Valley formation in Margaritifer Sinus, Mars, by precipitation-recharged ground-water sapping
- 1Department of Earth Sciences, State University of New York, College at Buffalo, Buffalo, New York 14222, USA
Abstract
Drainage morphometry and geologic mapping place new constraints on valley origin in Margaritifer Sinus, Mars. Preserved valleys are constant width, typically head near divides, possess fourth-order trunk segments, and were formed from late Noachian into earliest Hesperian time. Relative to terrestrial systems, the Martian valleys have low densities (<0.1 km/km2), relief ratios (0.001–0.13), and ruggedness numbers (0.005–0.086), and the sediment volume in associated sinks exceeds the volume excavated by upstream segments. Valley characteristics are consistent with formation by precipitation-recharged ground-water sapping within a layered, permeable substrate.
Footnotes
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↵GSA Data Repository item 200025, A characterization of Martian valley width, is available on request from Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301-9140, editinggeosociety.org, or at www.geosociety.org/pubs/drpint.htm.
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↵*Present Address: NASA Headquarters, Code SR, Washington, D.C. 20546, USA
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Data Repository item 200025 contains additional material related to this article.
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- Accepted December 20, 1999.
- Received June 21, 1999.
- Revision received December 7, 1999.
- Geological Society of America
