earth Science and Technology), convener:Yu Nishihara(Geodynamics Research Center Ehime University), Koichi Momma(National Museum of Nature and Science), convener:Yui Kouketsu(Department of Earth & Planetary Sciences, Graduate School of Environmental Studies, Nagoya University), Chairperson:Tatsuo Nozaki(Submarine Resources Research Center, Research Institute for Marine Resources Utilization, Japan Agency for Marine-Earth Science and Technology), Yu Nishihara(Geodynamics Research Center Ehime University), Koichi Momma(National Museum of Nature and Science), Yui Kouketsu(Department of Earth & Planetary Sciences, Graduate School of Environmental Studies, Nagoya University)

11:00 AM - 1:00 PM

[SCG47-P07] Partial melting texture observed in felsic rocks of Kajishima, Ehime Prefecture, Southwest Japan.

*Kazuya Shimooka1, Satoshi SAITO1 (1.Graduate School of Science and Engineering, Ehime University)


Keywords:Cretaceous igneous activity, Felsic dyke, Petrography, Kajishima, Flare-ups

We have carried out detailed petrographic study on the felsic rocks in Kajishima island, Ehime Prefecture, southwest Japan. The Kajishima island mainly consists of various types of gabbroids. Felsic dykes are locally distributed in the island. The felsic dykes are mainly composed of quartz, plagioclase, and biotite. They locally contain anhedral poikilitic K-feldspar containing corroded plagioclase, euhedral quartz, and euhedral to subhedral biotite (Fig. 1). The corroded plagioclase in the poikilitic K-feldspar is suggestive of partial melting (cf. Akasaki et al., 2015). Cathodoluminescence analysis of the euhedral quartz grains revealed that they contain irregular-shaped core, suggestive of discontinuous growth of quartz grain. The rim domain of quartz likely grew from the melt. Therefore, the poikilitic K-feldspar containing corroded plagioclase and euhedral quartz with irregular-shaped core probably indicates partial melting.

Reference: Akasaki et al. (2015) Lithos, 230, 82-91.