Basilevsky, Alexander

Greeley, Ron

Hauber, Ernst

Head, James

Hoffmann, Harald

Ivanov, Boris

Jaumann, Ralf

McCord, Thomas

Neukum, Gerhard

Van Gasselt, Staphan

Werner, S.

Williams, D.A.

Wolf, Ursula

Institute of Transport Research:Publications

The Geological Evolution of Mars as Seen through theMars Express High Resolution Stereo Camera (HRSC)G. Neukum (1), A.T. Basilevsky (2), S. van Gasselt (1), R. Greeley (3), E. Hauber(4), J.W. Head (5), H. Hoffmann (4), B.A. Ivanov (6), R. Jaumann (4), T.B. McCord(7), S. Werner (1), D. A. Williams (3), U. Wolf (4), and the HRSC Co-I Team(1) Inst. of Geosciences, Freie Univ. Berlin, Germany; (2) Vernadsky Inst. of Geochemistry,Russia; (3) Arizona State U., USA; (4) Inst. of Planetary Research, DLR, Germany; (5) BrownU., Providence, USA; (6) Inst. of Dynamics of Geospheres, Russia; (7) Space Science Inst.,Winthrop, USAAfter two years of orbital acquisition of high-res. stereo and color data by the HRSCexperiment on the ESA Mars Express Mission and nearly 30% coverage of the mar-tian surface at a resolution of better than 20m/pixel, we are beginning to understandthe geological evolution of Mars at different scales (globally, regionally, and locally)considerably better. The combination of the new HRSC data with MOC data wherehigh-res context information can be merged with detailed local information, and thecombination with color data giving the distribution of different materials as well asstereo viewing capability open up a new domain of photogeological high-precision in-terpretation. We can demonstrate that there has been episodic volcanic, hydrothermal,fluvial, and glacial activity throughout the whole history of Mars though declining inmagnitude through time and peaking at certain periods in the past, becoming confinedmore and more to certain regions or locales, such as the poles, the highland-lowlandboundary and in particular the Tharsis and Elysium regions and vicinities. What isbecoming much clearer now is that in parallel to the cessation of the martian highlandvolcanism ˜3.5 Ga ago and probably the rapid loss of the martian atmosphere withina few 100 Ma by that time, Mars fell dry on a global scale. It is now very clear onthe basis of our analysis of HRSC data the early “wet and warm” Mars as put for-ward after Viking, is more of a fiction than reality. Whether a global large ocean inthe north ever existed is less clear than ever, the odds seem to be against it. At least by3.5 Ga ago, probably already around 3.8 Ga ago, our data tell us, it was gone if it wasthere before and Mars fell dry rapidly on a global scale. Nevertheless, from time totime through the Aeons until today Mars has been volcanically active in periods, andlargely through this activity water seems to have been released from ice-rich layers onthe surface or sub-surface or from aquifers which formed fresh small-channel systemslocally and triggered glacial processes through the freezing water. The most outstand-ing recent finding is that the ages of activity periods derived from the analysis of theimaging data in terms of superimposed crater frequencies coincide with age groups ofmartian meteorites whose ages have been determined by isotope measurements in thelab.1

The Geological Evolution of Mars as Seen through the Mars Express High Resolution Stereo Camera (HRSC)

The Geological Evolution of Mars as Seen through the Mars Express High Resolution Stereo Camera (HRSC)

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