9th July 2015 Sol 1039

This MastCam image shows an important close up view of the Stimson sandstone – Pahrump mudstone contact. The light clasts may be sulfate like gypsum, and broken up fragments of the sulfate veins that we have been seeing since Yellowknife Bay.  This could be important for understanding the burial and alteration history of the sediments and origin of the veining. There are 2 likely possibilities for the veins either they formed through the alteration of the mudstones or they are the product of dissolution of a pre-existing evaporite salt layer. The association with mudstone (though not exclusively – as some veining is in the coarser sandstones) may indicate that the sulphate was derived through the alteration of the mudstone during burial heating.