IMPLICATIONS OF SOFT-SEDIMENT DEFORMATION STRUCTURES WITHIN TIDAL RHYTHMITES, NIMAR SANDSTONE, CENTRAL INDIA

Abstract

The Late Cretaceous (Cenomanian to Coniacian) marine sediments of central India, prevalently known as 'Bagh Group' and have been deposited in the E-W extending Narmada Basin. Nimar Sandstone Formation of Bagh Group records various types of tidal features such as laterally and vertically accreted strata bundles, bi-directional (opposite) crossstrata bundles, lenticular bedding and wavy bedding and thin, horizontal, sandstone—mudstone alternations or inclined heterolithic strata bundles (IHS) within tidal rhythmites, central India. These tidal features suggest prevalence of marine environmental conditions during Late Cretaceous in peninsular India. These tidalites preserve various syn-sedimentary deformation features, viz., convolute lamination, flame structures, contorted bedding, pseudonodules, and syn-sedimentary faults, slump structure, water escape structures and graben-like downsagging structures. Detailed analysis of these soft-sediment deformation structures will throw some light on the depositional environments and evidences of seismic activity related to tectonicsedimentary changes within the basin during the deposition of the Nimar Sandstone sequence.