RUSSIAN JOURNAL OF EARTH SCIENCES, VOL. 20, ES3006, doi:10.2205/2020ES000666, 2020
P. Ramesh Chandra Phani, Prabir Sengupta, Sudeshna Basu
This paper addresses geochemical and petrological aspects of two outcropping kimberlites (5023 and 5119) of the Gooty cluster, emplaced in carbonate sediments of Vempalli Formation of lower Cuddapah basin at Krishtipadu, Anantapur district, Andhra Pradesh, southern India. These pipes were discovered by the Rio Tinto Exploration Group in the recent past. The 5023 kimberlite is enriched in olivine and serpentine while the 5119 pipe possesses haematitised olivine pseudomorphs. The field, textural characteristics and whole rock geochemistry qualify both the pipes for hypabyssal kimberlite breccias of Group-I type similar to world's classical occurrences. The carbon and oxygen stable isotope data, aided with field and petrological studies, indicates existence of possible carbonatite (sovite) phase associated with the 5119 kimberlite. The two kimberlites appear to be originated from a low degree of partial melting ranging from 0.5 to 2.5%. Enrichment of LREE with a high LREE/HREE ratio indicates fractionation at the mantle source region. Whole rock geochemistry supports their diamondiferous nature. Presence of crustal xenoliths post-dates subsequent emplacement of the two pipes to lower Cuddapah sedimentation (2.4 Ga), manifesting kimberlite magmatism. These pipes are the only known Group-I kimberlites from the Proterozoic Cuddapah Basin and therefore warrant detailed investigations.
Received 16 January 2019; accepted 19 August 2019; published 12 June 2020.
Citation: Phani P. Ramesh Chandra, Prabir Sengupta, Sudeshna Basu (2020), Geochemistry and petrology of two kimberlites at Krishtipadu from Gooty cluster, Andhra Pradesh, southern India – evidence of kimberlite magmatism and a possible carbonatite association within Palaeoproterozoic lower Cuddapah basin, Russ. J. Earth Sci., 20, ES3006, doi:10.2205/2020ES000666.
Copyright 2020 by the Geophysical Center RAS.