Sedimentation modelling as a proxy tool for reconstruction of a mixed energy coastal shallow marine depositional system Evidence from Neoproterozoic Simla Group Western Lesser Himalaya

Abstract

Traces of Proterozoic events preserved in the stratigraphic record attract much attention from newlinegeoscientists as they provide answers to questions related to palaeotectonic reconstructions, syntectonic sedimentary successions and the evaluation of earthquake hazards. In the early part of newlinethe Proterozoic, evolution of stable cratons and the earliest supercontinents aided by the reducing newlinenature of the atmosphere produced sediments with mature composition. Transition from the Archaean to the Proterozoic is marked by changes in configuration, nature of atmosphere and newlinehydrosphere, changes in thickness, proportion and tectonic intensity of continental and oceanic crust, geochemical and isotopic compositional changes of continental lithosphere, resulting newlinesediments and biotic evolution. Several workers have concentrated on the various continental depositional environments throughout the globe. Depositional profile models for ancient coastal and shallow marine successions have also been established separately by various workers. However, a depositional profile model reflecting the common interplay of fluvial-wave-tideshallow marine processes has not been commonly cited this far from ancient shallow marinecoastal succession. This is partly due to the fact that the fluvial and wave dominated counterparts newlineof these ancient shallow marine-coastal successions are not well analyzed due to unavailability newlineof suitable outcrops. The area of interest in the present study lies in the Basantpur Formation and newlineChhaosa Formation (lower-middle part) constituting the lower-middle part of the Neoproterozoic Simla Group, considered to be an important stratigraphic unit of the Western Lesser Himalaya, India. The study area offers scope to access the process regime, morphological and sedimentary trends to understand the control of mixed energy components represented bytheadmixture of fluvial, tide and shallow marine processes. Outcrop based facies analysis combined with newlinesequence stratigraphy, geochemical and petrographic analysis helps to infer