Ancient Geodynamics and Global-Scale Hydrology on Mars
Roger J. Phillips,1
Maria T. Zuber,23
Sean C. Solomon,4
Matthew P. Golombek,5
Bruce M. Jakosky,6
W. Bruce Banerdt,5
David E. Smith,3
Rebecca M. E. Williams,1
Brian M. Hynek,1
Oded Aharonson,2
Steven A. Hauck
II1
Loading of the lithosphere of Mars by the Tharsis rise explains
much of the global shape and long-wavelength gravity field of the
planet, including a ring of negative gravity anomalies and a
topographic trough around Tharsis, as well as gravity anomaly and
topographic highs centered in Arabia Terra and extending northward toward Utopia. The Tharsis-induced trough and antipodal high were largely in place by the end of the Noachian Epoch and exerted control
on the location and orientation of valley networks. The release of
carbon dioxide and water accompanying the emplacement of ~3 × 108 cubic kilometers of Tharsis magmas may have sustained a
warmer climate than at present, enabling the formation of ancient
valley networks and fluvial landscape denudation in and adjacent to the large-scale trough.
1 McDonnell Center for the Space
Sciences and Department of Earth and Planetary Sciences, Washington
University, St. Louis, MO 63130, USA.
2 Department
of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute
of Technology, Cambridge, MA 02139, USA.
3 Earth
Sciences Directorate, NASA/Goddard Space Flight Center, Greenbelt, MD
20771, USA.
4 Department of Terrestrial Magnetism,
Carnegie Institution of Washington, Washington, DC 20015, USA.
5 Jet Propulsion Laboratory, California Institute of
Technology, Pasadena, CA 91109, USA.
6 Laboratory
for Atmospheric and Space Physics, University of Colorado, Boulder, CO
80309, USA.
