Middle Jurassic Calcareous Nannofossils from Type Jumara formation, Kachchh, Western India

Late Bathoman - Callovian - Oxfordian - Early Kimmendgian siliciclastic sediments of some prominent sections of Kachchh Mainland Jumara, Basal Jumara, Ler, Kanthkot, including Kuldhar Member of Jaisalmer Basin, contain discrete succession of Calcareous Nannofossil assemblage encompassing Standard Jurassic Zones NJ12 Ansulasphaera helvetica, NJ13 Stephanohthion bigotu bigotu, NJ14 Stephanolithion bigoti maximum and NJ15 Cyclagelosphaera margerelu. The Calcareous Nannofossil Zones and Events are tied to Boreal and Indian part of Tethyan Ammonite zonation 33 species of Calcareous Nannofossils were documented from the Bositra (=Posidonia) bearing basal dark grey shales of Jumara (=Chan) Formation exposed at the type area of Jumara Dome.