Paper No. 50-2
Presentation Time: 9:00 AM-5:30 PM
PROTEROZOIC PENINSULAR INDIA: NORTH-SOUTH INDIA COLLISION
Peninsular India is an important player in the reconstruction of supercontinents Rodinia and Columbia. High resolution data is necessary in these reconstructions, such as paleomagnetic and geochronologic data. Targeted areas for such data acquisition include orogenic belts, Large Igneous Provinces (LIPs) and mafic dyke swarms. Radiating dyke swarms can be used to locate the ‘piercing point’ of individual cratons within larger supercontinent formations (Hou et al., 2008; Ernst et al., 2008; Radhakrishna et al., 2012). The mafic dyke swarm within the Singhbhum craton of NE-India can be analyzed and help limit reconstructions of Rodinia and Columbia, as well as the amalgamation of North-South Indian blocks. These dykes, commonly referred to as the Newer Dolerites, trend primarily NNE/SSW and NW/SE, with a crosscutting relationship. The geochronology of the Newer Dolerites is poor, but increasing in precision with recent publications. Shankar et al. (2014) published precise Pb-Pb ages on two NW-SE oriented of 1766.2+1.1 Ma and 1764.5+0.9 Ma, while previous K-Ar studies yielded three ages of 2100 +100Ma, 1500 + 100 Ma and 1100 + 200 Ma (Bose, 2008; and sources within). These three ages may represent different dyke intrusions, but it is unclear at the time. India was believed to be two separate blocks, the North Indian Block (NIB) and South Indian Block (SIB). We will present preliminary paleomagnetic data from the Singhbhum craton dykes and discuss the results in the context of supercontinent assembly and dispersal as well as their importance to the topic of NIB/SIB amalgamation.