Huge, CO2-charged debris-flow deposit and tectonic sagging in the northernplains of Mars

The northern plains of R lars contain a vast deposit, covering one-sixth of the planet, that apparently resulted in extensive lithospheric deformation . The center of the deposit may be as much as 2-3 km thick. The deposit has lobate margins consistent with the how of fluidized debris for hundreds to thousands of kilometers derived from highland and high-plains sources. The deposit surface lowers inward by similar to 900 m in places and is locally bordered by a bulge similar to 300 m high. Similar deformation accompanied development of Pleistocene ire sheets on Earth. The lack of burial of a la rge inlier of older terrain and the response time of the mantle to the load ing require that the deposit was emplaced in < 1000 yr, assuming that the d eposit was originally flat. We account for what may have been the largest c atastrophic erosional and/or depositional event in solar system history by invoking pore-filling subsurface CO2 as an active agent in the processes of source-rock collapse and debris flow.