Sedimentary Rocks of Early Mars

Abstract

Layered and massive outcrops on Mars, some as thick as 4 kilometers, display the geomorphic attributes and stratigraphic relations of sedimentary rock. Repeated beds in some locations imply a dynamic depositional environment during early martian history. Subaerial (such as eolian, impact, and volcaniclastic) and subaqueous processes may have contributed to the formation of the layers. Affinity for impact craters suggests dominance of lacustrine deposition; alternatively, the materials were deposited in a dry, subaerial setting in which atmospheric density, and variations thereof mimic a subaqueous depositional environment. The source regions and transport paths for the materials are not preserved.

Characterization and Calibration of the CheMin Mineralogical Instrument on Mars Science Laboratory

“…The array of sediment types is stunning and the record of sedimentation points to multiple environments of deposition, ranging from what appear to be cemented units of high thermal inertia within the landing ellipse to nontronite-rich deposits near the base of the mound and a range of strata ranging from clay mineral-rich to sulfate-rich, with the latter dominating upper units. Eolian processing has distributed dune material rich in mafic igneous detritus within Gale's moat and etched yardang features from some of the middle to higher strata; eolian processes are also inferred to have filled and exhumed Gale crater in a manner similar to other comparable craters on Mars (Malin and Edget 2000). The overall history of sedimentation at Gale appears to be one of progressive desiccation along with a transition from phyllosilicateforming to sulfate-precipitating conditions (Milliken et al 2010).…”

New evidence for a magmatic influence on the origin of Valles Marineris, Mars

“…Known rock compositions/types include basalt, basaltic andesite, hematite, quartz, andesite, phyllosilicates, sulfates, layered sedimentary deposits, etc. (e.g., Malin and Edgett, 2000;Bandfield et al, 2000;Christensen et al, 2000Christensen et al, , 2001aChristensen et al, ,b, 2005Rieder et al, 2004;Gendrin et al, 2005). Therefore, there is very little confidence that SNC meteorites provide an even and unbiased sampling of the Martian surface.…”

Interior trough deposits on Mars: Subice volcanoes?

“…Most workers agree that the interior deposits are no older than Hesperian (a stratigraphic age relative to the possible Early Hesperian opening of the chasmata). Alternatively, Malin and Edgett [2000a] have suggested an ancient Noachian age, on the basis of one disclosed MOC image (M17-00467) that they believe shows the material cropping out from the wall rock. However, these outcrops were previously noted on Viking images and occur only in flatter wall gullies; thus they were interpreted as fill, pasted on or abutting wall rock [oeucchitta, 1999].…”