Geomorphologic Characteristics of Polygonal Features on Chloride-Bearing Deposits on Mars: Implications for Martian Hydrology and Astrobiology  

作　　者：Binlong Ye Jun Huang Joseph Michalski Long Xiao 

机构地区：[1]Planetary Science Institute, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China [2]Department of Earth Sciences and Laboratory for Space Research, University of Hong Kong, Hong Kong 999077, China

出　　处：《Journal of Earth Science》2019年第5期1049-1058,共10页地球科学学刊（英文版）

基　　金：supported by the National Scientific Foundation of China(Nos.41403052,41773061,41830214);the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(Nos.CUGL160402,CUG2017G02);the Lunar and Planetary Science Laboratory,Macao University of Science and Technology Partner Laboratory of Key Laboratory of Lunar and Deep Space Exploration,Chinese Academy of Sciences(Nos.039/2013/A2,121/2017/A3);supported by the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.201610491122)

摘　　要：Over 600 chloride-bearing deposits(chlorides) have been identified on the southern highlands of Mars. These chlorides have critical implications for hydrology and astrobiology: they are indicators of an evaporating super saturated solution, and they could have provided habitat environments for halophilic microorganisms and preserved organic matter. One of the prominent geomorphology characteristics of these chloridebearing regions is the polygonal features within them. The origin of these polygonal features is still in debate. In this study, we have surveyed 153 locations of chlorides using 441 high resolution imaging science experiment(Hi RISE) images to characterize the geomorphology of polygonal features. We identified 3 types of polygonal features of distinct geomorphologic characteristics: fractures, raised ridges, and transitional polygons between fractures and raised ridges. We evaluate previously proposed hypotheses of the formation of the polygonal features, and suggest that the 3 types of polygonal features are indicators of different stages of salt crust formation. Salt crust is usually formed through multiple groundwater activities, and it often occurs in playa environment on Earth. The unique hydrological and astrobiological implications of the chlorides with polygonal features make these deposits of high priority for future landed on and/or sample return exploration missions of Mars.Over 600 chloride-bearing deposits(chlorides) have been identified on the southern highlands of Mars. These chlorides have critical implications for hydrology and astrobiology: they are indicators of an evaporating super saturated solution, and they could have provided habitat environments for halophilic microorganisms and preserved organic matter. One of the prominent geomorphology characteristics of these chloridebearing regions is the polygonal features within them. The origin of these polygonal features is still in debate. In this study, we have surveyed 153 locations of chlorides using 441 high resolution imaging science experiment(Hi RISE) images to characterize the geomorphology of polygonal features. We identified 3 types of polygonal features of distinct geomorphologic characteristics: fractures, raised ridges, and transitional polygons between fractures and raised ridges. We evaluate previously proposed hypotheses of the formation of the polygonal features, and suggest that the 3 types of polygonal features are indicators of different stages of salt crust formation. Salt crust is usually formed through multiple groundwater activities, and it often occurs in playa environment on Earth. The unique hydrological and astrobiological implications of the chlorides with polygonal features make these deposits of high priority for future landed on and/or sample return exploration missions of Mars.

关 键 词：chlorides polygonal feature PLAYA HYDROLOGY ASTROBIOLOGY MARS 

分 类 号：P[天文地球]