NanoSIMS analysis of organic carbon from the Tissint Martian meteorite: Evidence for the past existence of subsurface organic‐bearing fluids on Mars |
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| Authors: | Yangting Lin Ahmed El Goresy Sen Hu Jianchao Zhang Philippe Gillet Yuchen Xu Jialong Hao Masaaki Miyahara Ziyuan Ouyang Eiji Ohtani Lin Xu Wei Yang Lu Feng Xuchao Zhao Jing Yang Shin Ozawa |
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| Institution: | 1. Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, , Beijing, 100029 China;2. Bayerisches Geoinstitüt, Universit?t Bayreuth, , 95447 Bayreuth, Germany;3. EPFL, , CH‐1015 Lausanne, Switzerland;4. Institute of Mineralogy, Petrology and Economic Geology, Graduate School of Science, Tohoku University, , Sendai, 980‐8578 Japan;5. Institute of Geochemistry, CAS, , Guiyang, China;6. National Astronomical Observatories, CAS, , Beijing, China;7. Guangzhou Institute of Geochemistry, CAS, , Guangzhou, China |
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| Abstract: | Two petrographic settings of carbonaceous components, mainly filling open fractures and occasionally enclosed in shock‐melt veins, were found in the recently fallen Tissint Martian meteorite. The presence in shock‐melt veins and the deuterium enrichments (δD up to +1183‰) of these components clearly indicate a pristine Martian origin. The carbonaceous components are kerogen‐like, based on micro‐Raman spectra and multielemental ratios, and were probably deposited from fluids in shock‐induced fractures in the parent rock of Tissint. After precipitation of the organic matter, the rock experienced another severe shock event, producing the melt veins that encapsulated a part of the organic matter. The C isotopic compositions of the organic matter (δ13C = ?12.8 to ?33.1‰) are significantly lighter than Martian atmospheric CO2 and carbonate, providing a tantalizing hint for a possible biotic process. Alternatively, the organic matter could be derived from carbonaceous chondrites, as insoluble organic matter from the latter has similar chemical and isotopic compositions. The presence of organic‐rich fluids that infiltrated rocks near the surface of Mars has significant implications for the study of Martian paleoenvironment and perhaps to search for possible ancient biological activities on Mars. |
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