Journal article

New insights into the genesis of Indian kimberlites from the Dharwar Craton via in situ Sr isotope analysis of groundmass perovskite

Chad Paton, Janet M Hergt, David Phillips, Jon D Woodhead, Simon R Shee

GEOLOGY | GEOLOGICAL SOC AMER, INC | Published : 2007

Abstract

In situ Sr isotopic analyses of kimberlitic perovskite are more representative of primary magmatic compositions than conventional bulk-rock analyses of the same samples, because the latter are variably compromised by contamination and alteration processes. Bulk-rock Sr isotopic data obtained for 18 intrusions from the adjacent Narayanpet and Wajrakarur kimberlite fields of the Dharwar Craton, India, exhibit a high degree of scatter (∼0.701-0.709) and have indistinguishable initial isotope ratios. In contrast, laser ablation perovskite results display strikingly uniform and distinct initial 87Sr/86Sr compositions for each field of 0.70312-0.70333 and 0.70234-0.70251, respectively. The increas..

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