The formation of cone chains in the Chryse Planitia region on Mars and the thermodynamic aspects of this process

Abstract

This paper considers a small region in Chryse Planitia where several subparallel chains of cones are observed. Despite many papers on small Martian cones, the mechanism of their formation is not unequivocally explained, nor the reason for their arrangement in subparallel chains. In this paper, we test a few hypotheses stating that most of the cones under consideration are the result of outgassing Martian regolith when atmospheric pressure has become too low for liquid water to be stable. This mechanism explains the existence of a series of cones outside of the main volcanic zones in the vast lowlands of Mars. Magma heating might be another factor, but our calculations show that its role was often rather limited. Some of the cones may be rootless cones. Subparallel chains of cones might be formed above several types of linear subparallel structures: e.g., outcrops of aquifers, linear outcrops, fissures resulting during landslides, linear heat sources, etc. We also found that thermal advection (i.e. gas or liquid flow) could transport heat from deep aquifers to shallow aquifers. It could enabled rapid loss of volatiles. Our research on the cycloidal structure indicates that it is an outcrop of a layer that probably extends under several hills. Moreover, our preliminary research points that similar processes may have taken place in other regions of Chryse Planitia. This conclusion is based on the observation of similar structures, e.g., cones, chains of cones, arcs of outcrops, etc. in the region.