A Model of Outflow Generation by Hydrothermal Underpressure Drainage in Volcano–Tectonic Environment, Shalbatana Vallis (Mars)
✍ Scribed by Nathalie A. Cabrol; Edmond A. Grin; Gilles Dawidowicz
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 801 KB
- Volume
- 125
- Category
- Article
- ISSN
- 0019-1035
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✦ Synopsis
high-pressure hydrothermal water circulation in a deeply fractured groundwater reservoir. Our model also explains
The survey of the Shalbatana Vallis course and the analysis of the distribution of the concentric peripheral and radial sys-the generation of outflow channels that use narrow grabens tems of faults east of Tharsis allow us to propose a model that as conduits. The tectonic stresses of the Tharsis swell led demonstrates the effect of volcano-tectonic strains generating to the formation of wrinkle ridges and narrow grabens as crossing fault systems where heat points allowed hydrothermal described by Sharp and Malin (1975), Tanaka and Golomdrainage of confined aquifers and generated headwater systems. bek (1989), Davis et al. (1991), Tanaka et al. (1991). Tecton-This model is qualitatively consistent with the strain of the ism (Carr 1974) and volcano-ground ice interactions spherical buldge of Tharsis expressed by extensional faults in-(Squyres et al. 1987) have already been advocated as a tersected by radial faults in the upper lithosphere. The southpossible origin for valley systems (Gulick and Baker 1990, ward course of the channel is oriented parallel to extensional Baker et al. 1991) and probably play a significant role in faults that are related to the wrinkle ridge field of Lunae Plathe generation of Shalbatana Vallis as will be demonstrated num. The channel is perpendicular to the normal radial faults of eastern Tharsis between the equator and ؊20؇ lat. The interin the following sections. section of these two fault systems generated weak points where The course of Shalbatana Vallis extends over a 1000 km magmatic material originating from the lithosphere entered the from Ganges Chasma (Carr 1995) down to Chryse Planitia upper crust through the self-sealing ice-saturated cryosphere. and crosses the Xanthe Terra province in Oxia Palus sub-We demonstrate that the system of fault intersections can exquadrangle. The upstream segment extends 800 km northplain: (a) the hydrothermal drainage of underground aquifers ward and is oriented parallel to the overall concentric ridge by convective heat flux and dike intrusion that formed chaotic formations of Lunae Planum. The wrinkle ridge field of terrains where source areas were generated beneath the cry-Lunae Planum is located 1800 km east of the stress field osphere and (b) the linear course of the sharp-rimmed, Uof Tharsis swell. Wrinkle ridges are interpreted as compresshaped Shalbatana Vallis intersected by successive chaos developments as governed by the underlying peripheral fault system. sional folding (Golombek et al. 1991), and other structural The physics of thermal underpressure vapor diffusion and the features produced by compressional strain such as dikes condensation into water is described as the exchange of heat are associated with deep extensional stresses and narrow between the magmatic intrusion and the ice-rich confined layers grabens (Tanaka and Golombek 1989). Concentric wrinkle beneath the chaotic terrains. © 1997 Academic Press ridges are better developed east of the rise (Watters and Maxwell 1983) and are interpreted as the result of horizontal radial compressions intervening at least up to 3500