Growth of the Greater Indian Landmass and its assembly in Rodinia: Geochronological evidence from the Central Indian Tectonic Zone Santanu K. Bhowmik a, ⁎, Simon A. Wilde b , Anubha Bhandari a , Taraknath Pal c , Naresh C. Pant a, 1 a Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur-721 302, India b Department of Applied Geology, Curtin University, Perth, WA, 6845, Australia c Central Petrology Laboratory, Geological Survey of India, 15A-B, Kyd Street, Kolkata-700016, India abstract article info Article history: Received 15 July 2011 Received in revised form 16 September 2011 Accepted 23 September 2011 Available online 1 October 2011 Handling Editor: M. Santosh Keywords: U–Pb and Lu–Hf zircon Monazite chemical dating Central Indian Tectonic Zone Rodinia The Sausar Mobile Belt at the southern margin of the Central Indian Tectonic Zone (CITZ) is a key unit in con- straining the timing of continent–continent collision between the North and South Indian cratonic blocks. It con- sists of three domains – northern, central and southern – that record the history of this collision. Rocks from the northern and central domains were metamorphosed under medium pressure–medium temperature conditions and define a clockwise P–T trajectory. Monazite spot ages in garnet–cordierite migmatite from the western ex- tremity of the northern domain yield a weighted mean age of 1043 ± 18 Ma (MSWD = 0.26) for monazite cores and 955±11 Ma (MSWD=0.43) for monazite rims. These ages are correlated with peak granulite facies meta- morphism and post-peak decompression, respectively. Garnet–orthoamphibole gneiss and garnet–cordierite migmatite from the central and eastern sectors of the northern domain, respectively, yield weighted mean ages (for monazite) of 974±9 Ma (MSWD =0.53) and 989±9 Ma (MSWD =1.3). These ages mark the timing of retrograde metamorphism in the northern domain. Charnockite in the northern domain, which was emplaced during post-peak decompression, records a SHRIMP U–Pb zircon concordia age of 938±3 Ma (MSWD =1.9). Lu–Hf isotopic analyses of these zircons show a restricted range of εHf(T) values (from -2.9 to -5.8 with a mean of -4.3) and have T DM c model ages from 1995 to 2163 Ma (with a mean of 2064 Ma), implying derivation of charnockitic magma from a Paleoproterozoic crustal source. In contrast, garnet–staurolite–kyanite schist and garnet–biotite–muscovite–quartz schist from the central domain of the Sausar Mobile Belt yield weighted mean monazite ages of 1062 ± 13 Ma (MSWD = 1.2) and 993 ± 19 Ma (MSWD = 0.16), respectively, which are broad- ly correlated with the peak and retrograde stages of metamorphism from this domain. Geochronological data thus tightly bracket the collisional orogeny in the CITZ at between 1.06 Ga and 0.94 Ga. When combined with re- cent data from collisional belts further east of the CITZ, namely the Chhotanagpur Gneissic Complex and Shillong Plateau Gneissic Complex, a uniformity of Mesoproterozoic to Early Neoproterozoic events is evident, implying final amalgamation of the North and South Indian blocks at this time along a ~1500 km long orogenic belt. This means that two or more separate blocks were in existence at the time of incorporation within Rodinia, not a single block as suggested in most current models. © 2011 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. 1. Introduction Central to developing working models on the growth of the Great- er Indian Landmass, and its integration within the Rodinia supercon- tinent, is a comprehensive understanding of the timing of the tectonothermal events along the 1500 km long E-W to ENE-WSW trending orogenic domain, which stretches from the Central Indian Tectonic Zone (CITZ) in the west, through the composite Chhotanag- pur Gneissic Complex (CGC)–North Singhbhum Mobile Belt (NSMB) in the east, to the Shillong Plateau Gneissic Complex (SPGC) in the north-east of India (Fig. 1a). The importance of this orogenic domain originates from its unique position in the heart of Peninsular India, where the North and South Indian Cratonic Blocks (NIB and SIB, re- spectively) were amalgamated to produce the Greater Indian Land- mass (Fig. 1a). Whereas recent geochronological and metamorphic findings appear to suggest a commonality of magmatic and high- grade metamorphic events in the time periods of 1.65–1.5 Ga and 1.1 to 0.9 Ga along the length of this orogenic domain (Fig. 1b) (reviewed in Bhandari et al., 2011; Bhowmik et al., 2011), the real sig- nificance of these events in relation to crustal amalgamation is debatable. Early tectonic models predicted southerly subduction of the NIB below the SIB between 2.1 and 1.8 Ga, leading to the suturing of the Gondwana Research 22 (2012) 54–72 ⁎ Corresponding author. Tel.: + 91 3222 283390. E-mail address: santanu@gg.iitkgp.ernet.in (S.K. Bhowmik). 1 Present address: Department of Geology, University of Delhi, Delhi-110007, India. 1342-937X/$ – see front matter © 2011 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.gr.2011.09.008 Contents lists available at SciVerse ScienceDirect Gondwana Research journal homepage: www.elsevier.com/locate/gr