Tectónica de piel fina en el Domo de Tharsis, Marte: pruebas de una neotectónica marciana

A photogeological reconnaissance of Viking mosaics and images of the Tharsis dome, Mars, has been carried out. Fourteen new areas of transcurrent faulting have been located which, together with other structures previously detected, permit to support a model in which the Thaumasia Plateau, the southeastern part of the Tharsis dome, is proposed to be an independent lithospheric block that experienced buckling and thrust faulting in Late Noachian or Early Hesperian times as a result of an E-W-directed compression. Evidence is presented that this stress field, rather than the Tharsis uplift, was decisive in the inception of Valles Marineris, that we consider a transtensive, dextral accident. The buckling spacing permits moreover to tentatively reconstruct a Martian Hesperian lithosphere similar in thickness to the mean present terrestrial oceanic lithosphere, thus supporting the possibility of a restricted lithospheric mobility in that period. Tharsis lithosphere was again subjected to shear stresses in Amazonian times, a period in which important accidents, such as strike-slip faults, wrinkle ridges, and straight and sigmoidal graben were formed under a thin-skin tectonic regime. The possible causes of those stresses, and especially their relationships to a putative period of plate tectonics, are discussed

New evidence for a volcanically, tectonically, and climatically active Mars

Geological analysis of Mars imagery supports the hypothesis that the planet has been the site of recent (< 10 Ma) volcanic and tectonic processes and glacier flow, and makes most likely previous suggestions of continuing endogenic and exogenic activity. Tectonic structures which deform very slightly cratered (at MOC scales) surfaces of Tharsis Montes and surrounding regions seem to attest to active tectonism (both extensional and transcurrent) on Mars. Exogenic processes in this region, such as a glacial origin for the aureole deposits on the northwestern flanks of the Tharsis Montes shield volcanoes, are supported by new data. The very recent age of these structures could be the first direct confirmation that drastic changes in obliquity are modulating the martian climate, such that an increase in obliquity would result in equatorial glaciers taking the place of the receding polar ice caps. If this and other concurring research is extended and confirmed, the ‘alive Mars’ which would emerge would constitute a most appealing place for exobiology and comparative planetology

Tharsis dome, Mars: New evidence for Noachian-Hesperian tbick-skin and Amazonian thin-skin tectonics

A photogeoIogical reconnaissance of Viking mosaics and images ofthe Tharsis dome has been carried out. Fifteen new areas of transcurrent faulting have been located which, together with other structures previously detected, support a model in which the Thaumasia Plateau, the southeastem part of the Tharsis dome, is proposed to be an independent lithospheric block that experienced buckling and thrust faulting in Late N oachian or Early Hesperian times as a result of an E-W directed compression. Evidence is presented that this stress field, rather than the Tharsis uplift, was decisive in the inception of Valles Marineris, which we consider a transtensive, dextral accident. The buckling spacing permits us, moreover, to tentatively reconstruct a Martian Hesperian lithosphere similar in elastic thickness to the mean present terrestrial oceanic lithosphere, thus supporting the possibility of a restricted lithospheric mobility in that periodo Tharsis lithosphere was again subjected to shear stresses in Amazonian times, a period in which important accidents, such as strike-slip faults, wrinkle ridges, and straight and sigmoidal graben, were formed under a thin-skin tectonic regime, while the lithosphere as a: mechanical unit had become too thick and sttong to buckle. The possible causes of those stresses, and especially their relationships to a putative period of pIate tectonics, are discussed