Like olivine, pyroxene results from volcanic processes that trace the evolution of the planet’s interior, its chemical composition acting as a tracer of the evolution of the temperature and pressure inside the planet.
Pyroxenes are particularly widespread in the cratered highlands, pointing to some of the most ancient portions of the planet’s crust. In the smooth northern plains, the pyroxenes reflect the eruption of more evolved lavas compared to the pristine magnesium-rich olivines. The change in composition over time suggests that older lavas may have had higher temperatures than younger lavas.
The colour scale represents the abundance of pyroxene, from low (blue) to high (red).
This map was released on the occasion of the tenth anniversary of the launch of Mars Express, along with global maps of hydrated minerals, olivine, ferric oxide and dust. Click to access the required image.