Wiseman, Sandra M. and Arvidson, R. E. and Morris, R. V. and Poulet, F. and Andrews-Hanna, J. C. and Bishop, J. L. and Murchie, S. L. and Seelos, F. P. and Des Marais, D. J. and Griffes, J. L. (2010) Spectral and stratigraphic mapping of hydrated sulfate and phyllosilicate-bearing deposits in northern Sinus Meridiani, Mars. Journal of Geophysical Research E, 115 . Art. No. E00D18 . ISSN 0148-0227 http://resolver.caltech.edu/CaltechAUTHORS:20100803-094404710
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We present detailed stratigraphic and spectral analyses that focus on a region in northern Sinus Meridiani located between 1°N to 5°N latitude and 3°W to 1°E longitude. Several stratigraphically distinct units are defined and mapped using morphologic expression, spectral properties, and superposition relationships. Previously unreported exposures of hydrated sulfates and Fe/Mg smectites are identified using MRO CRISM and MEX OMEGA near‐infrared (1.0 to 2.5 µm) spectral reflectance observations. Layered deposits with monohydrated and polyhydrated sulfate spectral signatures that occur in association with a northeast‐southwest trending valley are reexamined using highresolution CRISM, HiRISE, and CTX images. Layers that are spectrally dominated by monohydrated and polyhydrated sulfates are intercalated. The observed compositional layering implies that multiple wetting events, brine recharge, or fluctuations in evaporation rate occurred. We infer that these hydrated sulfate‐bearing layers were unconformably deposited following the extensive erosion of preexisting layered sedimentary rocks and may postdate the formation of the sulfate‐ and hematite‐bearing unit analyzed by the MER Opportunity rover. Therefore, at least two episodes of deposition separated by an unconformity occurred. Fe/Mg phyllosilicates are detected in units that predate the sulfateand hematite‐bearing unit. The presence of Fe/Mg smectite in older units indicates that the relatively low pH formation conditions inferred for the younger sulfate‐ and hematitebearing unit are not representative of the aqueous geochemical environment that prevailed during the formation and alteration of earlier materials. Sedimentary deposits indicative of a complex aqueous history that evolved over time are preserved in Sinus Meridiani, Mars.
|Additional Information:||© 2010 American Geophysical Union. Received 2 February 2009; revised 23 September 2009; accepted 22 December 2009; published 2 July 2010. The authors acknowledge financial support from the NASA Mars Reconnaissance Orbiter project and the NASA Graduate Student Research Program and thank the CRISM, OMEGA, CTX, and HiRISE operations teams for their efforts.|
|Subject Keywords:||CRISM; Meridiani; stratigraphy|
|Official Citation:||Wiseman, S. M., R. E. Arvidson, R. V. Morris, F. Poulet, J. C. Andrews-Hanna, J. L. Bishop, S. L. Murchie, F. P. Seelos, D. Des Marais, and J. L. Griffes (2010), Spectral and stratigraphic mapping of hydrated sulfate and phyllosilicate-bearing deposits in northern Sinus Meridiani, Mars, J. Geophys. Res., 115, E00D18, doi:10.1029/2009JE003354.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||03 Aug 2010 18:24|
|Last Modified:||26 Dec 2012 12:16|
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