TY - JOUR T1 - Early oxidation of the martian crust triggered by impacts A1 - Deng,Zhengbin A1 - Moynier,Frederic A1 - Villeneuve,Johan A1 - Jensen,Ninna K. A1 - Liu,Deze A1 - Cartigny,Pierre A1 - Mikouchi,Takashi A1 - Siebert,Julien A1 - Agranier,Arnaud A1 - Chaussidon,Marc A1 - Bizzarro,Martin AD - Univ Paris, Inst Phys Globe Paris, CNRS, F-75005 Paris, France. AD - Univ Lorraine, CRPG UMR 7350, CNRS, F-7358 Vandoeuvre Les Nancy, France. AD - Univ Copenhagen, Ctr Star & Planet Format, Globe Inst, Copenhagen, Denmark. AD - Univ Tokyo, Univ Museum, Tokyo, Japan. AD - Univ Bretagne Occident, Lab Geosci Ocean, UMR CNRS 6538, Plouzane, France. AD - Inst Univ Europe Mer, Plouzane, France. UR - https://archimer.ifremer.fr/doc/00686/79855/ DO - 10.1126/sciadv.abc4941 N2 - Despite the abundant geomorphological evidence for surface liquid water on Mars during the Noachian epoch (>3.7 billion years ago), attaining a warm climate to sustain liquid water on Mars at the period of the faint young Sun is a long-standing question. Here, we show that melts of ancient mafic clasts from a martian regolith meteorite, NWA 7533, experienced substantial Fe-Ti oxide fractionation. This implies early, impact-induced, oxidation events that increased by five to six orders of magnitude the oxygen fugacity of impact melts from remelting of the crust. Oxygen isotopic compositions of sequentially crystallized phases from the clasts show that progressive oxidation was due to interaction with an O-17-rich water reservoir. Such an early oxidation of the crust by impacts in the presence of water may have supplied greenhouse gas H-2 that caused an increase in surface temperature in a CO2-thick atmosphere. Y1 - 2020/10 PB - Amer Assoc Advancement Science JF - Science Advances SN - 2375-2548 VL - 6 IS - 44 ID - 79855 ER -