Resumen de Carbon and oxygen isotope profiles from the terminal precambrian Marwar Supergroup, Rajasthan, India
Anil Maheshwari, Alcides N. Sial, S.C. Mathur
Results of carbon and oxygen isotope studies from early Cambrian unfossiliferous carbonates belonging to the Marwar Supergroup, western Rajasthan, India are presented. The carbonates are enriched in "heavy" d18O values (upto +6.50%o PDB) and rules out the diagenetic modifications of isotope signals. The multiple, shortterm negative (upto -10.31%o PDB) and positive (upto +2.80%o PDB) carbon isotope oscillations observed in Marwar carbonates well matches with the lower Cambrian (Nemakit-Daldynian) carbonates reported world wide and these oscillations have been attributed to the result of climatic oscillations either from glaciations or from "cold house phases" that did not involve major glaciations.
