study of bound water in the surface layer of mars workshop hend-2002 “the first year of hend...
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Study of bound water in the surface layer of Mars
Workshop HEND-2002“The First year of HEND operations on the NASA Odyssey Mars Orbiter”
May 20-22, 2002Institute for Space Research
Moscow, Russia
Vernadsky Institute of Geochemistry and Analytical Chemistry
Russian Acedemy of ScienceMoscow 119991 Russia
Alexander T. Basilevsky
Bound water - water incorporated into minerals and rocks which can not be removed without changing structure or composition of these materials.
Minerals H2O contentGypsum - CaSO4 2H2O 21%Goethite - FeO (OH) 10%Nontronite
- Na0.33Fe23+(Al0.33Si3.67)O10 (OH)2 nH2O 5-15%
Chlorite - (Mg,Fe2+,Fe3+)6AlSi3O10(OH)8 5-14%Serpentine - (MgFe)3Si2O5(OH)4 10-13%Hornblende - (Ca,Na)2-3 (Mg,Fe2+,Fe3+,Al)5 (Al,Si)8 (OH)2 2-3%
RocksBasalt - volcanic rock with 44-50% SiO2 0.1 to 2%Andesite - volcanic rock with 53-63% SiO2 1-4%Rhyolite - volcanic rock with >68% SiO2 3-7%-----------------------------
Clays of platforms of Earth 4-6%----------------------------
Martian soil (Viking GS-MS estimate) up to 1%
Bound water in tholeitic basalts of intra-plate hot spots, Earth
Water on Mars: Noachian Period -Warm and wet or cold and dry?
If it was water, it should be chemically incorporated into weatheringproducts and sediments and its hydrogen may potentially be seen
in HEND data
Viking image of cratered terrain with valley network
Water on Mars: Hesperian Period- Outflow channels - water or liquid CO2
If it was water, their deposits may contain H2O-OH-bearing mineralsand their hydrogen may potentially be seen in HEND data
Viking image of Mars Pathfinder site at the mouth of Ares Vallis
Water on Mars: Hesperian Period- Did aqueous ocean exist on Mars?
If yes, its sediments should contain H2O-OH-bearing mineralsand their hydrogen may potentially be seen in HEND data
Mola topography map of Mars. Courtesy of Mola Team
Water on Mars: Amazonian PeriodWas liquid water on and near the surface?
If yes, surface deposits may contain H2O-OH-bearing mineralsand their hydrogen may potentially be seen in HEND data
MOC image of gullies on the walls of crater Kaiser (46.5S, 341.4W).
Impact-induced and magmatic hydrothermal activityAmount of impact-induced and magmatic hydrothermal
mineralization decreases with depth (Masaitis & Naumov, 1993). Should be most prominent on the surface. Possible (magmatic)
analog: Hydrothermal deposits of Yellowstone National Park
Bedrock: Rhyolite (Bauer, 1948; Browny, 1978) Hydrothermal deposits: Travertine CaCO3, Geiserite SiO2
High-silica zeolites, Clays…
Courtesy of Elizabeth Tritthart, West Yellowstone Web Works
Mammoth Terrace Norris Geiser
How to search for bound water? - To study areas where seasonal/perrenial ices/frosts are not expected: Equatorial zone for all seasons and mid-latitudes at summer
Mola shaded relief map of Mars. Courtesy of MOLA Team
General approach: - To correlate HEND data with a) bedrock geology
b) topography and c) surface roughness
Geologic map of Mars. Tanaka et al., 1978
a)
General approach: - To correlate HEND data with a) bedrock geology
b) topography and c) surface roughness
Mola topography map of Mars. Courtesy of MOLA Team
b)
Map of kilometer roughness of Mars. Kreslavsky and Head, 2000
General approach: - To correlate HEND data with a) bedrock geology
b) topography and c) surface roughness
c)
HEND data: (0.4 eV-100 keV)
HEND v.s. bedrock geology
HEND v.s. MOLA topography
HEND v.s. MOLA km-scale roughness
Discussion and conclusions
Some correlation of HEND measured neutron fluxwith geologic structures of Mars is seen:• Syrtis Major Planitia (more H, hyps. higher)
v.s Isidis Planitia (less H, hyps. lower) • Hellas basin floor (more H, hyps. lower)
v.s. Argyre basin floor (less H, hyps higher)• Noachian-Hesperian cratered terrain within 0-40W, 30N-15S
has highest contents of H among all equatorial zone,being usual in hypsometry and surface roughness
• Medusa Fossae: increase in H content comparing to surrounding areas
• Elysium Fossae: increase in H content comparing to Elysium Mons and its other surroundings
• Olympus, Arsia, Pavonis, Ascreus volcanic constructs showlow H contents, same as materials of close vicinities
More analysis needed to reach meaningful conclusions
HEND data: (0.4 eV-100 keV)
HEND data: (1-7 MeV)
Needs for future studies
• To understand meaning of neutron flux of different energies in the geological context (likbez)
• To have HEND results maps in cylindical projection
• To work on different gradations of the flux intensity categories on the maps
• To play with degree of smoothening on the maps
• Calibration of the results in percent of H2O
• Possibility of improvement of spatial resolution due to multiple overlapping of the measuring orbits?