Distribution of ostracode Fauna and Environment of Deposition of Early Miocene (Aquitanian-Burdigalian) Sediments in Kachchh, Gujarat

Abstract

Kachchh is a pericratonic basin in which Early Miocene sedimentation took place in a shallow marine environment. During the course of study of ostracods from these beds a detailed sampling carried out from a hill section (N 23°24',E 68°49') exposed about eight kilometres from Rampar village, towards Goyela-Matanomadh road. The sediment logical data and ostracod assemblage together reveals the fluctuation in relative sea-level. The change in ostracod assemblage in middle part indicating deepening i.e. middle shelf environment. This is followed by progressive shallowing of the basin marked by deposition of marl. The top part composed of limestone with full of mega fauna indicates again deeper water condition prevail in the area. The paleoecology of the genera viz. Actinocythereis, Neomonoceratina, Alocopocythere, Cytherelloidea, Pontocypris, Propontocypris, Pseudocythere, Semicytherura, Xestoleberis, Cytheropteron, Miocyprideis, Pokornyella and Occultocythereis is discussed in the paper.The overall evidence suggests that majority of the genera thrive well in near-shore to shallow marine environment and hence it is inferred that the beds of Early Miocene might have been deposited in near-shore to shallow marine conditions.