Geochemistry and Origin of the Kellampalle Lamprophyre, Prakasam Province, Andhra Pradesh

The lamprophyre (sannite) of Kellampalle (KL) occurs as a plug in tholeiitic gabbro. The KL has phenocrystic amphibole and biotite ± clinopyroxene and, groundmass amphibole, biotite and orthoclase perthite, with accessory apatite and opaques. The major, trace and rare earth element geochemistry of the KL suggests that it does not represent a directly crystallized product of a primary magma. The data suggests that a primary magma, as produced by low degrees of partial melting of metasomatised mantle; underwent olivine fractionation (prior to the emplacement) and subsequently differentiated into the cpx-bearing and cpx-free lamprophyre plug.