Evolution of Martian water reservoirs: constrants from meteorite analysis

2015 Fiscal Year Final Research Report

• Project/Area Number: 26800272
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Petrology/Mineralogy/Economic geology
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Tomohiro Usui 東京工業大学, 大学院理工学研究科, 助教 (60636471)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 火星 / 水 / 火星隕石 / 水素同位体

Outline of Final Research Achievements

We have provided accurate estimation of hydrogen isotope compositions (D/H) of Martian water reservoirs at the time when the meteorites formed. Based on the D/H datasets from Martian meteorites, we have estimated the amounts of water loss due to atmospheric escape and demonstrate that water loss during pre-Noachian was more significant than in the rest of the Martian history. Combining our results with geological and geomorphological evidence for ancient oceans, we propose a possibility that there should be undetected subsurface water/ice of much greater extent than the collective amounts of “visible” current water inventory. Our study further implies that, because such large water inventory automatically calls for significant water loss that cannot be explained by oxygen escape models, unknown mechanisms that effectively consume the remaining excess oxygen should be required.

Free Research Field

宇宙地球化学