Gary Gilligan sent in the following link – www.dailymail.co.uk/sciencetech/article-3161511/A-home-home-Curiosity-fi… … which is a comparison of Mars with the Earth. Gary asks – does it also have a rich silica Mantle? However, the article emphasizes that feldspar and quartz were present, similar to the granite of the Earth. There is a theory out there about the formation of granite – as a result of catastrophism, but the take by the geologists back home is that if Mars has a crust like Earth it may also have Plate Tectonics – which appears to be a stretch. We may wonder what they will say if Mars has a crust similar to the continents on the Earth, yet has no Plate Tectonics.
The same story is at http://phys.org/print356080858.html … the camera on the Curiosity Rover robot driver that is currently exploring the surface of Mars (or a small part of the surface) has been digging into the rocky top layer and it has revealed the crust has similarities to that of the Earth. Igneous rock is also evident.
Another post at Phys Org (commenting on another recent paper) says that Mars may not have had oceans or rivers – but it may have been an icy world. The melting of the ice (by whatever means) provided the meagre water present on the planet and also allowed that same water (and ice) to be locked in the crust (although Curiosity Rover is not encountering such ice). The findings will be pored over for years so we can expect lots of articles and theories on the geology of Mars to develop over time.