E-catalog        

Large igneous provinces (LIPs) and especially their dyke swarms are pivotal to reconstruction of ancient supercontinents. The Dharwar craton of southern Peninsular India represents a substantial portion of Archean crust and has been considered to be a principal constituent of Superia, Sclavia, Nuna/Columbia and Rodinia supercontinents. The craton is intruded by numerous regional-scale mafic dyke swarms of which only a few have robustly constrained emplacement ages. Through this study, the LIP record of the Dharwar craton has been improved by U-Pb geochronology of 18 dykes, which together comprise seven generations of Paleoproterozoic dyke swarms with emplacement ages within the 2.37–1.79 Ga age interval. From oldest to youngest, the new ages (integrated with U-Pb ages previously reported for the Hampi swarm) define the following eight swarms with their currently recommended names: NE–SW to ESE–WNW trending ca. 2.37 Ga Bangalore-Karimnagar swarm. N–S to NNE–SSW trending ca. 2.25 Ga Ippaguda-Dhiburahalli swarm. N–S to NNW–SSE trending ca. 2.22 Ga Kandlamadugu swarm. NW–SE to WNW–ESE trending ca. 2.21 Ga Anantapur-Kunigal swarm. NW–SE to WNW–ESE trending ca. 2.18 Ga Mahbubnagar-Dandeli swarm. N–S, NW–SE, and ENE–WSW trending ca. 2.08 Ga Devarabanda swarm. E–W trending 1.88–1.89 Ga Hampi swarm. NW–SE ca. 1.79 Ga Pebbair swarm.Comparison of the arcuate trends of some swarms along with an apparent oroclinal bend of ancient geological features, such as regional Dharwar greenstone belts and the late Archean (ca. 2.5 Ga) Closepet Granite batholith, have led to the hypothesis that the northern Dharwar block has rotated relative to the southern block. By restoring a 30° counter clockwise rotation of the northern Dharwar block relative to the southern block, we show that pre-2.08 Ga arcuate and fanning dyke swarms consistently become approximately linear. Two possible tectonic models for this apparent bendi