Alkali magmatism on Mars: an unexpected diversity

Despite an apparent north/south topographic dichotomy that formed >4.0 Ga, the young Martian meteorites (<2.4 Ga) and first-order remote sensing observations revealed a surface of Mars is uniformly basaltic. This simplistic vision has been challenged by discovery brecciated meteorite additional spacecraft data all point to presence alkaline igneous rocks, thereby demonstrating unexpected diversity on Mars. In present paper, we review variety effusive rocks (basalts trachytes) recognized so far in southern hemisphere as observed from unique 4.47 Ga meteorite, well ground, orbital data. The complementary plutonic orthopyroxene-rich early discussed. We propose mantle-derived magmas at high extent melting rather low pressure either erupted forming lavas, or crystallized shallow crustal depths, fractionating orthopyroxene which sank bottom chamber residual Widespread fractionation processes could also be related heavy bombardment crust generating melt sheets ultimately differentiated. Noachian more diverse than being merely