Emplacement of the youngest flood lava on Mars: A short, turbulent story

0019-1035/$ see front matter 2009 Published by doi:10.1016/j.icarus.2009.09.011 * Corresponding author. Address: US Geological Su Program, 2255 N. Gemini Dr., Flagstaff, AZ 86001, Un E-mail address: [email protected] (W.L. Jaeger). Recently acquired data from the High Resolution Imaging Science Experiment (HiRISE), Context (CTX) imager, and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter (MRO) spacecraft were used to investigate the emplacement of the youngest flood-lava flow on Mars. Careful mapping finds that the Athabasca Valles flood lava is the product of a single eruption, and it covers 250,000 km of western Elysium Planitia with an estimated 5000–7500 km of mafic or ultramafic lava. Calculations utilizing topographic data enhanced with MRO observations to refine the dimensions of the channel system show that this flood lava was emplaced turbulently over a period of only a few to several weeks. This is the first well-documented example of a turbulently emplaced flood lava anywhere in the Solar System. However,MRO data suggest that this same process may have operated in a number of martian channel systems. The magnitude and dynamics of these lava floods are similar to the aqueous floods that are generally believed to have eroded the channels, raising the intriguing possibility that mechanical erosion by lava could have played a role in their incision. 2009 Published by Elsevier Inc.