We have recently come across a unique set of samples from the deeper crust of Mars, kilometres below what was the Gale Lake 4 billion years ago. This sample – called Askival after similar rocks from the Isle of Rhum in Scotland – formed from crystals settling down through or rising through a magma body. The light toned grains are a mineral called feldspar. One of the curious features about Askival is that it is very silica-rich suggesting that aqueous solutions altered the rock. Finally an impact in the martian ancient highlands must have excavated the samples from the crust and dropped them as impact ejecta onto the surface of Gale.
Askival cumulate from the deep martian crust. Image from ChemCam/IRAP/MSL
Subscribe to jbridges's posts
Comments are closed, but trackbacks and pingbacks are open.