Geosystems and Geoenvironment (May 2023)
Proterozoic basins of the Bundelkhand Craton, India: Correlations and significance in understanding the tectonic evolution
Abstract
The Bundelkhand Craton and associated basins of Peninsular India have received interest for debates related to research on their records of biological evolution, particularly reported occurrences of materials akin to triploblastic animals. Data related to geochronology and key tectono-stratigraphic markers of the block have been critically analysed and a model of evolution during the Proterozoic Eon is presented. The basement block, the Bundelkhand Granite Complex, evolved in three phases: Phase I (3551–3190 Ma), Phase II (2780–2550 Ma) and Phase III (2450–2250 Ma), followed by tectono-thermal events between the phases, representing temporal unconformities of ∼400 Ma and ∼100 Ma. The last phase of evolution was terminated with the amalgamation of the North Indian Block with the South Indian Block, forming the Satpura Orogen (phase IA) at ∼2250 Ma, which included the Singhbhum Orogenic belt. Orogenic collapse/extension at ∼2150 Ma developed a series of sedimentary basins running parallel to the orogenic belt. These Paleoproterozoic basins include the Mahakoshal, Bijawar, Sonrai and Gwalior basins around the Bundelkhand Granite Complex. The adjacent cratons also developed contemporaneous basins for the deposition of the Aravalli Supergroup (in the Western Indian Block), Cuddapah Supergroup (in the South Indian Block) and a proto-ocean at the site of the Eastern Ghats, extending towards the northern margin of the Singhbhum Block. All these basins had an inversion phase of 1950–1800 Ma, ending with the development of the Aravalli Orogen as well as Satpura Orogen (phase IB) and closing of sedimentation in the Paleoproterozoic basins. A new phase of extension at ∼1750 Ma initiated deposition of the Semri Group and Delhi Supergroup in the Northern and Western Indian blocks. The event was associated with the amalgamation of East Antarctic Block with the South Indian Block forming the Eastern Ghats (phase I)-Dalma Orogen. The later stage of Eastern Ghats (phase I)-Dalma Orogeny ∼1500 Ma was contemporaneous with the Delhi Orogeny (North Delhi Orogeny). The principal compressions acting opposite to each other during the Delhi Orogeny (with southeastward tectonic transport) and Eastern Ghats (phase I)-Dalma Orogeny (with northwestward tectonic transport) caused the second uplift of the Satpura Orogen (Satpura Orogeny II), as well as the uplift of the North Indian Block, developing a first-order spatio-temporal unconformity of ∼300 Ma gap above the Semri Group, till the extensional stress regime of ∼1200 Ma initiated deposition of the Kaimur Group. The closing of the Kaimur Basin took place during the Grenvillian Orogeny of ∼1100 Ma, which developed the Eastern Ghats (phase II) – Rayner Orogen on the eastern margin of Peninsular India. The far-field stress of the Eastern Ghats Orogeny (phase II) developed inversion/uplift in the Satpura Orogen and deposition of the Rewa Group in the North Indian Block. A second uplift of the Eastern Ghats (Eastern Ghats Orogeny phase II) and the Delhi Orogen (South Delhi Orogeny) at ∼1000–950 Ma closed the deposition of the Rewa Group and initiated deposition of the Bhander Group in the North Indian Block and the Sirohi Group in the Western Indian Block. The Pindwara Orogeny of ∼850 Ma in the Western Indian Block caused uplift of the North Indian Block and closed the deposition of the Bhander Group. The orogenic movements at ∼1500 Ma and ∼1100–950 Ma were associated with continental amalgamations along the western and southeastern margin of India, but did not involve any amalgamation in the central part of India, which was affected by reactivation/uplift of an older structural fabric.
