Link between Lesser Himalayan Neoproterozoic Krol succession and the Adelaide rift complex of Australia ‒ evidence from the mudstone deposits of Krol succession, Himachal Pradesh, India

Abstract

The mudstone deposits, a major constituent of the Lesser Himalayan Krol succession, represents the terminal phase of Marinoan snowball melting, an important part of the most significant events of the Proterozoic time, the Cryogenian Snowball Earth. The Facies analysis suggests that the sediments were supplied to the shelf by meltwater flows, and were later dispersed to the deeper part of the shelf by current/wave-enhanced bottom currents. The upper part of the deposit bears the signature of gradual shallowing of the basin caused due to glacioisostatic rebound. Petrographic study of the samples, randomly collected from different parts of the deposit, reveals that the mud deposit is composed of silt-sized particles of quartz and dolomite, and argillaceous material. Besides the variation in proportion of these constituent components, no other material was found within this deposit. This compositional homogeneity of this huge deposit primarily suggest derivation from some preexisting sediments. Mineralogical similarity and perfect match in trace and Rare Earth elements composition suggest that this mud was derived from the periglacial loess deposits of the Nuccaleena Formation of South Australia. This is in agreement with the provenance of the underlying Krol Sandstone. The mudstones, along with the underlying Krol Sandstone, thus suggest that the Lesser Himalayan Krol succession represent an extended part of the Adelaide rift system of South Australia. The relative position of India and Australia during Neoproterozoic, as per the reconstructed configuration of the Rodinia supercontinent, corroborates this inference.