The thumbprint terrain: What will Mars Observer tell us?

摘要: Some of the more puzzling features seen on Mars are those known as curvilinear or 'thumb print' terrain, types patterned ground found in northern plains. The thumbprint named for its resemblance to lines a human is what appears be level, relatively low-lying near crustal dichotomy boundary. It often termini large channels. There three terrain classification Rossbacher and Judson. first consists ridges depressions about kilometer wide, separated by few kilometers, with an apparent relief 40-100 m. second steep-sided, flat-floored 10-290 third only albedo markings, typical scale kilometer. Many models were proposed explain origin this terrain. was suggested that it caused lava flows, removal debris mantles, glaciers, karst. However, most popular at present involve action subsurface ice form such thermokarst striped ground, solifluction lobes, and/or linear, ice-cored ridges. several instruments Observer spacecraft will able provide us information useful distinguishing between these models.