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Geologic Map and Ice Degradation of Martian S1094b Fresh Crater

Presentation #300.03 in the session Martian Ice, Climate, and Habitability (Oral Presentation)

Published onOct 23, 2023
Geologic Map and Ice Degradation of Martian S1094b Fresh Crater

On December 21, 2021, a new crater named S1094b formed in northern Amazonis Planitia, Mars [1]. It has been localized through the contemporary exploitation of InSight seismic data [2,3] and MRO HiRISE images [4]. The impact occurred over an almost-flat region characterized by volcanic units [5]. The lack of up-range ejecta indicates an oblique impact (~30°) coming from SW [1,6,7]. The crater has a diameter of ~150m, a depth of ~21m, and shows a slightly irregular rim shape and a hummocky floor. The interesting feature of this fresh crater is the exposure of water ice patches among its proximal ejecta, which have never been observed at such low latitudes [1].

We mainly used Mars Orbiter Laser Altimeter [8], HiRISE RGB images, and Digital Terrain Model to identify different morphological units present in the area. The mapping process has been made through Qgis software and well-established methods [9-10].

S1094b crater shows many surface characteristics that we separated into 6 different units, 3 landforms and 3 linear features. The local geology presents a darker unit excavated by secondary craters resulting from S1094b, which we interpreted as a volcanic unit richer in mafic minerals [11] underlying the brighter one or alternatively, as a less-altered portion of the same volcanic unit excavated from underneath the more altered one.

We also mapped ~4500 boulders and ~3880 freshly-ejected icy boulders, deriving their size-frequency distribution (SFD). We then compared the cumulative number of icy boulders with the one obtained from a ~1 year later HiRISE image, revealing a decrease of around 2500. We are currently investigating the ice degradation process coupling thermal modelling approaches with boulder SFD calculated at different times. These results will be presented at the time of the conference.

Acknowledgements: This study has been supported by the Italian Space Agency (ASI-INAF agreement no. 2020-17-HH.0)

References: [1] Posiolova, L. et al., 2022 Science, 378, 412. [2] Garcia, R. F. et al., 2022 Nat. Geo., 15(10), 774. [3] Tanaka, K. L., et al., 2005 US Department of the Interior, USGS. [4] McEwen, A. S., et al., 2007. JGR, 112. [5] Tanaka, K.L. et al., 2014 USGS Scientific Investigations Map 3292, pamphlet 43 [6] Gault, D. E., et al., 1978. New York, Pergamon Press, Vol. 9 p. 3843. [7] Kenkmann, T. et al., 2014 Journal of Structural Geology, vol 62, p. 156. [8] Smith, D. E. et al., 2001. JGR, 106, 23689. [9] Galluzzi, V., L. et al., 2016. Journal of Maps 12 (sup1): 227–38. [10] Skinner, J. A., et al., 2018 USGS. [11] Stockstill‐Cahill, K. R. et al., 2008. Journal of Geophysical Research: Planets, 113(E7).

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