Giant ooids in a Neoproterozoic carbonate shelf, Simla Group, Lesser Himalaya, India: An analogue related to Neoproterozoic glacial deposits

Giant ooids associated with Neoproterozoic glacial deposits throughout the world, occupy stratigraphic positions below, above or between glaciations. Simla Group is another example where giant ooids lie stratigraphically below Marinoan Blaini Tillites. Increased magmatic activity and weathering before and during the Neoproterozoic glaciations increased nutrients in marine waters which increased algal growth. Thus, giant ooids were deposited due to such phases of increased microbial activity before/after glaciation, and during interglacial periods.