Strong water isotopic anomalies in the martian atmosphere: probing current and ancient reservoirs.
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.
NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA. Catholic University of America, Washington, DC 20064, USA. geronimo.villanueva@nasa.gov.
G L
GL
Villanueva
NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
M J
MJ
Mumma
Iona College, New Rochelle, NY 10801, USA.
R E
RE
Novak
European Southern Observatory, Munich, Germany.
H U
HU
Käufl
Max Planck Institute for Solar System Research, Katlenburg-Lindau 37191, Germany.
P
P
Hartogh
Observatoire de Paris-Meudon, Meudon 92195, France.
T
T
Encrenaz
University of Hawaii-Manoa, Honolulu, HI 96822, USA.
A
A
Tokunaga
University of Hawaii-Manoa, Honolulu, HI 96822, USA.
A
A
Khayat
NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
M D
MD
Smith
D001272:Atmosphere; D003903:Deuterium / Q000032:analysis; D017666:Deuterium Oxide; D019419:Evolution, Planetary; D005118:Extraterrestrial Environment; D007053:Ice; D018535:Mars; D014867:Water
D007053:Ice; D014867:Water; D003903:Deuterium; D017666:Deuterium Oxide