%0 Journal Article
%A Anguita, Francisco
%A Babín Vich, Rosa Blanca
%A Benito, Gerardo
%A Gómez Ortiz, David
%A Collado, Ana
%A Rice, James W.
%T Chasma Australe, Mars: Structural Frameworkfor a Catastrophic Outflow Origin
%D 2000
%@ 0019-1035
%U https://hdl.handle.net/20.500.14352/59059
%X Chasma Australe, 500 km long and up to 80 km wide, is the mostremarkable of the martian south pole erosional reentrants carved inthe polar layered deposits. We have interpreted Chasma Australeerosional and depositional features as evidence for a flood origin,which we have reconstructed using a modified Manning equation.The main characteristics of the flow are a water velocity between30 and 50 m s¡1 and discharge values between 7 x 10^8 and 3 x 10^9 m3 s-1, very near to MGS data-based estimations for martianoutflow channels (D. E. Smith et al. 1998, Science 279, 1686–1692).We thus postulate that Chasma Australe originated in a catastrophicflood.The tectonic study of an area (roughly 20 million km2 in size)around Mars’ south pole included the measurement and projectionin rose diagrams of more than 300 lineaments, of which 85 werewrinkle ridges and the rest straight scarps. The whole set of lineamentscan be explained by a stress field with a d1 N10ºE in strike,the wrinkle ridges being reverse faults and the other lineaments directand strike-slip faults. The straight layout of parts of ChasmaAustrale almost 200 km long suggests that the chasma was carvedfollowing a fracture network. The effectiveness of the erosional process(the canyon is up to 1000 m deep) leads us to suspect that thiscarving was preceded by a sapping period. Endogenetic and exogeneticprocesses would thus have contributed to the origin of thislandform
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