Oxfordian ammonites from Dhosa Oolite of Jara Dome, western Kachchh, India

摘要

The study area, Jara Dome comprises the rocks of the Mesozoic age, which is situated on the northwestern fringe of the northern flexure zone of the Kachchh Mainland. The present study addresses the collection and identification of ammonites from the Oxfordian succession of the Jara Dome. As per field study Member IV (Dhosa Oolite) of the Jumara Formation is exceedingly fossiliferous with the most frequent fossil assemblage of ammonites. In the present findings, three genera have been identified Peltoceras, Metapeltoceras, and Perisphinctes. Total 11 fossil specimens assigned to 10 taxa are: Peltoceras ponderosum, Metapeltoceras armiger, Metapeltoceras cf. kumagunense, Perisphinctes (Kranaosphinctes) subevolutus; Perisphinctes (Arisphinctes) kheraensis; Perisphinctes (Arisphinctes) polymorphus; Perisphinctes (Arisphinctes) cf. trifidus; Perisphinctes (Dichotomoceras) sparsicostatus; Perisphinctes (Dichotomoceras) virguloides; Perisphinctes (Dichotomoceras) rotoides. Consequently, based on the occurrence of plentiful ammonites in one horizon and coeval stratigraphic distribution reaffirms the age of the fossils as an Oxfordian age.