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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 113, E05002, doi:10.1029/2007JE002981, 2008

Computer simulation of the role of groundwater seepage in forming Martian valley networks

Wei Luo

Department of Geography, Northern Illinois University, DeKalb, Illinois, USA


Alan D. Howard

Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia, USA


Abstract

The role of groundwater in forming Martian valley networks is simulated in a computer model as seepage erosion by contributing to surface runoff and as seepage weathering by causing accelerated weathering of bedrock, which makes its subsequent erosion and removal easier. Simulation results show that seepage erosion cannot mobilize large grain size sediment and is marginally effective at generating integrated valley networks with realistic rates of aquifer recharge. On the other hand, seepage weathering may play a major role in forming Martian valley networks. Seepage weathering combined with fluvial runoff creates stubby deep canyons with abrupt headwalls that are similar in morphology to terrestrial and Martian valley systems attributed to erosion by groundwater. Depending on the relative contribution of groundwater weathering to surface runoff erosion, a continuum of valley network morphology can be generated. Eolian modification masks the original differences in fluvial landforms, making different scenarios visually more similar. Martian valley networks may have developed through a range of combinations of runoff erosion and seepage weathering, which can complicate the interpretation of the processes based on final landform morphology. Unequivocal identification of seepage involvement of valley incision on Mars may not be possible without knowledge of subsurface properties (hydraulic conductivity, layering, degree of cementation, etc.) and the grain sizes of sediment transported through the valley systems.

Received 7 August 2007; accepted 20 February 2008; published 10 May 2008.

Keywords: seepage weathering; groundwater sapping; computer simulation; Martian valley networks; geomorphology; paleoclimate.

Index Terms: 5415 Planetary Sciences: Solid Surface Planets: Erosion and weathering; 5419 Planetary Sciences: Solid Surface Planets: Hydrology and fluvial processes; 1830 Hydrology: Groundwater/surface water interaction; 1847 Hydrology: Modeling; 1807 Hydrology: Climate impacts.

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 928910 bytes)

Citation: Luo, W., and A. D. Howard (2008), Computer simulation of the role of groundwater seepage in forming Martian valley networks, J. Geophys. Res., 113, E05002, doi:10.1029/2007JE002981.