114-4 A New Global Database of Martian Valley Networks from Context Camera (CTX) Imagery

Session: Geomorphology and Surface Processes Across the Solar System (Poster)

Presenting Author:

Authors:

Abstract:

Branching valley networks are among the most compelling evidence for liquid surface water on early Mars. Existing maps, constructed from Viking, THEMIS, and MOLA data, are widely used to study Mars' climate, hydrology, tectonics, and geologic history, and have proven to be an incredibly useful resource for the scientific community. However, the low-resolution and incomplete data from which these previous catalogs were produced results in inherent uncertainty and limitations for the studies that utilize these data.

We are building the first global valley network database derived directly from CTX imagery. Using the global CTX mosaic of Dickson et al. (2023) as the primary basemap, we are mapping valleys manually at 1:250,000 scale. The mapping includes all incised valleys regardless of age or inferred formative process, with classification into geomorphic categories, including valley networks, lake overflows, outflow canyons, canyon-adjacent valleys, and valleys on volcanoes. We also differentiate between preserved valleys and inferred connections through low-relief terrain, which was not included in prior global datasets but is critical for hydrologic modeling.

Mapping in Terra Cimmeria, Noachis Terra, and Terra Sabaea yields valley densities approximately half those reported in previous datasets. This difference arises from the superior resolution of CTX imagery, which enables confident discrimination between true eroded valley systems and landforms that appear valley-like in lower-resolution THEMIS or MOLA data but are unrelated to valley incision.

We are compiling quantitative metrics for each valley segment and system, including length, drainage density, and classification. These metrics will allow users to test climate models, reconstruct water volumes required for erosion, establish temporal relationships with other geologic features, and assess the degree of hydrologic integration on early Mars. The final product will be archived with the NASA Planetary Data System Cartography and Imaging Sciences Node in both PDS-compliant GeoCSV and Esri Shapefile formats.

This database will provide the highest-resolution, most complete, and internally consistent global map of Martian valley networks to date. Potential applications include refining estimates of global water volumes (currently spanning orders of magnitude depending on the input dataset), testing precipitation vs. groundwater-sapping origins, and evaluating hypotheses about the presence of an ancient ocean. Given CTX's resolution and near-global coverage, we anticipate that this dataset will become the definitive reference for Martian valley distribution for decades.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10203

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