MSL at Gale Crater: What do the clays tell?

One of the key reasons of the selection of Gale crater as the MSL landing site is the presence of clay minerals in several thin beds of its lower member (Milliken et al. 2010). The presence of sulfate-bearing beds below and above the clay-bearings beds however makes the origin of clay minerals at Gale ambiguous. Previous and ongoing analyses of CRISM and OMEGA show that the Martian clay minerals have very diverse compositions and geological settings. We will present new evidences of clay mineral formation cycles during early Mars, which have similarities with the present Earth clay cycles. We will thus connect the aqueous-related characteristics of Gale to the Martian global clay cycle in order to better constrain the formation processes of clays at Gale and to relate the future MSL observations to planetary scale processes relevant to past habitability.