A dynamic model for mare basalt petrogenesis.

A hypothesis is put forth that mare basalt petrogenesis is a consequence of the inevitable sinking of dense 4.6-4.4 b.y. late-stage, ilmenite-pyroxenite cumulates (plus or minus intercumulus liquid) into the primordial lunar interior. The fundamental control on the formation of high-Ti magmas as opposed to low-Ti magmas is the ambient temperature of the primordial interior at the time of arrival of the cumulate pods.