First USGS Global Geologic Map of Titan

Geologic maps are important tools to understand the nature and timing of geologic processes that have shaped planetary surfaces, and are key to understanding their evolution over geologic time. We have been funded by NASA's Cassini Data Analysis program to produce a global geologic map of Saturn's moon Titan. This map will be published by the U.S. Geological Survey at a scale of 1:20,000,000. This map is based on a 1:800,000 scale unified quadrangle geologic map, produced in ArcGIS™ by Co-Is Malaska, Schoenfeld, Birch, Lopes and associates of the Cassini Science Team. PI Williams has worked with the Co-Is over the last decade to define the mapping methodology for Titan using Cassini Radar, ISS, and VIMS data. Our first 6-unit global geomorphological map was published in 2020 [1].

Over the last year Co-I Malaska has simplified our 43-unit, 1:800K map to make a visually compelling map publishable on a single USGS map sheet at 1:20M. The 43 units in the 1:800K map have been merged into 12 units covering Titan's 6 primary terrain types: plains, labyrinths, hummocky materials, dunes, craters, and (hydrocarbon) lakes. Our current unit list includes: Labyrinth (polygonal), Labyrinth (valleyed), Plains (bright), Plains (dark), Craters (three degradation states), Mountains/Hummocky Terrain, Dunes, Broad Filled Depressions (hydrocarbon seas), Lakes (filled), and Lakes (empty). Production of this map requires merging or deleting linear features ≤30 km and polygons ~<900 km2 as described in the Description of Map Units. Titan's hydrocarbon fluvial channels and lakes (both filled and empty, ~<900 km2) have been rendered as linear and point feature layers, respectively. This presentation presents the initial version of the map submitted to the USGS for peer review.

Reference: [1] Lopes, R.M.C., M.J. Malaska, A.M. Schoenfeld, A. Solomonidou, S.P.D. Birch, M. Florence, A.G. Hayes, D.A. Williams, J. Radebaugh, T. Verlander, E.P. Turtle, A. Le Gall, S. Wall, and the Cassini RADAR Team, 2020, A Global Geomorphologic Map of Saturn's Moon Titan, Nature Astronomy, 4, 228-233. https://doi.org/10.1038/s41550-019-0917-6.