22nd July 2014 Sol 696

Recently MastCam and ChemCam imaging revealed 2 iron meteorites along our traverse.  These are the first found by Curiosity, though the 2 MER, Spirit and Opportunity also identified iron meteorites.

The Curiosity ones: called Lebanon and Littleton were identified by their high reflectivity (‘specular’) compared to the other rocks, native to Gale Crater. They are < 1 m across. 

The freshness of the meteorite surfaces suggests that they have not been exposed to the water and salts that the mudstones and other sedimentary rocks experienced. 

An interesting puzzle is that we have only ever seen iron meteorites on Mars.  Stony meteorites are by far the the most common sort on Earth and were also identified on the lunar surface by Apollo 17.  Was there a recent break up of an iron meteorite parent body which led to a shower of meteorites on Mars or is it that the shiny surface enables us to identify iron metorites, but stony meteorites are more difficult?

The image below shows a ChemCam RMI image superimposed on a Mastcam image.  The pitted surface shows regmaglypts, which are caused by the passage of a meteorite through an atmosphere. The action of sand carried by the wind in reecnt times on the surface of Mars may have enhanced these features.