Compositional study of the putative chloride-bearing materials with OMEGA/MEx data and implications on their relationship with phyllosilicates

Details Compositional study of the putative chloride-bearing materials with OMEGA/MEx data and implications on their relationship with phyllosilicates Compositional study of the putative chloride-bearing materials with OMEGA/MEx data and implications on their relationship with phyllosilicates

Dec 2011

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufm.p22a..05r&link_type=abstract

American Geophysical Union, Fall Meeting 2011, abstract #P22A-05

Mathematics

Logic

[5410] Planetary Sciences: Solid Surface Planets / Composition, [6225] Planetary Sciences: Solar System Objects / Mars

Scientific paper

Daytime infrared images of the Mars Odyssey Thermal Emission Imaging System (THEMIS) have been used to infer the presence of hundreds occurrences of chloride salts distributed throughout the southern highlands of Mars (Osterloo et al. 2008, 2010). We used NIR OMEGA data to characterize the surface composition of all putative chloride-bearing deposits and their surrounding terrains. Our systematic survey shows that none of the deposits is associated with signatures of sulfates. The deposits preferentially exhibit low albedo (<0.2) with weak pyroxene signatures. These signatures are best explained by the presence of mobile materials such as pyroxene-bearing dunes. A significant number of deposits is spectrally featureless with a medium albedo of 0.2-0.25. The spectral ratio technique applied to the deposits exhibiting pyroxene and blank signatures reveals a lack of absorptions and a blue slope in the 1-2.6 μm range, also reported by Murchie et al. (2009) and Glotch et al. (2011). For a few dozens of sites, we identified the presence of Fe/Mg-phyllosilicates in proximity to the chloride deposits, with some juxtaposed or even superimposed. We classified the chloride/phyllosilicates association in two groups. 1) Phyllosilicates exposed in small eroded terrains with distinct thermophysical properties from the surrounding terrain materials. These deposits are representative of the phyllosilicate-bearing outcrops that are commonly found in the ancient (pre-)Noachian plains and show no relationship with the chloride terrains. 2) Of special interest are the juxtaposed/superimposed phyllosilicates/chlorides deposits found exclusively in the intercrater plains of the northwestern Terra Sirenum region. In these rare occurrences, the phyllosilicate signatures correspond to a high standing rugged material overlying an anhydrous basement; this setting is rather unique and distinct from the common setting of phyllosilicates-bearing exposures of the ancient crust and those of extensive phyllosilicates-rich regions such as Mawrth Vallis and Nili Fossae. The spectral signatures are consistent with Fe/Mg smectites, with vermiculite and smectite-chlorite mixed-layer clays providing the best matches. The chlorides as mapped by THEMIS correspond to relatively thin and light-toned deposits spatially contiguous with the phyllosilicates. This close geographic relationship between the chlorides and the phyllosilicates suggests a genetic relationship between the two episodes of mineralization in this region. Terra Sirenum has been recently recognized as a complex ancient hydrological system (with groundwater upwelling and evaporation as the most likely scenario) from the concentration of diverse aqueous deposits (Wray et al. 2011; Glotch et al. 2011). The presence of these unique phyllosilicates/chlorides assemblages in the intercrater area of this region could therefore represent one of the episodes of water activity that affected the entire region. The origin of other chloride-bearing deposits widely distributed across the surface of Mars, however, remains puzzling.

Affiliated with

Also associated with

No associations

Rating

Compositional study of the putative chloride-bearing materials with OMEGA/MEx data and implications on their relationship with phyllosilicates does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Compositional study of the putative chloride-bearing materials with OMEGA/MEx data and implications on their relationship with phyllosilicates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compositional study of the putative chloride-bearing materials with OMEGA/MEx data and implications on their relationship with phyllosilicates will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-869529