The SNC Meteorites We have another source of material from Mars, and one which we can examine in the laboratory. There is a group - or rather 3 groups - of meteorites believed to originate on Mars, known as the SNC Meteorites. The SNC refers to the names of the 3 sub-groups: Shergottites, Nakhlites and Chassignites (each named after the first example of each found). These are young compared with other asteroidal material (800Myr to 1.3 Gyr) and contain shock-melted glasses. Because the material in the rocks has been differentiated and shows signs of heating, it is fairly certain t he rocks had to come from a fairly large body. Dynamically it is difficult to see materidifficult to see material reaching the earth after being thrown off satellites of the gas giants. It is unlikely, even ignoring their ages, that asteroidal material could have been hea ted enough to form the rock, so that leaves Mercury (ruled out really because of the problems with the dynamics of reaching Earth from that far in to the sun), Mars, Venus and the Moon. Even Venus is problematic
This is the end of the preview. Sign up
access the rest of the document.