On the Depositional Environment of the Nagthat Quartzite, Lesser Himalaya

Abstract

Nagthat quartzite shows well-developed sequences of a shallow tidal sea, and represents deposits of coastal sand bar/shoal complex and mixed flats. The sand bar deposits show large-scale cross-bedding of bar type, mega-ripple bedding and abundant planes of discontinuity. The mixed flat deposits show lenticular and flaser bedding, wavy bedding, tidal bedding, small ripple bedding, parallel bedding and laminated mud. Ripples showing characteristics of shallow-water and falling water-level environments are commonly present. In a typical Nagthat quartzite, sand bar deposits and mixed flat deposits alternate with each other in a cyclic manner. The Nagthat quartzite denotes deposit of a stable shelf association.