In this overview, the Precambrian metallogeny in the Indian shield has been summarized in the backdrop of the evolution of different crustal domains and their linkages to the geodynamic history of the shield. The northern cratonic block (NCB) of the Indian shield is constituted by the Bundelkhand massif (BM), Aravalli-Delhi orogenic belt (ADOB), Shillong plateau and the Himalayan Proterozoic belts and is separated from the larger southern cratonic block (SCB) comprising the Singhbhum craton (SC), Bastar craton (BC), Dharwar craton (DC, including WDC, EDC as well as the Southern Granulite Terrain (SGT)) and the Eastern Ghat mobile belt (EGMB) by the ENE-WSW-trending Central Indian Tectonic Zone (CITZ). These two cratonic blocks are constituted by a few distinct crustal domains: the Archean cratonic nuclei and the Gneissic complexes with the granulitic or granite-greenstone
terranes and the Proterozoic mobile belts and intra-cratonic basins, along with the anorogenic volcano-plutonic complexes and mafic dyke swarms. Within the various litho-tectonic domains of the Indian shield are concentrated vast resources of iron, manganese and aluminum and notable resources of chromium, copper, lead, zinc and uranium. There are also significant reserves of gold and tungsten as well as rare concentration of tin and platinoid metals. Titanium along with thorium and other REE are now largely concentrated in coastal placer deposits. Out of these, the Al and REE (including Th and Ti) resources, although derived from Precambrian rocks, are the products of
metallogenic processes in the Mesozoic and Cenozoic eras, and have been left out of the discussion.
Metallogeny in the Indian shield spanned over a long period of 2.9 Gyr (~ 3.6 to 0.7 Ga) during five specific epochs. The earliest mineralization (+ 3.5 Ga) is recorded from a BIF in SC. Paleo- to Mesoarchean (~ 3.3 to 3.1 Ga) saw the formation of Ti-V-Fe, Cr + PGM, Au, Cu and Fe (BIF) in WDC and SC respectively. Intense and economically important metallogeny took place in Neoarchean (2.7 to 2.5 Ga) in SC, BC and DC represented by Fe, Mn, Cu-Mo, Sn, and Au and in Paleo- to Mesoproterozoic (2.2 to 1.5 Ga) in the mobile belts of SC, CITZ, ADOB and the Himalaya (Au, Cu-U, P-Fe, Mn, Zn-Pb-Cu, Pb-Zn deposits) and in intra-cratonic basins (Mn, Pb-Zn, U). In Neoproterozoic (1.0-0.75 Ga), the western fringe of ADOB saw VMS-type Zn-Pb-Cu and Zn-Cu mineralization as well as granite-related Sn-W deposits. Three of these metallogenic epochs coincide closely with Precambrian Supercontinent assembly of Kenorland (~ 2.7 Ga), Columbia (~ 1.8) and Rodinia (~ 1.0 Ga) respectively, as well as with the peaks of juvenile crustal growth in Neoarchean and Paleoproterozoic.
