Serial magmatism

Serial magmatism is a model that requires basaltic magma to erupt and intrude repeatedly into a pre-existing crust. Regarding the Moon, the magma would have been partially melted in the lunar mantle due to heat produced by initial accretion, radioactive elements, and mantle overturn. As the intruded magma cools it differentiates by density, causing heavier materials (i.e., mafic minerals) to sink down into the lunar mantle, and lighter materials (i.e., plagioclase) to rise to the crust. As each of the materials separate, they create diapirs which then sink or float to their respective positions. As each diapir solidifies, it would constitute that they would all have their own ages and geochemical signature that may allude to when each intrusion formed. This process would cover a primary lunar crust, and leave us with a complex crust where diapirs overlap and may be difficult to unravel.