Analog Sites for Missions II (2013) 4034.pdf

SULFATE-RICH PLAYA DEPOSITS FROM WHITE SANDS NATIONAL MONUMENT, A TERRESTRIAL ANALOG TO MARTIAN PLAYAS. M. Glamoclija1, A. Steele1, M. L. Fogel2 and V. Starke1, 1Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd NW, Washington, DC 20015, [email protected]; 2School of Natural Sciences, University of California, Merced.

Introduction: Sulfate-rich sedimentary formations tionary process provided the most significant contribu- have been identified as a widespread component of tion of sediment supply for the nearby dune field. At -exposed sequences. They are particu- the western margin of Alkali Flat, the lacustrine Otero larly interesting as they emphasize the importance of sediments consist of clays, carbonates and evaporites surface and near-surface aqueous processes during the indicating deposition in a semi-permanent saline lake planet’s history. Furthermore, playa/playa lake systems [6, 7], whereas the siliciclastic mud, corresponds to have received particular attention as the presence of fresh water deposits with fossilized plants and mol- /early sulfate-rich deposits have lusks [6]. The White sands playa sequences are offer- been identified by the Mars Exploration Rover Oppor- ing the present day playa deposits (found in the - tunity at [1, 2] and by Mars Recon- ern part of the monument) and lacustrine sequences naissance Orbiter (MRO) in sedimentary sequences transitioning to saline lake and playas covering the within crater, the Mars Science Laboratory span of the last 12,000 yrs. This is a unique environ- (MSL) landing site [3, 4]. We are proposing playa ment to study deposits similar to lithological sequences systems from the White Sands National Monument identified at Meridiani planum and Gale Crater to learn (WSNM) in New Mexico as an excellent model system more about their history, habitability and their poten- to study sulfate-rich evaporitic sequences that could tial for biosignatures preservation. help better understanding environmental parameters of Logistics and Environmental Constraints: White playa formation, climate reconstruction and explora- Sands playas are located within the monument area tion of biosignatures and habitability parameters for that is shared with the Holman Air Force Base. This inferred playa deposits on Mars. part of the monument is not open to tourists, therefore Mission Description: Multiple missions to Mars having low probability of anthropogenic contami- have identified sedimentary sulfates and sulfates are nation within the sampling area. The White Sands area one of the priority targets of the current MSL mission has typical Southwestern desert climate, which should to Gale Crater. The orbiting missions have detected be taken into consideration when planning the field- sulfate-rich deposits at different latitudes across the work. By being part of the national monument, this site Martian surface indicating the importance of this kind has great advantage of the park infrastructure, which of sedimentary formations. Understanding the deposi- includes park rangers who can help during the sam- tional history of these formations will provide a sig- pling, a few utility transportation vehicles, office space nificant insight into Martian geological history and and lab storage, camping grounds and accommodation potential habitability; which is also one of the major for researchers. Additionally, the site benefits from MSL goals and potentially interest of the future mis- being near town of Alamogordo, which can provide sions to Mars. additional infrastructure support and connection with Scientific Merit: The geological history of the pla- “the rest of the world”. yas at White Sands includes sedimentary sequences References: [1] Grotzinger J.P. et al. (2005) Earth that are very similar to those identified on Mars. The Planet. Sci. Lett. 240, 11-72. [2] Andrews-Hanna J.C. lacustrine sediments of pluvial Pleistocene Lake Otero et al. (2010) JGR, doi:10.1029/JE003485 [3] Milliken include facies composed mainly of siliciclastic and R.E. et al (2010) GRL, doi:10.1029/2009GL041870 carbonate mud, which are found together with underly- [4] Thomson B.J. (2011) Icarus, 214, 413-432. ing/surrounding sulfate and carbonate deposits, sug- [5] Fryberger S.G. (2000) gesting episodes of enhanced precipitation and contri- http://www.nps.gov/whsa/Geology%20of%20White% bution of relatively fresh water into an otherwise saline 20Sands/GeoHome.html. [6] Allen B.D. et al. (2009) lake during its high-stand [5, 6]. About 9,000 to 12,000 New Mexico Geol, 31, 19-25. [7] Langford R.P. (2003) yrs ago, the onset of significant regional aridity caused Quaternar. Intl. 104, 31-39. [8] Langford R.P. (2002) evaporation and deflation of Lake Otero [7]. Most of Proc. ICAR5/GCTE-SEN Conf., 400. the fresh water strata were removed by the initial onset Acknowledgements: Our research is supported by of aridity. The subsequent erosion and continuing arid- CIW NAI, ASTEP NNX12AP776. We are particularly ity through the Holocene created several erosional es- grateful to D. Bustos and K. Wirtz from NPS WSNM carpments into playa lake deposits [7, 8]. This defla- for their precious help during the field season.