An appraisal of crustal deformation of the East Coprates Planum, Mars

摘要

Terrestrial planets in the Solar System have been impacted by meteorites from the very beginning of their existence. Mars is a planet that preserves features of tectonic deformation as well as impact-related deformation. East Coprates Planum (ECP) is an area situated on the equatorial region located just on the south of the dichotomy boundary of Mars, which has been affected by numerous tectonic and impact events from the past. A detailed structural map of ECP was prepared focusing on the wrinkle ridges (WRs) and a few Polygonal Impact Craters (PICs) in the region. The study discusses the relationship between these two geomorphic features. The WRs (established geomorphic signatures of thrust faulting) within this area were studied and various morphometric data generated from them were used to estimate the inclination of subsurface faults and shortening across the ridges. To find out the control of pre-existing weak planes on the formation of PIC rims, the parallelism between them was studied. This study was further used as a proxy to check if there is any buried weak plane in the region and their orientation. Three sets of WRs [(i) N-S, (ii) E-W, and (iii) NNE-SSW] and a set of dykes (ENE-WSW), a solitary dyke of different orientation, and a solitary graben are present. Shortening estimates across the WRs are similar to the previous estimates from both Mars and Moon. This study reveals that along with the N-S and E-W trending WRs, a set of unexposed similar to NNW-SSE trending weak planes controlled the rim geometry of the PICs in this area.