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

[S1-08] TEM observation of microtexture of the groundmass pyroxene crystals in the ejecta of the Shinmoedake 2011 eruption

「発表賞エントリー」

*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.