269-10 Hybrid Geologic Map of the Mars South Polar Residual Cap: A Test Case for Integrating Compositional Data in Planetary Geologic Mapping

Session: Planetary Geologic Mapping Across the Solar System (Posters)

Presenting Author:

Authors:

Abstract:

The South Polar Residual Cap (SPRC) is a perennial deposit of surface ice near Mars’s south pole that covers an area of ~40,000 km². CO₂ ice comprises the brightest 1–10 m-thick exposures of the SPRC, which are divided by a series of lower-albedo scarps that expose dusty H₂O ice stratigraphy of the underlying South Polar Layered Deposits (SPLD). Nearly pure H₂O ice in the SPRC is exposed around the periphery of the CO₂ ice deposits, within a variety of SPRC/SPLD erosional features, and in an extensive outlying deposit north of McMurdo crater. 

The SPRC and SPLD have long been a focus of orbital observation due to their likely preservation of martian climate evolution at different timescales (~100 years vs. 10s of millions of years, respectively). Additionally, radar sounding has revealed subsurface CO₂ ice deposits beneath parts of the SPRC that have been linked to a 510,000-year record of orbital forcing, indicating that this intermediate time scale is also critical for understanding SPRC history. Given the complexity and variety of potential climate records in the region, it is critical that a new geologic framework be developed that can fully describe the nature of volatile-rich deposits in and around the SPRC, map their expression on the surface, and relate their stratigraphy to a history of deposition and modification.

Geologic mapping typically forms the foundation of such a framework. However, traditional planetary geologic mapping methods based on single-band, visible-wavelength data do not account for compositional information from increasingly common multi- and hyper-spectral imagers. This gap in methodology is a significant issue when mapping places like the SPRC where the composition of ice-rich materials has proven to be a key characteristic needed to properly identify units and interpret their histories. Therefore, to compile a new geologic framework for the SPRC region, we have generated a hybrid morphologic and compositional map that fully integrates this essential perspective on the geology of south polar climate records. We have cross-referenced the map and 2D radar profiles to generate interpretive cross sections and a geologic history of the region. The map serves as a test case for hybrid mapping in ice-rich terrains, which can inform future mapping efforts on Europa and beyond. 

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

doi: 10.1130/abs/2025AM-10255

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