Publication Date:
2019-07-13
Description:
We measured maps of atmospheric water (H2O) and its deuterated form (HDO) across the martian globe, showing strong isotopic anomalies and a significant high deuterium/hydrogen (D/H) enrichment indicative of great water loss. The maps sample the evolution of sublimation from the north polar cap, revealing that the released water has a representative D/H value enriched by a factor of about 7 relative to Earth's ocean [Vienna standard mean ocean water (VSMOW)]. Certain basins and orographic depressions show even higher enrichment, whereas high-altitude regions show much lower values (1 to 3 VSMOW). Our atmospheric maps indicate that water ice in the polar reservoirs is enriched in deuterium to at least 8 VSMOW, which would mean that early Mars (4.5 billion years ago) had a global equivalent water layer at least 137 meters deep.
Keywords:
Lunar and Planetary Science and Exploration
Type:
GSFC-E-DAA-TN31203
,
Science (ISSN 1095-9203); 348; 6231; 218-221
Format:
text
