S1: Earth materials science in igneous processes (Special Session)

11:45 AM - 12:00 PM JST(2:45 AM - 3:00 AM UTC)

[S1-08] TEM observation of microtexture of the groundmass pyroxene crystals in the ejecta of the Shinmoedake 2011 eruption<font color="#FF7F27">「発表賞エントリー」</font>

*Shota Okumura¹, Akira Miyake¹ (1. Kyoto Uni. Sci)

Keywords:

Pyroxene,Nanolite,Shinmoedake,TEM,Microtexture

In the ejecta of Shinmoedake 2011 eruption, groundmass pyroxene crystals have the composite texture of Opx and Cpx. We observed their microtexture by TEM. The diffraction patterns and STEM-EDS analysis reveal that Cpx (Aug, Pig) are attached to an Opx layer on both {100} planes with the same c-axis. The existence of the crystals with the twinning Cpx indicates epitaxial growth of Cpx. Although the crystals have a relatively wide range of composition, smaller crystals tend to be rich in Fe.