Daniel C. Berman J. Alexis Palermo Rodriguez Catherine M. Weitz David A. Crown 20230107 vector digital data SIM 3492 Menlo Park, CA US Geologic Survey https://doi.org/10.3133/sim3492 Xanthe Terra is a high-standing cratered plain located southeast of Lunae Planum and south of Chryse Planitia in the western equatorial region of Mars. It contains landforms shaped by diverse geologic processes, including various scales of channels and valleys, chaotic terrains, delta fan deposits, and landslides. An extensive outflow channel system is located within Xanthe Terra, including Shalbatana and Ravi Valles, thought to have formed by catastrophic flooding during the Hesperian to Amazonian Periods. The study region within Xanthe Terra is defined by Mars Transverse Mercator (MTM) 00042 and 00047 quadrangles (lat 2.5° to −2.5° N., long 310° to 320° E.) and includes Orson Welles crater (124.5 km diameter, the source region for Shalbatana Vallis), the southernmost portion of Shalbatana Vallis, Aromatum Chaos (the source region for Ravi Vallis), the westernmost portion of Ravi Vallis, and the source area of Nanedi Valles. The Mars Odyssey Thermal Emission Image System (THEMIS) infrared (IR) daytime mosaic (100 m/pixel) was used as the primary base map. We constructed the geologic map of the source region of Shalbatana Vallis at 1:750,000 scale. We defined 16 geologic units in the map area, which we divided into the following groups: plains units, channel units, crater units, chaos units, flow units, and surficial units. Mapped linear features include ridge crests, scarp crests, channels, crests of crater rims, crests of buried or degraded crater rims, graben traces, grooves, troughs, and faults. Surface features include secondary crater chains and dark ejecta material. The geologic history of the map region can be summarized as follows: During the Noachian Period, ancient highland materials in the Xanthe Terra region, including lava and any ancient sedimentary units present, were reworked by impacts during the heavy bombardment, in particular the impact that formed the Chryse Planitia, and later underwent widespread resurfacing, likely as a combination of lava flows, reworked crater materials, and sedimentary deposits resulting in flat-lying, smooth plains. The Hesperian Period was characterized by the impact that formed Orson Welles crater and the subsequent formation of Shalbatana Vallis, as well as Aromatum Chaos and Ravi Vallis. During this period, depressions were filled with smooth material that was subsequently modified by collapse, subsidence, and flooding. Water filled and overflowed the tops of Orson Welles crater and other depressions. The Amazonian Period was characterized by ongoing collapse, as well as the formation of flow and surficial materials, including a lava flow that extends from Aromatum Chaos. 1:750,000-scale geologic map of the source region of Shalbatana Vallis, Mars. 19000101 publication date Complete None planned -50.0000 -40.0000 2.6000 -2.6000 None Mars Geology Planetary Science Xanthe Terra Orson Welles Crater Shalbatana Vallis None GIS software is required to view these data. Daniel C. Berman Planetary Science Institute mailing address

1700 East Fort Lowell, Suite 106

Tucson AZ 85179 US 520-622-6300 bermandc@psi.edu This map was prepared by the U.S. Geological Survey on behalf of the National Aeronautical Space Agency. Version 6.2 (Build 9200) ; Esri ArcGIS 10.7.1.11595 All features contain the field ‘type’, which corresponds to the originally mapped feature or unit. All attributes have been reviewed for accuracy. All feature classes in the final GIS have undergone a topology test and review for accuracy with the original georeferenced map. All data have been reviewed and verified for completeness. None Unknown Vector GT-polygon composed of chains 1 Xanthe Terra (MTM clon -30E) 1.0 -30.0 0.0 0.0 0.0 coordinate pair 0.0001 0.0001 meters D Mars 2000 Sphere Mars 2000 Sphere IAU IAG 3396190.0 1.0E-10 James A Skinner U.S. Geological Survey, Southwest Region Research Geologist mailing address

2255 North Gemini Drive

Flagstaff AZ 86001 US 928-556-7043 928-556-7014 jskinner@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.3133/sim3492 None 20200413 USGS Astrogeology Science Center Marc Hunter IT Specialist (Applications Software) mailing and physical

2255 N. Gemini Dr

Flagstaff AZ 86001 US 9285567133 mahunter@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 local time