Evidence of Titan's Climate History from Evaporite Distribution

TL;DR

This study maps the global distribution of evaporite-like material on Titan, revealing insights into its past climate and liquid history through spectral analysis and geomorphological correlations.

Contribution

It provides the first global distribution map of 5-micron-bright evaporite candidates on Titan, linking them to past liquid presence and climate conditions.

Findings

5% of Titan's surface covered by 5-micron-bright material

Concentrations in equatorial basins Tui and Hotei Regio

Implications for Titan's past liquid activity and climate

Abstract

Water-ice-poor, 5-$\mu$m-bright material on Saturn's moon Titan has previously been geomorphologically identified as evaporitic. Here we present a global distribution of the occurrences of the 5-$\mu$m-bright spectral unit, identified with Cassini's Visual Infrared Mapping Spectrometer (VIMS) and examined with RADAR when possible. We explore the possibility that each of these occurrences are evaporite deposits. The 5-$\mu$m-bright material covers 1\% of Titan's surface and is not limited to the poles (the only regions with extensive, long-lived surface liquid). We find the greatest areal concentration to be in the equatorial basins Tui Regio and Hotei Regio. Our interpretations, based on the correlation between 5-$\mu$m-bright material and lakebeds, imply that there was enough liquid present at some time to create the observed 5-$\mu$m-bright material. We address the climate implications surrounding a lack of evaporitic material at the south polar basins: if the south pole basins were filled at some point in the past, then where is the evaporite?