GEOLOGIC RECORD OF AN ANCIENT MOBILE MARTIAN LITHOSPHERE

Prior to the Hellas impact, estimated to have occurred around 4.0 Ga, Mars had a powerful dynamo/magnetosphere and an interaction among the landmass, ocean, and atmosphere through hydrological cycling driven by the Sun, known as Habitable-Trinity planetary conditions [1]. In addition, a mobile lithosphere appears to have been in operation during this time. A prime sign of this is a systematic, spatial arrangement of landforms of the Thaumasia Plateau and surroundings of Mars in a pattern strikingly similar to that of the western United States, which includes the Colorado Plateau. We have identified a counterpart to the Colorado Plateau, the Loess Plateau (including the Ordos Basin) located to the west-southwest of Beijing China, and northeast of the Himalayas. Both the Colorado Plateau and the Loess Plateau developed in dynamic plate-tectonic settings of Earth which included plate subduction, major crustal deformation and shortening, magmatic upwelling, and the generation of both mafic and felsic (e.g., granite) magmas. At the conference, we will compare the geologic settings of three plateaus and their surroundings, including evidence for a mobile Martian lithosphere. In addition, we will discuss the importance of future targeting ancient (Hadean-age-equivalent) basement and sedimentary records of Mars.

References: [1] Dohm, J.M., and Maruyama, S. (2014) Habitable Trinity. Journal of Geoscience Frontiers, DOI: 10.1016/j.gsf.2014.01.005