THE FLOOR OF GALE CRATER, MARS: LAVAS, NOT LAKES?

The next Mars rover, Curiosity, is scheduled to land on the floor of Gale crater (5°S, 138°E) in August, 2012. Gale crater was selected because it contains a 5-km-tall layered mound that may reveal information about Mars’ paleoclimate, and because Gale crater’s morphology is consistent with it having once contained a lake. Gusev crater, landing site for the rover Spirit, was also chosen because its morphology suggested a paleolake; however, Spirit landed on basaltic lava flows instead of lacustrine sediments. Analyses of high-resolution (<25 cm/pixel) images from the High-Resolution Imaging Science Experiment (HiRISE) and the Mars Reconnaissance Orbiter Context Camera (CTX) of Gale crater’s floor between the layered mound and the north rim reveal morphologies that are similar to those observed on the floor of Gusev crater. I will present geologic evidence supporting the hypothesis that the floor of Gale crater contains low-viscosity lavas, like those Spirit encountered at Gusev crater. If correct, this hypothesis has implications not only for Curiosity’s exploration, but also for the widespread volcanic history of Mars.