GSA Connects 2021 in Portland, Oregon

Paper No. 14-11
Presentation Time: 10:45 AM


WIENS, Roger1, COUSIN, Agnes2, OLLILA, Ann1, BEYSSAC, Olivier3, MAURICE, Sylvestre2, JOHNSON, Jeffrey4, MANGOLD, Nicolas5, CLEGG, Sam1, QUANTIN, Cathy6 and MANDON, Lucia7, (1)Space & Planetary Exploration Team, Los Alamos National Laboratory, Los Alamos, NM 87545, (2)Institut de Recherche en Astrophysique et Planétologie, 9 Avenue du Colonel Roche, Toulouse, 31400, France, (3)IMPMC, Universite Pierre et Marie Curie, Paris, 75005, France, (4)Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Road, MP3-E169, Laurel, MD 20723, (5)Laboratoire De Planétologie Et Géodynamique, U. Nantes, Nantes, 44322, France, (6)Universite de Lyon, Lyon, France, (7)Observatoire de Paris, Meudon, Meudon, France

The Perseverance rover landed in Jezero crater ~2 km from the delta front of Neretva Vallis and just E of a NE-SW strip of rugged terrain named Seitah. Initial images revealed relatively flat rocks as well as upright boulders, some of the latter strongly pitted at scales of ~1 mm to several cm. The first chemical and mineral spectra concur that rock surfaces are hydrated. VISIR and LIBS both show ferrihydrite compositions at some observation points, and LIBS observes some ilmenite compositions. Near-IR spectra also suggest some nontronite. Landing site elemental chemistry generally indicates pyroxene compositions and numerous points with glassy compositions variably depleted in Al and enriched in Si relative to feldspars. Starting around Sol 70, as the rover headed S and then SW, olivine became evident in both IR spectra and LIBS chemistry in 1-3 mm pebbles (though not in the rocks) with Mg #s ~70. Audio recordings of LIBS plasmas indicate relatively hard rock surfaces. Heterogeneity among multiple LIBS observations (~300 µm dia. FOV) on the same target suggests grain sizes are at least that large on average. Sparse SuperCam Raman spectra of exposed rock surfaces may show weak silica glass signatures; time-resolved fluorescence has been observed, likely from Fe3+ substituting in feldspars.

SuperCam’s imaging supports investigations of both local and distant rock textures. In local rocks, some vesicular and ropy textures may suggest igneous flows, and the texture of the Seitah region (Tarnas et al., Sun et al., this meeting) show a few protruding layered, likely sedimentary outcrops. Observations of delta remnant Kodiak (~1.4 km from the landing site) indicates classic Gilbert delta stratigraphy. Both Kodiak and the delta front have conglomeratic boulders in the upper portions (Gupta et al., this meeting). Other topographic highs, Santa Cruz (~2.5 km NE) and Pilot Pinnacle (< 1 km SW), are relatively featureless in images and VISIR spectra.

Acknowledgements: Thanks to all on the SuperCam and M2020 teams who contributed to this work, including V. Sautter, T. Bosak, S. Sharma, J. Madariaga, S. Le Mouelic, A. Brown, B. Chide, K. Benzerara, A. Udry, et al.