Proterozoic platform sequences of Peninsular India and supercontinent assembly

What is it about?

A group of less disturbed and unmetamorphosed ‘Proterozoic’ platformal sediment package lying over deformed and metamorphosed Archean to Paleoproterozoic basement in several parts of Peninsular India is informally termed as ‘Purana’ basins in Indian stratigraphy. The trend shift in the understanding of these basin fills in last two decades, often supported by international collaborations, has made significant advancements in respect to unconformity and ‘Sequence’ development, relationship with accretion and break-up of the supercontinents, initiation and evolution of the basins in different tectonic set ups, nature of sediment provenance, paleoclimate and paleo-weathering patterns and basin water chemistry. Geophysical backups encompassing the basins, occasionally extending up to the craton and adjacent mobile belts helped in refining the understanding on the basement structure and tectonic forcings. The present paper is an attempt towards the collation of the database generated in last two decades in order to present the status of current understanding on different ‘Purana’ basins with regard to interactions of physical, chemical and biological parameters of the Proterozoic Earth.

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Why is it important?

The apparent polar wandering curve of the Proterozoic rocks of India shows five "hairpin bends". Reorganisation of the blocks forming the Peninsular India during ~1900 Ma, ~1800 Ma, ~1500 Ma, 1400 Ma and ~1200 Ma are identified. The collision events leading to continental amalgamations took place during these events. No Major change in the organisation process was noticed between 1200 and 800 Ma.