P065-0010
RECONSTRUCTING THE FLUVIAL HISTORY OF ANTONIADI CRATER: EVIDENCE FOR NOACHIAN AND AMAZONIAN STREAM NETWORKS ON MARS

Tuesday, 15 December 2020
Poster
Abdallah Zaki1, Kenneth S Edgett2, Sanjeev Gupta3, Maurizio Pajola4, Joel Davis5, Cory M. Hughes6, Stephen Watkins1, Luis Valero1, Peter M Grindrod7, Nicolas Thomas8, Gabriele Cremonese9 and Sebastien Castelltort1, (1)University of Geneva, Department of Earth Sciences, Geneva, Switzerland, (2)Malin Space Science Systems, San Diego, CA, United States, (3)Imperial College London, Earth Science and Engineering, London, United Kingdom, (4)INAF-Astronomical Observatory of Padova, Padova, Italy, (5)Natural History Museum, Department of Earth Sciences, London, United Kingdom, (6)Western Washington University, Bellingham, WA, United States, (7)Natural History Museum, London, United Kingdom, (8)University of Bern, Physics Institute, Space Research and Planetary Sciences, Bern, Switzerland, (9)INAF - Astronomical Observatory of Padova, Padova, Italy
Abstract:
Hundreds of candidate paleolake sites have been recognized from orbiting and landing Mars missions. One of these potential paleolake sites is the 400-km diameter impact crater, Antoniadi. It might have hosted an open-basin lake fed by valley networks from the north and east showing a complexity of fluvial activity during the early climate of Mars. We use Context Camera (CTX), High-Resolution Imaging Science Experiment (HiRISE), Color and Stereo Surface Imaging System (CaSSIS), and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data to investigate landforms in Antoniadi that record a range of paleohydrological processes. Antoniadi exhibits diverse landforms suggesting fluvial erosion by surface and subsurface hydrology, including valley networks, fan-shaped sediment deposits, and short and stubby branched ridges that record a previous fluvial system. One of the fans consists of three lobes that aggraded at different elevations; these lobes might have formed as a response to water level changes. The modeled age of the valley networks and fan-shaped deposits suggest fluvial erosion and deposition at 3.7 ± 0.1 Ga. A deflated surface in the center of the crater yielded an age of 2.4 ± 0.1 Ga; this surface is superposed by the short, stubby drainage network (now expressed as ridges) that occur over a ~700 km2 area. These streams drained into a trunk (0.6-2-km-wide; 30-km-long) that debouched into a small depression. The morphology of these branches supports groundwater release as the primary driver of the second interval of the fluvial activity, as they originated near a set of faults that might have served as conduits that brought the water to the Martian surface. The modeled ages, coupled with morphological reconstruction, suggest fluvial erosion and deposition triggered by precipitation-fed runoff during the Noachian, followed by groundwater processes during early Amazonian. Once the fluvial processes declined, erosion inside Antoniadi was governed by aeolian processes to create paleo-stream ridges, yardangs, and various forms of dunes. We are engaged in further work on a mineralogical investigation to examine the diversity of the spectral signatures across different landforms, and what this can tell us about fluvial activity during the early Mars.
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