GEOLOGIC MAPPING OF MTM QUADRANGLES -20022, -25022, -20017, AND -25017 IN MARGARITIFER TERRA ON MARS

The Margaritifer Terra and northwestern Noachis Terra regions on Mars record a long history of aqueous processes including the highest density of valley networks on the planet, the Uzboi-Ladon-Morava outflow system, and younger alluvial fans within numerous craters. We are creating a United States Geological Survey (USGS) Scientific Investigation Map (SIM) at 1:1,000,000 scale of Mars Transverse Mercator (MTM) quadrangles -20022, -25022, -20017, and -25017 in Margaritifer Terra along the boundary of northwestern Noachis Terra (17.5°S to 27.5°S between 335°E and 345°E). Our map encompasses the medial to distal portions of the Samara-Himera and Paraná-Loire valley network systems, two of the largest and best integrated valley systems on Mars, whose trunk valleys integrate much of the drainage coming from surrounding areas. Relatively pristine segments of medial-to-distal Samara Valles are observed to originate west of Jones crater and are consistent with late drainage and ponding on the Jones ejecta related to water from impact-melted ice (see GSA 2023 Abstract ID# 394128 and 393213). Major units within the map include severely deformed units (chaos), basin fill, crater fill, vallis, fan, plateau, craters, and highlands (that may include an originally extensive, but considerably eroded mantling unit). Linear features include fluvial channels, wrinkle ridges, the Ladon basin impact ring structures, and crests of crater rims.

Prior geologic mapping in this greater region focuses on the drainage evolution and juxtaposition of various units in either the eastern or western portions of Margaritifer Terra and adjacent northwestern Noachis Terra. Mapping MTM quadrangles -20022, -25022, -20017, and -25017 will fill the gap between these existing USGS maps to yield a complete regional view, thereby enabling regional evaluation of valleys associated with aqueous processes. The final product will provide the scientific community with a dataset to understand the morphologic and morphometric investigations of valleys and fluvial/alluvial deposits, the timing of fluvial activity for climate models, and may inform efforts related to understanding the history of Martian habitability.