Chapter 4 Lithostratigraphic, geochronological and depositional framework of the Precambrian basins of the Aravalli Mountains and adjoining areas, Rajasthan, India

Abstract

Abstract The Aravalli Mountains and neighbouring areas have well-preserved records of a protracted history of development of Precambrian basins, which spans about 2500 myr of the Earth's history. The oldest depositional basins are the greenstone belts that occur within the Archaean gneiss–granite terrain. Geochronological data indicate evolution of one such greenstone belt from 3300 to 2850 Ma. The younger Proterozoic cover successions include the Aravalli Supergroup, Delhi Supergroup and Sirohi Group, which evolved during three successive orogenic cycles spanning between c. 2200 and c. 1850 Ma, c. 1700 and c. 1450 Ma, and c. 1000 and c. 850 Ma, respectively. Each of these lithostratigraphic units evolved in separate basins having distinctive tectonic, metallogenic and evolutionary histories. The inversion of the youngest ‘orogenic’ basin marks the final cratonization of the Precambrian Aravalli crust at around 850 Ma. The succeeding depositional episodes include formation of ephemeral basins during the early phase of the plume-related Malani Group from 780 to 730 Ma, and the formation of the Marwar Supergroup deposited in stable platformal basins marks the terminal phase of the Precambrian crust-building history in the region.