2022 Fiscal Year Final Research Report

Martian organics have still preserved in Black Beauty?

Research Project

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Project/Area Number	19K14780
Research Category	Grant-in-Aid for Early-Career Scientists
Allocation Type	Multi-year Fund
Review Section	Basic Section 17010:Space and planetary sciences-related
Research Institution	Japan Synchrotron Radiation Research Institute (2020-2022) The University of Tokyo (2019)
Principal Investigator	Suga Hiroki 公益財団法人高輝度光科学研究センター, 分光推進室, 研究員 (70827568)
Project Period (FY)	2019-04-01 – 2023-03-31
Keywords	火星隕石 / 有機物 / 水-岩石相互作用 / STXM / STEM / NanoSIMS / SFXM / 顕微分光
Outline of Final Research Achievements	This study aims to find organic matter derived from the Martian surface in the Martian basaltic breccia meteorite called Black Beauty (NWA 7034) to elucidate its formation and evolution processes. Meteorite samples polished under organic contamination-controlled conditions were analyzed by the combined microanalytical techniques based on SEM-FIB-STXM-TEM-NanoSIMS to obtain the morphology, distribution, chemical composition, and isotopes of organic matter in the Black Beauty. As a result, organic matter was found in two distributions: encapsulated in mineral grains and isolated distribution in the matrix. Those in minerals showed characteristics of organic matter thought to originate from volcanic activity on Mars, similar to the MMC found in the SNC meteorites. On the other hand, the organic matter in the matrix was considered to be Martian surface-related organics isotopically; they contained fine minerals formed by the aqueous alteration process in the Martian surface environment.
Free Research Field	惑星科学、地球化学、放射光、
Academic Significance and Societal Importance of the Research Achievements	過去には水が疑いなく存在したとされる火星における有機物の存在やその特徴付けは、火星での生命発生の可能性を探る手掛かりであり、今後の生命存在可能性（ハビタビリティー）を議論する上でも非常に重要な知見となる。本研究が国際誌に掲載されれば、「火星の表層同位体情報を有する有機物を火星隕石から明確に見つけ出して特徴づけした」世界で初めての成果となる。また将来、火星表層試料が地球へ帰還して実験室や放射光施設で詳細な分析が行われた際には、本研究で特徴づけられたマトリクス中の有機物（δ13C = 15 ± 7 ‰、δD = 373 ± 68 ‰）が実際の帰還試料から見つかってくるだろう。