Volcanism
Volcanic structures and landforms cover large portions of the Martian surface. The most conspicuous volcanoes on Mars occur in Tharsis and Elysium. Geologists think one of the reasons that volcanoes on Mars are able to grow so large is because Mars has sparsely few tectonic boundaries compared to Earth. Valles Marineris is a tectonic boundary, that slides horizontally. Lava from a stationary hot spot is able to accumulate at one location on the surface for many hundreds of millions of years.
On October 17, 2012, the Curiosity rover on the planet Mars at "Rocknest" performed the first X-ray diffraction analysis of Martian soil. The results from the rover's CheMin analyzer revealed the presence of several minerals, including feldspar, pyroxenes and olivine, and suggested that the Martian soil in the sample was similar to the "weathered basaltic soils" of Hawaiian volcanoes.
Read more about this topic: Geology Of Mars