Basaltic rocks occur widely on the terrestrial planets and differentiated asteroids, including the asteroid 4 Vesta. We conducted a shock recovery experiment with decaying compressive pulses on a terrestrial basalt at Chiba Institute of Technology, Japan. The sample recorded a range of pressures, and shock physics modeling was conducted to add a pressure scale to the observed shock features. The shocked sample was examined by optical and electron microscopy, electron back-scattered diffractometry, and Raman spectroscopy. We found that localized melting occurs at a lower pressure (~10 GPa) than previously thought (>20 GPa). The shocked basalt near the epicenter represents shock degree C of a recently proposed classification scheme for basaltic eucrites and, as such, our results provide a pressure scale for the classification scheme. Finally, we estimated the total fraction of the basaltic eucrites classified as shock degree C to be ~15% by assuming the impact velocity distribution onto Vesta.
@article{arxiv.2212.10964,
title = {Experimentally shock-induced melt veins in basalt: Improving the shock classification of eucrites},
author = {Haruka Ono and Kosuke Kurosawa and Takafumi Niihara and Takashi Mikouchi and Naotaka Tomioka and Junko Isa and Hiroyuki Kagi and Takuya Matsuzaki and Hiroshi Sakuma and Hidenori Genda and Tatsuhiro Sakaiya and Tadashi Kondo and Masahiro Kayama and Mizuho Koike and Yuji Sano and Masafumi Murayama and Wataru Satake and Takafumi Matsui},
journal= {arXiv preprint arXiv:2212.10964},
year = {2023}
}
Comments
17 pages, 4 figures, 1 table, 1 supplementary Information, accepted for publication in Geophysical Research Letters