February 23
Climate Sleuthing at the Martian Poles
Speaker: Dr. Riley McGlasson, Smithsonian NASM
Abstract: Mars has extensive polar ice caps, which combined contain a similar volume of ice as Greenland, and are the largest reservoirs of water on Mars’ surface. Included in Mars' large polar caps are the north and south polar layered deposits (NPLD and SPLD, respectively) that are composed of kilometers-thick deposits of water ice. The polar layered deposits (PLDs) have been built up over the past millions of years as layers of water ice with variable dust content were emplaced at the poles. These layers record climate-driven phases of deposition and erosion throughout the lifetime of the deposit. Here, we will focus on the south polar region of Mars, which contains an older and more enigmatic geologic record than the north pole. The south pole contains at least three timescales of ice evolution in the form of the CO2-ice-dominated South Polar Residual Cap (SPRC, ~100 yrs), the SPLD (10s of Myrs), and finally the Dorsa Argentea Formation (DAF) which is thought to be remnants of an extensive ancient (>3 Gya) ice sheet.
We attempt to unravel this climate history through geologic mapping at both a regional scale covering poleward of 70ºS, as well as a highly localized scale looking at remnant layered materials within an ancient impact basin. Identifying local variations can help to constrain active polar processes and their part in the evolutionary history of some of the most ancient deposits on Mars. Our combined mapping efforts will provide necessary context for understanding the complex evolutionary history of these terrains and the climate record they represent.
Host: Ben Sharkey