Chapter 5 Controls on sedimentation in Indian Palaeoproterozoic basins: clues from the Gwalior and Bijawar basins, central India

Abstract

AbstractOverlying Archaean Bundelkhand Granite Gneiss Complex, the Gwalior and Bijawar Groups of rocks represent two Palaeoproterozoic basin successions which, despite their common sediment provenance and analogous rift-related tectonic setup, record more dissimilarity in their sedimentation pattern than similarity. Whereas early sedimentation in the Gwalior Basin is clastic, the early Bijawar sedimentation is dominantly chemogenic (limestone and chert) except for an early, restricted volcano-clastic record. Although both of the basins record syn-depositional volcanic/volcaniclastic event(s) in the form of occurrence of basaltic and basaltic–andesite sills encased within their respective basin fills, the occurrence of iron formation in the later part of Gwalior sedimentation history and its absence in the Bijawar succession is related to variable oxidation conditions in the water columns of the two basins. Rising sea-level and upwelling on the continental margins of these two rift-related basins possibly generated different water chemistries; these allowed the deposition of iron formation in the Gwalior Basin and phosphorite in the Bijawar Basin. Effects of post-depositional digenetic re-crystallization are noticed within both iron formation and phosphorite deposits present in the basin successions.