Study of bound water in the surface

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Study of bound water in the surface layer of Mars
Alexander T. Basilevsky
Vernadsky Institute of Geochemistry and
Analytical Chemistry Russian Acedemy of
Science Moscow 119991 Russia atbas_at_geokhi.ru
Workshop HEND-2002 The First year of HEND
operations on the NASA Odyssey Mars Orbiter May
20-22, 2002 Institute for Space Research Moscow,
Russia
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Bound water - water incorporated into minerals
and rocks which can not be removed without
changing structure or composition of these
materials.
Minerals H2O content Gypsum - 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
Rocks Basalt - volcanic rock with 44-50 SiO2
0.1 to 2 Andesite - volcanic rock with
53-63 SiO2 1-4 Rhyolite - volcanic rock
with gt68 SiO2 3-7 -------------------------
---- Clays of platforms of Earth
4-6 ---------------------------- Martian soil
(Viking GS-MS estimate) up to 1
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Bound water in tholeitic basalts of intra-plate
hot spots, Earth
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Water on Mars Noachian Period -Warm and wet or
cold and dry?
Viking image of cratered terrain with valley
network
If it was water, it should be chemically
incorporated into weathering products and
sediments and its hydrogen may potentially be
seen in HEND data
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Water on Mars Hesperian Period - Outflow
channels - water or liquid CO2
Viking image of Mars Pathfinder site at the mouth
of Ares Vallis
If it was water, their deposits may contain
H2O-OH-bearing minerals and their hydrogen may
potentially be seen in HEND data
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Water on Mars Hesperian Period - Did aqueous
ocean exist on Mars?
Mola topography map of Mars. Courtesy of Mola Team
If yes, its sediments should contain
H2O-OH-bearing minerals and their hydrogen may
potentially be seen in HEND data
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Water on Mars Amazonian Period Was liquid water
on and near the surface?
MOC image of gullies on the walls of crater
Kaiser (46.5S, 341.4W).
If yes, surface deposits may contain
H2O-OH-bearing minerals and their hydrogen may
potentially be seen in HEND data
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Impact-induced and magmatic hydrothermal activity
Amount 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
Mammoth Terrace
Norris Geiser
Courtesy of Elizabeth Tritthart, West Yellowstone
Web Works
Bedrock Rhyolite (Bauer, 1948 Browny, 1978)
Hydrothermal deposits Travertine CaCO3,
Geiserite SiO2 High-silica zeolites,
Clays
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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
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General approach - To correlate HEND data
with a) bedrock geology b) topography and c)
surface roughness
a)
Geologic map of Mars. Tanaka et al., 1978
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General approach - To correlate HEND data
with a) bedrock geology b) topography and c)
surface roughness
b)
Mola topography map of Mars. Courtesy of MOLA Team
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General approach - To correlate HEND data
with a) bedrock geology b) topography and c)
surface roughness
c)
Map of kilometer roughness of Mars. Kreslavsky
and Head, 2000
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HEND data (0.4 eV-100 keV)
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HEND v.s. bedrock geology
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HEND v.s. MOLA topography
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HEND v.s. MOLA km-scale roughness
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Discussion and conclusions

• Some correlation of HEND measured neutron flux
• with 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 show
• low H contents, same as materials of close
  vicinities

More analysis needed to reach meaningful
conclusions
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HEND data (0.4 eV-100 keV)
HEND data (1-7 MeV)
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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?