The hardgrounds of the Turonian–Coniacian carbonates of the Bagh Group of central India

The Upper Cretaceous of central India is represented by a thin transgressive-regressive succession of tropical marine sediments deposited on a Precambrian basement and covered by massive Deccan Trap basalt flows. At the height of the transgression, a few meters thick succession of very thinly and rhythmically bedded, laterally continuous, muddy carbonates of the Turonian–Coniacian Bagh Group was deposited. The planar to wavy beds consist of nodular to massive limestones intercalating with marls. Eroded, bored, and encrusted hardgrounds occur at regular intervals in succession. Field appearance, results of thin-section petrography, and stable isotope signature of micro-sample carbonates suggest that the hardgrounds formed in a supra- to very shallow sub-tidal, restricted marine environment, which was characterised by repeated emergence and soil genesis. Knowing moments of zero-sea level in a regular rhythmically bedded succession with accurate chronostratigraphy allows for better reconstruction of Indian intracratonic basin dynamics during the Upper Cretaceous and its correlation to global events