Very recent and wide-spread basaltic volcanism on Mars

New spacecraft data provide increasing evidence for dynamic environment on present�day Mars. Exogenic such as impact cratering, mass wasting processes, active dune migration have all been observed to modify surface. No traces of current endogenic activity have been yet, but some studies point to very localized volcanism the last few millions of years. However, no systematic of young volcanic surfaces had been performed so far. present absolute model age determinations of plains on Mars as derived from impact crater sizefrequency . Extended areas in Tharsis, the largest �tectonic region on Mars, have been resurfaced by flows in the last few tens of millions of years. We also results on the rheologic properties of these lava flows, from morphometric measurements. Yield strengths in the range of 100�300 Pa, and viscosities reach values 10^2 to 10^3 Pa s, indicating basaltic compositions. The imply that Mars retained until recently, and probably retains, enough internal heat to produce wide�spread �style volcanism, producing low�viscosity lava flows large parts of Tharsis