Ecostratigraphic implications of a Late Palaeocene shallow-marine benthic community from the Jaintia Hills, Meghalaya, NE India

摘要

Moderately preserved shallow-marine extinct, fossil benthic community has been recovered from a sub-surface Late Palaeocene limestone cave section near Lumshnong in the Jaintia Hills, Meghalaya, NE India. The present contribution focuses on the ecostratigraphic implications of the carbonate microbiofaciesbased on the evaluated facies gradients. Precise field assessments and microscopic observations led to the identification of three microbiofacies: benthic foraminiferala??algal grainstone, coralline algal framestone and oolitic grainstonea??packstone. The microbiofacies distinguished in the study suggest a general shallowing-upward trend from an inner shelf setting to a lagoonala??shoal environment depicting the distinct changes in the benthic community. Presence of coralline alga Distichoplax biserialis and benthic foraminifera Idalina sinjarica, Daviesina khatiyahi, Miscellanea primitiva, Rotalia trochidiformis and Vania anatolica assign the studied carbonates to Early Thanetian (SBZ 3) corresponding to the lower part of the Lakadong Limestone. In this study, ecostratigraphy has facilitated the classification of a single carbonate section corresponding to a solitary shallow benthic zone into multiple microbiofacies attributedto variable environmental depositional conditions. This clearly demonstrates its potential in improving the applicability of biostratigraphy worldwide.