Identifying the asthenospheric component of kimberlite magmas from the Dharwar Craton, India

Abstract

Bulk-rock samples of kimberlites from the Narayanpet and Wajrakarur kimberlite fields of the Dharwar Craton, India have been analysed for major and trace element composition and Nd and Hf isotope ratios. Despite the effect of post-emplacement alteration on a number of elements, the dataset allows inferences to be made regarding kimberlite petrogenesis and the nature of the magma source. It is argued that no significant compositional differences exist between kimberlites of the Narayanpet and Wajrakarur kimberlite fields, despite evidence for significantly different sub-continental lithospheric mantle domains beneath each field. In addition, Nb/U and Ce/Pb ratios are distinct from lithospheri..