| Literature DB >> 25515119 |
P R Mahaffy1, C R Webster2, J C Stern3, A E Brunner4, S K Atreya5, P G Conrad3, S Domagal-Goldman3, J L Eigenbrode3, G J Flesch2, L E Christensen2, H B Franz6, C Freissinet7, D P Glavin3, J P Grotzinger8, J H Jones9, L A Leshin10, C Malespin11, A C McAdam3, D W Ming9, R Navarro-Gonzalez12, P B Niles9, T Owen13, A A Pavlov3, A Steele14, M G Trainer3, K H Williford2, J J Wray15.
Abstract
The deuterium-to-hydrogen (D/H) ratio in strongly bound water or hydroxyl groups in ancient martian clays retains the imprint of the water of formation of these minerals. Curiosity's Sample Analysis at Mars (SAM) experiment measured thermally evolved water and hydrogen gas released between 550° and 950°C from samples of Hesperian-era Gale crater smectite to determine this isotope ratio. The D/H value is 3.0 (±0.2) times the ratio in standard mean ocean water. The D/H ratio in this ~3-billion-year-old mudstone, which is half that of the present martian atmosphere but substantially higher than that expected in very early Mars, indicates an extended history of hydrogen escape and desiccation of the planet.Entities:
Year: 2014 PMID： 25515119 DOI： 10.1126/science.1260291
Source DB: PubMed Journal: Science ISSN： 0036-8075 Impact factor: 47.728