This study investigates the geochemical and isotopic characteristics of Jurassic kimberlites and ultramafic lamprophyres (UMLs) from four clusters within the Adelaide Fold Belt (AFB) and two within the Gawler Craton in South Australia. Petrographic analysis, including the occurrence of magmatic clinopyroxene in the groundmass, supported by a review of available mica and spinel compositional data, indicates that many previously...

The role of mantle vs. crustal contributions to A-type granitoids are heavily debated, in line with the wide compositional diversity among these magma types. The Cambrian post-orogenic Venda Nova and Várzea Alegre Plutons of the Araçuaí belt, SE Brazil, turn out to represent an endmember case where the clear “crustal” isotopic signature is already present in the primitive mantle melts and hence mantle source. The mildly alkali...