5 EASY PIECES: THE ASSEMBLY OF PENINSULAR INDIA

In a seminal 1988 paper, Paul Hoffman addressed the sequencing of collisional events resulting in the assembly of the Laurentia nucleus. The core Archean blocks of Laurentia appear to be connected by a series of orogenic belts that led to final coalescence by ~1.7 Ga. Hoffman’s premise was confirmed, at least in part, by comprehensive studies of well-dated paleomagnetic poles from these individual blocks. India is composed of several major cratonic regions that are dissected by mobile belts marking the edges of the cratonic nuclei. The North India Block (NIB) consists of the Aravalli Banded Gneiss Complex and Bundelkhand craton and the South India Block (SIB) is made up of the Singhbhum, Bastar and Dharwar cratons. The Dharwar and Bastar cratons are geographically separated by the Prahnita-Godavari Rift (PG), the Singhbhum and Bastar cratons by the Mahanadi Rift (MR) and the combined Bastar/SinghbhumDharwar region is separated from the Bundelkhand/Aravalli cratons by the Central Indian Tectonic Zone (CITZ). The CITZ is an ENE-WSW trending polymetamorphic region that cuts across India. In addition to the cratonic regions cited above, a large granulite region lies to the south of the Dharwar craton. The so-called ‘southern granulite terrain’ is a collection of highly metamorphosed crustal blocks of Archean to Neoproterozoic age in southern India to the south of the Dharwar craton. In this talk, we review the complexities of the structural/metamorphic history of the CITZ; the craton bounding orogenic belts and results from paleomagnetic studies to shed some light on the assembly history of Peninsular India. Based on these combined databases, we conclude that most of Peninsular India was assembled by at least 1.0 Ga, but we will argue that the assembly of these 5 easy pieces occurred much earlier.