“The spatial distributions of degraded craters and valley networks on Mars as a function of elevation: Their implications for Noachian climate”

Abstract

Cold and dry models of Noachian Mars postulate that the Noachian epoch characterized a hyperarid and frigid world dominated by low-latitude cold-locked icefields. This ice caps supposedly protected underlying substrates and topography of the Southern Highlands from erosional degradation. I test the Late Noachian Icy Highlands (LNIH) hypothesis by mapping small distribution of both degraded and fresh [2–4] km diameter craters, crater depth and infilling of the smallest [2–5] km craters, valley network (VN) and inverted channels within an area of interest (AOI) representing over 1.1 × 107 km2 of the Noachian Southern Highlands utilizing Environmental Systems Research Institute (ESRI) ArcMap, clipped exclusively to Noachian terrain. Crater degradation results from this study do not show preferential preservation of fresh craters at elevation. Also, crater rim – crater floor (km) depth values show greatest erosion at elevations >1 km purported LNIH Equilibrium Line Altitude (ELA). VN and inverted channels likewise give evidence for net precipitation and erosion at elevation and net deposition and water transport below the global dichotomy at 0 km and extinction at −2.78 km. VN distribution patterns also requires an intertropical convergence zone (ITCZ). I propose that my results are most consistent with emerging PMGCMs incorporating atmospheric collision-induced-absorption (CIA) of CO2 and H2, bypassing the Faint Young Sun Paradox. I propose that statistical evidence derived from geomorphological features on Mars should be used as boundary conditions for future Mars global climate models.