AbstractOur pilot study reveals potential fingerprints of Li isotopes recorded in the Mesoproterozoic (∼1.4-1.1 Ga) kimberlites, lamproites and lamprophyres from the Eastern Dharwar Craton and Paleocene (62 Ma) orangeite from the Bastar Craton in India. The new data are interpreted in the context of available Li isotope composition of lamproitic to lamprophyric rocks occurring in Variscan (Bohemian Massif) and Alpine-Himalayan (SW Tibet) orogenic belts formed in response to Gondwana-Pangea amalgamation and break-up. As a result of supercontinents development, kimberlites from the Eastern Dharwar Craton and ‘orangeite’ from the Bastar Craton show clear presence of a component with a heavy Li isotope signature (δ7Li up to 9.7‰) similar to an ancient altered oceanic crust, whereas the Eastern Dharwar Craton lamproites (2.3-6.3‰) and lamprophyres (3.3-6.7‰) show Li isotope signatures indicative of a dominant contribution from heterogeneous lithospheric mantle. Variscan lamprophyric to lamproitic rocks and post-collisional mantle-derived (ultra)potassic volcanic rocks from SW Tibet, i.e., rocks from the orogenic belts outside the cratonic areas, are characterized by a clear Li isotope shift towards isotopically lighter component (δ7Li as low as -9.5‰) comparable with the involvement of an evolved continental crust and high-pressure metamorphic rocks in their orogenic mantle source. Such components with isotopically light Li are strikingly missing in the source of cratonic kimberlites, lamproites and lamprophyres.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5495097
Bio-weathering of granites from Eastern Dharwar Craton (India): a tango of bacterial metabolism and mineral chemistry