PSI SEMINAR SERIES: 27 October 2004, 3:30pm

"The Skeleton Upon Which Hangs the Geologic Record of Mars"

Ken Edgett

As viewed from orbit and at high spatial resolution, the geology and geomorphology of Mars is complex and diverse. Seven years of on-orbit operations of the continuing Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) investigation have provided key observations that reveal the nature of the upper 2-10 km of the martian crust, its geologic materials, and the record it represents. Ancient impact craters and fluvial valley systems are interbedded within the layered rocks that comprise the upper crust of Mars. Craters ranging from a few 10s of meters to over 100 km in diameter have been completely filled, buried, and later exhumed. Huge amounts of material, in many places more than 1 km thick, have been eroded away to give the martian surface its present form. Much of the accessible record revealed by erosion is recorded in sedimentary, rather than volcanic, rocks. MGS MOC images and results from the Mars Exploration Rover, Opportunity, demonstrate that some fraction of the sediments that make up these rocks were transported, deposited, and diagenetically altered in aqueous environments.


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