[B-CG08] [EE] 深宇宙と深海から挑む生命探査科学

[BCG08-03] 初期海洋への天体衝突に伴う岩石水反応の理解を目指した超高速岩石-水衝突実験

*西澤 学¹、松井 洋平¹、渋谷 岳造¹、須田 好¹、高井 研¹、矢野 創² (1.海洋研究開発機構、2.宇宙航空研究開発機構)

キーワード：海洋衝突、冥王代、水岩石反応

Chemical composition of the Hadean ocean would have affected prebiotic chemical evolution and subsequent metabolic evolution of early life. High temperature water-rock interaction during deep sea hydrothermal circulation would have been a key component determining the seawater chemistry in the Hadean. Further, water-rock interaction during oceanic impact of asteroids should have played a unique role in determining the chemical composition of the Hadean ocean because of i) much higher T-P condition of shock reaction than that of deep sea hydrothermal reaction and ii) the involvement in chemical reaction of undifferentiated asteroid materials that would have been absent in oceanic crust (e.g., metal iron). To better understand the role of high T-P water-rock interaction during oceanic impact on the early earth, we have newly established a methodology of experimental impact in an open system that can simulate the Pressure-Temperature path of oceanic impact most faithfully. In this meeting, we plan to report experimental results that rocky material impacted into liquid water at a velocity of 4-6 km/sec.