A REFINED METHOD FOR TRACE-ELEMENT MODELING OF NONMODAL BATCH PARTIALMELTING PROCESSES - THE CENOZOIC CONTINENTAL VOLCANISM OF CALATRAVA, CENTRAL SPAIN

A refined method for quantitative trace element modelling of partial m elting processes is proposed here. This method is based on a two-part approach: (1) From binary diagrams and a minimal number of assumptions , a set of constrained values of the parameters (F, D-0(i), P-L(i), C- 0(i)) are constrained for selected trace elements; (2) A simultaneous best-fit solution is obtained for those elements, which is then used t o calculate the parameters for the remaining trace elements. This appr oach eliminates much of the mathematical complexity of other inversion techniques as well as the necessity of assuming values for poorly con strained parameters (e.g., mineral/liquid distribution coefficients). This method was succesfully applied to the primary melilitites, nephel inites, and olivine basalts from Calatrava, central Spain. The results of this calculation suggest that this basaltic suite was generated fr om a homogeneous garnet Iherzolite with phlogopite that was enriched r elative to chondrites up to 18 times for the highly incompatible eleme nts and about 3 times for the moderately incompatible. This source und erwent progressively higher melting degrees between 5% (melilitites) a nd 17% (olivine basalts).