Mars evolution

An overarching geologic hypothesis, GEOMARS, coherently explains many aspects of the geological history of Mars. This includes ancient geologic terrains that comprise mountain ranges, structurally-controlled basins, highly degraded promontories, magnetic anomalies, and basin-containing stacked sequences of sedimentary deposits. In addition, the theory also clarifies an ever increasingly realized mineralogically diverse planet, marine-, lacustrine-, fluvial-, eolian-, and glacial-sculpted landscapes, and superplumes that have dominated the geologic, hydrologic, and climatic histories for more than 3.5 Ga until the present. The hypothesis comprises eight major stages of martian geological evolution (from oldest to youngest): Stage 1 - shortly after accretion, Mars differentiates to a liquid metallic core, a mantle boundary (MBL) of high-pressure silicate mineral phases, upper mantle, magma ocean, thin komatiitic crust, and convecting steam atmosphere; Stage 2- Mars cools to condense its steam atmosphere and transforms its mode of mantle convection to plate tectonism; subduction of water-rich oceanic crust initiates arc volcanism and transfers water, carbonates, and sulfates to the mantle; Stage 3 - the core dynamo initiates, with the associated magnetosphere and possible photosynthetic production of oxygen; Stage 4 -accretion of thickened, continental crust and subduction of hydrated oceanic crust to the mantle boundary layer and lower mantle of Mars continues; Stage 5 - the core dynamo stops during Noachian heavy bombardment but plate tectonism continues; Stage 6 - large basin-forming impacts result in Hellas, Argyre, Isidis, and Chryse; Stage 7-plate tectonism terminates and Tharsis superplume (~between 4.0 and 3.8Ga) initiates, and Stage 8 - the superplume phase (stagnant-lid regime) of martian planetary evolution with episodic phases of volcanism, water outflows, and related transient hydrological cycling as well as climate and environmental change which interrupts prevailing ice-house conditions. This portrayal of the geological evolution of Mars, as a testable hypothesis, is highlighted through the geologic provinces of Mars and their special attributes. The provinces are (mostly from oldest to youngest, as there is an overlap in relative age among several of the provinces): the ancient southern highland province, including Terra Cimmeria, Terra Sirenum, Arabia Terra, Zanthe Terra, and the mountains ranges, Thaumasia highlands and Coprates rise, as well as the younger Hellas-Argyre province, Tharsis and other volcanic provinces such as Elysium rise, Malea Planum, Hadriaca and Tyrrhena Mons, Apollinaris Mons, and Syrtis Major, the northern plains, and the Tharsis/Elysium corridor.