Experimentally Shock‐Induced Melt Veins in Basalt: Improving the Shock Classification of Eucrites
Experimentally Shock‐Induced Melt Veins in Basalt: Improving the Shock Classification of Eucrites
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DOI：
10.1029/2022gl101009
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发表时间：
2022-12
影响因子：
5.2
通讯作者：
H. Ono;K. Kurosawa;T. Niihara;T. Mikouchi;N. Tomioka;J. Isa;H. Kagi;Takuya Matsuzaki;H. Sakuma;H. Genda;T. Sakaiya;T. Kondo;M. Kayama;M. Koike;Y. Sano;M. Murayama;W. Satake;T. Matsui
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作者：
H. Ono;K. Kurosawa;T. Niihara;T. Mikouchi;N. Tomioka;J. Isa;H. Kagi;Takuya Matsuzaki;H. Sakuma;H. Genda;T. Sakaiya;T. Kondo;M. Kayama;M. Koike;Y. Sano;M. Murayama;W. Satake;T. Matsui
玄武岩广泛存在于类地行星和分化的小行星上，包括小行星4灶神星。我们在日本千叶工业大学的陆地玄武岩上进行了衰减压缩脉冲的冲击恢复实验。样品记录了一系列的压力，并进行冲击物理建模，以增加一个压力尺度所观察到的冲击功能。通过光学和电子显微镜、电子背散射衍射法和拉曼光谱法检查冲击样品。我们发现，局部熔化发生在比以前认为的（>20 GPa）更低的压力（100 GPa）。震中附近的冲击玄武岩代表“冲击度C”最近提出的分类方案的玄武eucrites，因此，我们的研究结果提供了一个压力规模的分类方案。最后，我们通过假设撞击速度分布到灶神星上，估计被归类为冲击度C的玄武质eucrites的总分数为15%。
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 the 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.