Episodic Emergence of Offshore Shale and its Implication: Late Proterozoic Rewa Shale, Son Valley, Central India

Detailed facies analysis in late Proterozoic Rewa Shale reveals three physically distinctive facies that differ in their paleogeography. Between shoreface and outer shelf the facies types are distributed as (I) shale with thin siltstone/Fine sandstone interbeds of outer shelf, (II) shale interbedded with HCS bearing sheet sandstone of inner shelf within storm wave base and (III) sandstone interbedded with silty shale of distal shoreface paleogeography. High resolution facies succession analysis reveals three different orders of depositional cyclicity, the lowest of which may be correlated with third order depositional 'sequence'. Thin (av 3 5 cm) discrete levels of emergence with their invariable associations and sharp transitions from inner shelf to shoreface facies mark the subaerial discontinuities, which punctuate the apparently monotonous. Rewa Shale succession Far from the coastline on a siliciclastic ramp that lacks shelf slope break, these features, even though cryptic, can provide important clues for sea level falls in shale dominated successions.