Wednesday 17th October Sol 70

We go on a field trip to the Mojave Desert.  This area of California contains alluvial fans, volcanic rocks, ancient lakes and hydrothermally altered rocks.  It is also an area of little rainfall so it is in some respects an analogue for the Mars surface and the processes that have shaped Gale Crater.  The use of terrestrial analogues is one of the essential ways of understanding the formation of the terrain we are studying with Curiosity.

At this time in sol 70 it is worth recapping why the 155 km diameter Gale crater was chosen for MSL’s landing site.  Gale (like other large martian impact craters) dates from around the time of the so called Heavy Bombardment 3.8 billion years ago  when a high number of comets entered the inner Solar System and left the cratered surfaces that we see today on the ancient highlands of Mars.  Gale has had a long and complex history.  We know from the Jake_Matijevich sample that it contains an igneous history and we know from the Hottah deposits that it also contains an alluvial history.  One of the other processes that might have occurred is impact heating due to the great energy released during the Gale impact.  Untangling these processes will take all the MSL  instruments’ data and the comparison to terrestrial analogue sites.