Recent development in the upper albian ammonoid stratigraphy of the cauvery basin, south india

Abstract

This study leads to formulation of Puzosia (Puzosia) mayoriana Zone, Anagaudryceras kayei Zone and Mariella (Mariella) bergeri Zone in ascending order in the Upper Albian succession of the Cauvery Basin, south India. This endeavor incorporates ever achieved biostratigraphic refinement over the earlier works and precise differentiation of the Upper Albian succession belonging in part to the Karai Formation of the basin. The present study is based on the collection of diagnostic Upper Albian ammonoids from Karai and Odiyam stratigraphic sections of the Karai Formation. The youngest Mariella (Mariella) bergeri Zone is formulated for the relatively ammonoid rich upper part of the Upper Albian succession in the Odiyam Section. This zone is also recognized and retained in the Karai Section, however, this interval is poorly fossiliferous in the Karai Section. The above Upper Albian zones/subzones of the Cauvery Basin have been correlated with the Upper Albian standard ammonoid zonal framework and also with zonal framework of the Cauvery Basin developed by early workers. © 2025, Wadia Institute of Himalayan Geology. All rights reserved.