A global geomorphologic map of Saturn’s moon Titan

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Abstract

Titan has an active methane-based hydrologic cycle1 that has shaped a complex geologic landscape2, making its surface one of most geologically diverse in the Solar System. Despite the differences in materials, temperatures and gravity fields between Earth and Titan, many of their surface features are similar and can be interpreted as products of the same geologic processes3. However, Titan’s thick and hazy atmosphere has hindered the identification of its geologic features at visible wavelengths and the study of its surface composition4. Here we identify and map the major geological units on Titan’s surface using radar and infrared data from the Cassini orbiter spacecraft. Correlations between datasets enabled us to produce a global map even where datasets were incomplete. The spatial and superposition relations between major geological units reveals the likely temporal evolution of the landscape and provides insight into the interacting processes driving its evolution. We extract the relative dating of the various geological units by observing their spatial superposition in order to get information on the temporal evolution of the landscape. The dunes and lakes are relatively young, whereas the hummocky or mountainous terrains are the oldest on Titan. Our results also show that Titan’s surface is dominated by sedimentary or depositional processes with a clear latitudinal variation, with dunes at the equator, plains at mid-latitudes and labyrinth terrains and lakes at the poles.

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Fig. 1: SAR images showing examples of the main classes of geomorphologic units on Titan.
Fig. 2: Global map of Titan’s major geomorphological units.
Fig. 3: Example of the mapping method from regional to global.

Data availability

The Cassini data used in this paper are available from NASA’s Planetary Data System (PDS) (https://pds.nasa.gov). Data on map units are available from the corresponding author upon reasonable request.

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Acknowledgements

Part of this work was conducted at the Jet Propulsion Laboratory (JPL), California Institute of Technology (Caltech), under contract with NASA. This research was supported in part by the Cassini-Huygens mission, a cooperative endeavour of NASA, the European Space Agency and Agenzia Spaziale Italiana managed by JPL/Caltech under a contract with NASA. This research was supported in part by the NASA Astrobiology Institute through its JPL-led team entitled ‘Habitability of Hydrocarbon Worlds: Titan and Beyond’ and the Cassini Data Analysis Program (grant number NN13D466T to R.M.C.L.). D.A.W. was supported through a grant from NASA’s Outer Planets Research Program (grant number NNX14AT29G). A.L.G. was supported by the Institut Universitaire de France.

Author information

R.M.C.L. led the work and wrote the paper. M.J.M., A.M.S., T.V. and M.F. carried out the mapping. A.S. carried out the VIMS analysis and advised on the writing up of VIMS results. A.L.G. advised on interpretation and wrote part of the radiometry results. A.G.H. and S.P.D.B. provided the projected data for the mapping and advised on interpretation. J.R. and S.D.W. advised on interpretation of radar units. E.P.T. advised on the interpretation of ISS data. The Cassini RADAR team acquired and processed the data.

Correspondence to R. M. C. Lopes.

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Peer review information Nature Astronomy thanks Jason Soderblom and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Lopes, R.M.C., Malaska, M.J., Schoenfeld, A.M. et al. A global geomorphologic map of Saturn’s moon Titan. Nat Astron (2019) doi:10.1038/s41550-019-0917-6

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