Ricerc@Sapienza

A general agreement on the origin of carbonatite magma has not yet reached after more than sixty years of hot discussion. The diatribe is mostly focused on four main topics: 1) the origin of carbonatites and their relation with silicate magmas; 2) the origin of incompatible element enrichment in the most abundant carbonatitic magma (i.e., Ca-carbonatites); 3) the geodynamic implication of carbonatitic activity in terms of plate tectonics, and 4) the difficulty to distinguish true carbonatites from carbothermal/carbohydrothermal carbonatites or simple skarns.
In the last twenty years several experimental petrology studies have demonstrated that carbonatitic melts can be generated not only from partial melting of a peridotitic (i.e., olivine-rich) sources or by immiscibility from ultrabasic to intermediate silicate melts, but also from subducted carbonated eclogite (i.e., olivine-rich to olivine-poor) lithologies. These subducted lithologies are efficient carriers of carbon in the upper mantle and, depending on the thermobaric evolution of the recycled slabs, they can experience different types of interaction with the peridotiti matrix. Partial melts of recycled carbonated eclogites Several experimental studies have demonstrated that partial melts of recycled carbonated eclogites share major oxide content of classical oceanic basaltic rocks (with compositions from nephelinite/melilitite to basanite and alkali basaltic.