Distribution of transition elements in crustal metabasic igneous rocks

Abstract

The study of transition elements (Ti, V, Ni, Cr, Co, Cu, Zn, Fe, Mn) and Mg in metabasic crustal igneous rocks (amphibolites, granulites, eclogites) suggests that the distribution is not specially affected by medium- and high-grade metamorphism. In some cases, anomalously low contents of Ni, Cr and Cu may be more likely related to a previous low-grade metamorphic event. It seems that the fractionation of these elements is related to initial magmatic assemblages. It is demonstrated from the elements studied that most of the metabasites have an affinity with extrusive oceanic tholeiites and continental intrusive tholeiites. Thus, the subsequent high-grade metamorphism may be related either to the emplacement of basaltic magmas in the lower continental crust or to the underthrusting of the oceanic crust.