The south polar layered deposits (spld) of mars are composed of perennial water ICE and dust that surround the CO2-dominated residual ICE cap (sric). The spld, much like the north polar layered…

The University of Colorado at Boulder received a $600,719 research grant from a civilian federal agency to produce a United States Geological Survey (USGS) Science Investigation Map of Mars's South Polar Region (70°S to 90°S) at a map scale of 1:2,000,000. The contract, awarded on April 14, 2021, with completion targeted for April 13, 2027, requires the university to synthesize data from multiple orbital instruments including the THEMIS Daytime Infrared Mosaic (100 m/pixel primary basemap), Mars Context Camera (CTX), and Mars Orbiter Laser Altimeter (MOLA) to create a comprehensive geologic map. This mapping effort addresses a critical knowledge gap, as no high-resolution, low-map-scale geologic map of the South Polar Region currently exists, despite its scientific importance.

The geologic map will provide essential context for interpreting the South Polar Layered Deposits (SPLD)—a composition of perennial water ice and dust surrounding Mars's CO2-dominated residual ice cap. Understanding the SPLD is crucial for decoding Mars's climate history, particularly the deposit's complex erosional history and its record of ancient climate variations. Unlike the better-studied North Polar Layered Deposits, the SPLD exhibits significantly older surface ages (potentially tens of millions of years) and higher dust content, making it enigmatic yet vital for understanding the Amazonian water ice mass balance and broader Martian climate evolution. No set-aside was used for this contract award.

The south polar layered deposits (spld) of mars are composed of perennial water ICE and dust that surround the CO2-dominated residual ICE cap (sric). The spld, much like the north polar layered deposits (npld), are thought to contain an obliquity-driven climate signal. However, unlike the npld, the spld surface age from numerous previous crater counting studies places the deposit at least orders of magnitude older than the npld surface, and perhaps 10S of myrs old (far exceeding the modeled ~5 MYR total lifetime of the npld). Low radar reflectivity zones (lrzs) under the sric are highly likely to be CO2 ICE deposited in previous ~100 KYR climate variations, while the compositions and depositional history of lrzs underlying the spld are still not well constrained. The composition and timing of these deposits are key for understanding how the spld accumulated. Additionally, the spld s potentially complex erosional history, indicated by its high bulk dust content compared to the npld, complicates unraveling what climate record could be contained within the deposit. These features make the spld enigmatic but crucial to understanding the amazonian water ICE mass balance of mars, and by extension martian climate history. A geologic map of the south polar region of mars would provide necessary context to serve as the foundation for these interpretations however, a high-resolution/low-map-scale geologic map is not currently available. The proposed work will produce a united states geological survey (USGS) science investigation map of the south polar region of mars (70 s to 90 s) at a final map scale of 1:2,000,000. We will use the themis daytime IR mosaic (100 m/pixel) as our primary basemap, with mars context camera (CTX) and mars orbiter laster altimeter (mola) as supplemental datasets.