142-1 Geologic Mapping of the Jones Crater Region on Mars: Reconstructing a History of Fluvial, Impact, and Erosional Processes

Session: Geomorphology and Landscape Evolution of Mars (Posters)

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Abstract:

Our United States Geological Survey (USGS) Scientific Investigation Map (SIM) encompasses Jones crater and the medial to distal portions of the Samara-Himera and Paraná-Loire valley systems. The 1:1,000,000 scale map covers four Mars Transverse Mercator (MTM) quadrangles, -20022, -25022, -20017, and -25017 (from 17.5°S to 27.5°S between 335°E and 345°E). The primary objectives of this mapping effort are to constrain the relative timing, duration, and importance of aqueous processes in relation to other geologic processes, and to integrate these four quadrangles with previously published USGS maps to the east, west, and north. The regional framework provides a comprehensive view of the landscape that supports morphologic and morphometric studies of valleys and fluvial/alluvial deposits, while improving constraints on the timing of fluvial activity and its implications for the climate history of Mars.

The map includes a variety of geologic units, including craters, central peaks, crater floors, fan-shaped deposits, valleys, channels, and the widespread terra unit. Mapped linear features include fluvial channels, wrinkle ridges, Ladon basin impact ring structures, crater rims, grabens, scarps, and troughs. Within the map, the Samara-Himera and Paraná-Loire valley systems are generally degraded, except where segments adjacent to the Jones crater ejecta were reactivated by drainage associated with ice that melted following the Late Hesperian impact. The Noachian to Hesperian aged terra unit, mapped broadly in adjacent quadrangles, forms a widespread, variably dissected surface between degraded impact craters and is interpreted to be formed and modified through multiple processes, including impact cratering, ejecta emplacement, prolonged weathering, and erosion primarily by water and wind. In our map area, the terra unit is mantled, exhibits a dark signature in THEMIS daytime infrared data, and has variable albedo in CTX data. Unlike the terra unit in adjacent quadrangles, the surface here commonly exhibits a stippled texture on the plains and is locally stripped over length scales of 500m to 1 km. This stripping is most prevalent within valleys and along the interior walls of craters.

This regional geologic map highlights the timing and interaction of fluvial, impact, and erosional processes, advancing our understanding of the long and complex evolution of the Margaritifer Terra region.

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