March 2019 LIP of the Month

Precambrian Large Igneous Province record of the Indian Shield: an update based on extensive U-Pb dating of mafic dyke swarms

Amiya K. Samal¹, Rajesh K. Srivastava¹*, Richard E. Ernst^2,3, and Ulf Söderlund⁴

1 Centre of Advanced Study in Geology, Institute of Science, Banaras Hindu University, Varanasi 221005, India

2 Department of Earth Sciences, Carleton University, Ottawa, ON K1S5B6, Canada

3 Faculty of Geology and Geography, Tomsk State University,  Tomsk 634050, Russia

4 Department of Geology, Lund University, SE-223 62 Lund, Sweden

*corresponding author’s e-mail: rajeshgeolbhu@gmail.com

Extracted and updated from Samal, AK, Srivastava, RK, Ernst, RE and Söderlund, U. (2019) Neoarchean-Mesoproterozoic mafic dyke swarms of the Indian Shield mapped using Google Earth™ images and ArcGIS™, and links with Large Igneous Provinces. In: Srivastava, R.K., Ernst, R.E., Peng, P. (Eds.), Dyke Swarms of the World – A Modern Perspective, Springer Nature Singapore Pte Ltd., 335–390.

More details also available in:

Srivastava, R.K., Söderlund, U., Ernst, R.E., Mondal, S.K., Samal, A.K., 2018. Precambrian mafic dyke swarms in the Singhbhum craton, eastern India and their links with dyke swarms of the eastern Dharwar craton. Precamb. Res. (in press), https://doi.org/10.1016/j.precamres.2018.12.017.

Söderlund, U., Bleeker, W., Demirer, K., Srivastava, R.K., Hamilton, M.A., Nilsson, M., Pesonen, L., Samal, A.K., Jayananda, M., Ernst, R.E., Srinivas, M., 2018. Emplacement ages of Paleoproterozoic mafic dyke swarms in eastern Dharwar craton, India: implications for paleoreconstructions and evidence for a ~30° internal block rotation. Submitted to Precamb. Res. (in press), https://doi.org/10.1016/j.precamres.2018.12.017.

1. Introduction

Recognition of Large Igneous Provinces (LIPs) from shield area helps to provide significant information on ancient supercontinents (cf. Ernst, 2014). In general, a LIP comprises flood basalts, or their erosional/deformational remnants, a plumbing system of mafic dykes and sills, and also mafic-ultramafic layered intrusions. LIPs can also have close association with felsic magmatism (both intrusive and extrusive), carbonatites and in some cases lamprophyres, lamproites and kimberlites (Ernst and Buchan, 2001a,b; Ernst and Srivastava, 2008; Ernst et al., 2010, 2013, Ernst, 2014). It is now well established that mafic dyke swarmscan be the only easily recognized component of deeply eroded Proterozoic LIPs (e.g. Ernst and Buchan, 2001a,b; Bleeker Ernst, 2006; Ernst and Srivastava, 2008; Ernst and Bleeker, 2010; Meert et al., 2010; Ernst et al., 2010, 2013; Srivastava et al., 2010; 2019; Srivastava, 2011; Evans, 2013; Ernst, 2014). Mafic dyke swarms with an average width of > 10 m are considered diagnostic of membership in a LIP (Ernst, 2007, 2014). Therefore, LIPs can still be identified based on such dyke swarms, even in cases in which the LIP has been deeply eroded or fragmented by continental breakup such that the areal extent/inferred volume is less than the defined minimum of 100,000 sq. km/cu. km  (Coffin and Eldholm, 1994; Ernst, 2014). The Indian dyke swarms discussed in this article consist of dykes with an average width of more than 10 m and in many case up to 10s of meters, and are therefore considered to represent the plumbing system of LIPs.

The different Archean cratons of the Indian shield have an extensive record of early Precambrian (Neoarchean to Mesoproterozoic) mafic dyke swarms and many of these are thought to be parts of ancient LIPs (see Fig. 1: Murthy, 1987; Devaraju, 1995; Bleeker, 2003; Srivastava et al., 2008; Ernst and Srivastava, 2008; Heaman, 2008; Fench et al., 2008; French and Heaman, 2010; Pradhan et al., 2010; Srivastava, 2011; Ernst, 2014; Pivarunas et al., 2018; Shellnutt et al., 2018, 2019; Liao et al., 2019; Samal et al., 2019 and references therein). Samal et al. (2019) have presented comprehensive information on distinct Neoarchean to Mesoproterozoic mafic dyke swarms, mainly based on Google Earth™ images, field surveys, and published literature. Based on this work (Samal et al., 2019), we present an updated and modified information on these dyke swarms of the Indian shield.

Geological background

The geology of the Indian shield is described in several recent publications (cf. Naqvi and Rogers, 1987; Sharma, 2009; Ramakrishnan and Vaidyanadhan, 2010); however, a brief description is presented in this section. The Indian subcontinent, covering an area of approximately 5,000,000 km², is bordered by the Himalaya Mountains in the north, Indian Ocean in the south, Bay of Bengal in the east and Arabian Sea in the west. It is subdivided into Peninsular India in the south, the extra-Peninsular India in the north and the Indo-Gangetic Plain in between (Ramakrishnan and Vaidyanadhan, 2010). The Indian shield is a mosaic of Archean-Paleoproterozoic cratonic blocks and Meso- to Neoproterozoic mobile belts with Archean protoliths. It has attained its growth through nucleation, accretion and merging of three protocontinents viz., Dharwar, Aravalli and Singhbhum (Naqvi et al., 1974), which are further subdivided into seven cratons viz. Southern Granulite Terrain, Western Dharwar, Eastern Dharwar, Singhbhum, Bastar, Bundelkhand, and Aravalli (Naqvi et al., 1974, Naqvi and Rogers, 1987) (see Fig 1). The division of each craton is based on their characteristic features that distinguish it from other cratons. Many have suggested that most of the joins (tectonic boundaries) were active about 1500 Ma ago and discussed evidence for and against accretion (cf. Rogers, 1986; Naqvi and Rogers, 1987; Sharma, 2009; Ramakrishnan and Vaidyanadhan, 2010). A brief geological description of each Archean craton is described below.

The Dharwar craton is the largest Archean block of the Indian shield and has three sub-blocks i.e. eastern Dharwar craton (EDC), western Dharwar craton (WDC), and Northern Granulite Terrain (high-grade crustal block) in the southern part (Naqvi and Rogers, 1987; Santosh et al., 2009; Clark et al., 2009; Sharma, 2009; Ramakrishnan and Vaidyanadhan, 2010). The major E-W trending Palghat-Cauvery shear zone (PCSZ) separates the Southern Granulite Terrain (SGT; also known as the Pandyan Mobile Belt) from the Northern Granulite Terrain (NGT), whereas the Chitradurga fault, which exists along the eastern boundary of the Chitradurga greenstone belt, separates the EDC and the WDC. It is considered that the EDC, the WDC and the high-grade crustal block in the southern part share a common magmatic activity during the Proterozoic, particularly Paleoproterozoic mafic dykes (cf. Murthy, 1987; Ernst and Srivastava, 2008; Srivastava et al., 2008; Srivastava, 2011; Dash et al., 2013); therefore, the mafic dyke swarms emplaced in these three regions are discussed together.

The Bastar craton is bounded by Godavari rift in the SW, Mahanadi rift in the NE, Narmada-Son fault zone (Deccan Traps age rift system) in the NW, and Eastern Ghat Mobile Belt (EGMB) in the SE; and also Deccan Traps LIP in the west. The craton comprises granitoids of different generations, including 3.5-3.6 Ga TTG basement gneisses and ~2.5 Ga un-deformed and un-metamorphosed granites, supracrustal rocks, and a number of intracratonic Proterozoic sedimentary basins (cf. Naqvi and Rogers, 1987; French et al., 2008; Srivastava and Gautam, 2015; Ramakrishnan and Vaidyanadhan, 2010 and references therein). Mafic dykes of different generations are well preserved in the Bastar craton and mostly intruded within the Archean granitoids and supracrustals (cf. Ramachandra et al., 1995; Srivastava and Gautam, 2015; Samal et al., 2019 and references therein).

The Singhbhum craton consists of two major geological domains viz. the Singhbhum Granite Complex (SGC) and the Chotanagpur Gneissic Complex (CGC), separated by the Singhbhum Mobile Belt (SMB) (cf. Naqvi and Rogers, 1987; Sharma, 2009; Srivastava et al., 2009a, 2012, 2014a). Several generations of mafic dykes, ranging in age from Neoarchean to Paleoproterozoic, are well preserved in the SGC (Srivastava et al., 2018), however only few Mesoproterozoic mafic dykes are reported from the CGC (Srivastava et al., 2012).  The SGC comprises (i) two pulses of granitoid suites at 3.45–3.44 and 3.35–3.32 Ga, (ii) tonalities and trondhjemites of the Older Metamorphic Tonalitic Gneisses (OMTG) together with the Singhbhum granites at 3.45–3.44 Ga, and (iii) the OMTG, with slightly younger phases (~3.35–3.32 Ga) of Singhbhum granite (Upadhyay et al., 2014; Nelson et al., 2014; Dey et al., 2017). An early phase of relatively high-grade metamorphism at 3.30–3.28 Ga followed by extensive fluid-induced alteration during low-grade metamorphism at 3.19–3.12 and 3.02–2.96 Ga has also been described. Episodic Archean plume-related mafic-ultramafic (basaltic and komatiitic) magmatic underplating and intraplating in an oceanic plateau setting are also recorded (Sharma et al., 1994; Chaudhuri et al., 2015; Dey et al., 2017).

The Bundelkhand craton is separated from the Satpura mobile belt in the south and Aravalli craton in the west by the Proterozoic Vindhyan basin and consist of three distinct litho-tectonic units: (i) an Archean enclave suite with highly deformed older gneisses–greenstone rocks, (ii) a granite suite with undeformed multiphase granitoid plutons and associated quartz reefs, and (iii) an intrusive suite with mafic dykes and other intrusions (Sharma and Rahman, 2000; Meert et al., 2010). Paleoproterozoic NE–SW to NNE-SSW trending quartz veins/reefs show a spectacular distribution throughout the craton (Pati et al., 2007). Proterozoic rift basins also exist at the northern and southern peripheries of the Bundelkhand craton (Chakroborty et al., 2016). Mafic dykes with trends of NW–SE, ENE–WSW and NE–SW, crosscut all lithologies, and are well exposed (cf. Mallikarjhuna Rao, 2004; Pati et al., 2008; Pradhan et al., 2012; Ernst, 2014).

The Aravalli craton comprises six tectono-stratigraphic units viz. 1) Neoarchean (Cryogenian) Erinpura granites (Heron, 1953; Ramakrishnan and Vaidyanadhan, 2010), 2) Mesoarchean Mewar gneissic complex, 3) Neoarchean Mangalwar complex with Bhilwara group, 4) Paleoproterozoic Hindoli group and Aravalli supergroup along with mineralized supracrustal belts, 5) Mesoproterozoic Delhi supergroup and 6) Neoproterozoic Marwar supergroup, 750 Ma Malani igneous suite (part of a Silicic LIP; e.g. Ernst, 2014). The absence of greenstone belts and very limited occurrence of mafic dykes in any of the lithological units demarcates the uniqueness of the Aravalli craton with respect to other cratons of the Indian shield.

Early Precambrian LIP records of the Indian shield

Samal et al. (2019) have used several criteria, particularly available geochronology (see Table 1), and trends of dykes (Figs. 1 to 4), for grouping dykes into different swarms and, by inference, identification of different LIPs throughout the early Precambrian (the period between ~2.8 Ga and ~1.1 Ga) in the Indian shield. Locations of dated dykes are marked on Figures 2 to 4 (see serial numbers mentioned in Table 1 and marked on these figures). This exercise helped to identify eleven LIP events (see Table 2). The subsequent sections will provide brief descriptions of all the identified eleven LIPs of the Indian shield. Full details are available in Samal et al. (2019).

(1) ~2.75-2.80 Ga LIP(s)

This LIP is largely represented by the precisely dated ~2.80 Ga Keshargaria and ~2.75-2.76 Ga Ghatgaon swarms from the SGC (Kumar et al., 2017; see Fig. 4). Poorly dated/estimated ~2.70 Ga Sukma swarm (earlier identified as Keshkal swarm by Samal et al., 2019) of the Bastar carton (Srivastava et al., 2009b) and ~2.80 Jagat swarm of the Aravalli craton (Gopalan et al., 1990) are also thought to be part of this LIP. Mafic dykes of the ~2.80 Ga Keshargaria swarm trend NE-SW and are exposed in the northern part of the SGC, particularly around the Keshargaria region, whereas the NNE-SSW to NE-SW trending ~2.75-2.76 Ga Ghatgaon swarm is widely distributed throughout the SGC.

Other major dyke swarms of this LIP, exposed within the southern part of the Bastar craton, were identified as the Keshkal swarm by Samal et al. (2019), however new U-Pb ages (Shellnutt et al., 2018; Liao et al., 2019) suggest that the Keshkal region does not have dykes belonging to this LIP event. Instead this region has dykes belonging to the ~2.37 Ga Bhanupratappur swarm and/or ~1.88 Ga Bastanar swarm, the Keshkal swarm is re-named herein as the Sukma swarm since NW-SE trending ~2.7 Ga dykes are well exposed around this area (Srivastava et al., 2009b) (see Fig. 3). No other prominent dyke swarm is reported from any other part of the Indian shield to match these ages, however a poorly dated ~2.80 Ga Jagat swarm from the Aravalli craton is predicted to be part of this LIP.

(2)  ~2.36-2.50 Ga LIP(s)

This major LIP of the Indian shield are represented by the NE-SW to ESE-WNW trending ~2.36-2.37 Ga Bangalore-Karimnagar swarm of the Dharwar craton (Halls et al., 2007; French and Heaman, 2010; Kumar et al., 2012; Pivarunas et al., 2018; Söderlund et al., 2018; see Fig. 2) and the NW-SE trending ~2.37 Ga Bhanupratappur swarm of the Bastar craton (Liao et al., 2019) (see Fig. 3). The NE-SW trending ~2.36-2.37 Ga Bangalore-Karimnagar swarm is mostly exposed in the northern part of the EDC, whereas E-W, ENE-WSW, and ESE-WNW-trending dykes of this swarm are mostly encountered in the southern part of the EDC and also interpreted to extend into the WDC. The recently dated NW-SE trending ~2.37 Ga Bhanupratappur swarm of the Bastar craton (Liao et al., 2019) is well exposed in and around the Bhanupratappur and Keshkal regions. Another mafic dyke swarm with similar trend (NW-SE to WNW-ESE) is also reported from the southern part of the Bastar craton, identified as the Dantewara swarm (Samal et al., 2019) and has boninitic geochemical signatures (Srivastava et al., 2011a). No dyke of the Dantewara swarm is dated precisely; however based on field relationships, metamorphic ages, and the global distribution of boninite-norite magmatism, Srivasatava et al. (2011a) have suggested an emplacement age around 2.4–2.5 Ga. Some ENE–WSW trending mafic dykes that are mainly exposed around Dongargarh, Chhura, Lakhna and Bandalimal areas are also supposed to be part the Dantewara swarm (Samal et al., 2019).

(3) ~2.25-2.26 Ga LIP

This LIP event comprises the N-S to NNE-SSW trending ~2.25-2.26 Ga Ippaguda-Dhiburahalli swarm of the Dharwar craton (Nagaraju et al., 2018a; Söderlund et al., 2018; see Fig. 2) and the NE-SW to ENE-WSW trending ~2.26 Ga Kaptipada swarm of the SGC (Srivastava et al., 2018; see Fig. 4). The Ippaguda-Dhiburahalli swarm of the Dharwar craton is exposed only in the EDC, with N-S dykes in the northern part and NNE-SSW dykes exposed in the southern part (Söderlund et al., 2018). Dykes of this swarm are not reported from other parts of the Dharwar craton. Mafic dykes of similar age (~2.26 Ga), which trend in NE-SW to ENE-WSW are also known from the SGC and identified as the Kaptipada swarm (Srivastava et al., 2018). This swarm is distributed throughout the SGC, particularly in and around Kaptipada, Bhagamunda, and Ghatgaon regions. Based on the presence of these matching ~2.25-2.26 Ga dyke swarm intrusions in the Dharwar and Singhbhum cratons, Srivastava et al. (2018) has envisaged that the intervening Bastar craton must also host ~2.25-2.26 Ga dykes.

(4) ~2.21-2.22 Ga LIP

This LIP is restricted to the Dharwar craton only and is represented by mafic dykes of two sub swarms – (i) the N-S to NNW-SSE trending ~2.22 Ga Kandlamadugu sub-swarm (French and Heaman, 2010; Srivastava et al., 2011b, 2014b; Kumar et al., 2014; Nagaraju et al., 2018b; Söderlund et al., 2018) and (ii) the NW-SE to WNW-ESE trending ~2.21 Ga Anantapur-Kunigal swarm (cf. French and Heaman, 2010; Nagaraju et al., 2018a; Söderlund et al., 2018; see Fig. 2). Mafic dykes of the Kandlamadugu swarm mainly exposed in the EDC; however some N-S dykes in the WDC are also thought to belong to this swarm. This swarm also includes a >500 km long N-S trending dyke (which swing to NNW-SSE trending in the northern portion) running parallel to the Closepet granite (Söderlund et al., 2018). En échelon segments of this dyke can be seen from Google™ Earth images that may indicate intrusion of several, parallel- to near-parallel, dykes. On the other hand, mafic dykes of the Anantapur-Kunigal swarm are distributed across the entire Dharwar craton (including the EDC, WDC and NGT regions; see Fig. 2); the southern part is dominated by NW-SE trending dykes, whereas in the northern part they trend WNW-ESE to E-W (Samal et al., 2019).

(5) ~ 2.18 Ga LIP

This LIP is also mainly represented by mafic dykes exposed in the Dharwar craton and no other mafic dykes of this age are known from any other cratons of the Indian shield except the poorly dated ~2.18 Ga Bijli rhyolite flows exposed in the Bastar craton. A number of ~2.18 Ga mafic dykes are well exposed in the Dharwar craton and identified as the Mahbubnagar-Dandeli swarm (French and Heaman, 2010). Most of the dykes of this swarm trend NW-SE to WNW–ESE, with a few trending in NNW-SSE (see Fig. 2).

(6) ~2.08 LIP

This is represented by a radiating ~2.18 Ga Devarabanda dyke swarm mainly exposed along western curved margin of the Cuddapah basin but not intruding the basin (see Fig. 2; Demirer 2012; Kumar et al., 2015; Söderlund et al. 2018). They trend N-S to NNW-SSE in the northern EDC, NW-SE in the middle portion of the EDC (particularly around Devarabanda), and NE-SW to ENE-WSW in southern part of the EDC and also probably extending into the WDC (Fig. 2). Dykes of this age not reported from any other Archean craton of the Indian shield; however a poorly dated ~2.10 Ga gabbro sill within the Gwalior basin of the Bundelkhand craton may be part of this event.

(7) ~1.98 Ga LIP

The ~1.98 Ga intrusions are reported from the Bundelkhand craton only and no other craton of the Indian shield has any magmatism of this age. This LIP is mainly represented by NW-SE trending ~1.98 Ga mafic dykes of the Jhansi swarm (Pradhan et al., 2012; Ernst, 2014), which are widely distributed in the craton (Fig. 1), particularly around Khajuraho, Lalitpur, Babina, Jhansi and Karera areas. A poorly dated ~1.98 Ga gabbro sill, intruded within the Bijawar basin (at the southern tip of the Bundelkhand craton) is probably part of this LIP.

(8) ~1.85-1.90 Ga LIP

This is probably the largest LIP known from the Indian shield, and it covers almost every part of the Indian shield (cf. French et al., 2008; Ernst and Srivastava, 2008; Belica et al. 2014; Srivastava and Samal, 2019; Shellnutt et al., 2018, 2019). This LIP is particularly well represented by a number of precisely dated mafic dykes and sills exposed in the Dharwar as well as the Bastar cratons. This includes the (i) E-W trending ~1.88-1.89 Ga Hampi swarm in the EDC and WDC (Chatterjee and Bhattachrjee, 2001; Halls et al., 2007), (ii) ~1.88-1.89 Ga Pulivendla sills in the Cuddapah basin (Anand et al., 2003; French et al., 2008), (iii) NW-SE trending ~1.85 Ga Dharmapuri swarm in the EDC, WDC and NGT (Radhakrishna et al., 1999; Belica et al., 2014), (iv) NW-SE trending ~1.88-1.89 Ga Bastanar swarm in the Bastar craton (French et al., 2008; Shellnutt et al., 2018), and (v) NNW-SSE trending ~1.85 Ga Sonakhan swarm in the Bastar craton (Shellnutt et al, 2019) (see Figs. 2 & 3). All the subunits of ~1.85-1.89 Ga mafic magmatism suggest their convergence point towards the eastern side of the Dharwar craton, marking the location of its mantle plume centre (French et al., 2008, Ernst and Srivastava, 2008; Belica et al. 2014; Shellnut et al. 2018). Two felsic tuff samples, collected from the upper part of the Tadpatri formation of the Cuddapah basin, yield SHRIMP U-Pb zircon ages of 1864±13 Ma and 1858±16 Ma, respectively (Sheppard et al., 2017), which could also be part of the ~1.85 Ga LIP event of the Dharwar craton. A number of poorly dated ~1.80-1.90 Ga mafic intrusive rocks within the Himalayan Mountain Range (Ahmad et al., 1999; Miller et al., 2000) are also thought to be part of this LIP (Srivastava and Samal, 2019).

(9) ~1.77-1.79 LIP

This is the youngest Paleoproterozpoic LIP event reported from the Indian shield and is represented by the ~1.79 Ga Pebbair swarm in the EDC (Söderlund et al., 2018) and the ~1.77 Ga Pipilia swarm in the SGC (Shankar et al., 2014; Srivastava et al., 2018). The ~1.79 Ga Pebbair swarm consists of NW-SE trending mafic dykes and has limited exposures; it is reported only in northern part of the EDC, particularly in and around Pebbair (see Fig. 2). On the other hand, the ~1.77 Ga WNW-ESE to NW-SE trending Pipilia swarm is well represented in the SGC, particularly in the southern part (see Fig. 4). Srivastava et al. (2018) have argued that the Bastar craton should also host this event. This assumption is based on the presence of ~1.77-1.79 Ga units in the Dharwar and Singhbhum cratons, which are on opposite sides of the Bastar craton.

(10) ~1.42-1.46 LIP

A Mesoproterozoic LIP event is observed in Bastar craton and is represented by two dyke swarms viz. (i) the ENE-WSW trending ~1.42 Ga Bandalimal swarm exposed within the eastern part of the Chattisgharh Proterozoic basin, NE part of the Bastar craton (Das et al., 2011) and the N-S trending ~1.44-1.46 Ga Lakhna swarm (with compositions of rhyolite, trachyte, alkali gabbro, and dolerite) mostly reported from the NE part of the Bastar craton (Ratre et al., 2010; Pisarevsky et al., 2013) (see Fig. 3). A few mafic dykes trending N-S to NNW-SSE are also recorded from the NW part of the Bastar craton and are thought to also be part of the Lakhna swarm (Samal et al., 2019). Mafic units of this age are not reported from any other craton except for the ~1.42 Ga lamproite dykes exposed around Chelima within the Cuddapah basin of the EDC (Chalapathi Rao et al., 1999).

(11) ~1.05-1.12 Ga LIP

This is the youngest known Precambrian LIP of the Indian shield and is represented by the ~1.11 Ga ENE-WSW trending Mahoba mafic dyke swarm of the Bundelkhand craton (Pradhan et al., 2012; Ernst, 2014). This LIP is accompanied by a number of occurrences of kimberlite and lamproite intrusions in the EDC,Bastar craton, and VindhyanProterzoic basin (Gregory et al., 2006; Chalapathi Rao et al., 2013; Sahu et al., 2013; Chalapathi Rao et al., 2016).

Possible global correlation

The Earth’s history is known for the episodic tectonic processes of assembly and breakup of continents, which are identified as the supercontinents/supercratons (Worsley et al., 1982, 1984; Li et al., 2008; Nance et al., 2014). Several such supercontinent/supercratons are identified and established during the Precambrian. These include Rodinia (1.20-0.72 Ga), Columbia/Nuna (1.80-1.38 Ga), Kenorland (Superia+Sclavia – 2.75-2.07 Ga), Vaalbara (3.10-2.80 Ga), and Ur (~3.0 Ga) (e.g. Rogers 1996; Bleeker, 2003; Rogers and Santosh 2003; Li et al., 2008; de Kock et al., 2009; Meert, 2012; Ernst et al., 2013; Evans, 2013; Smirnov et al., 2013; Pisarevsky et al., 2014; Nance et al., 2014). Rift-related mafic dyke swarms are one of best types of evidence to mark the breakup of supercontinents (Worsley et al., 1982, 1984; Windley, 1984; Condie, 1989). Ernst (2014) has also emphasized that every major Precambrian breakup and formation of a new ocean should be linked to a LIP (and its associated dyke swarms) based on the evidence from the Gondwana supercontinent breakup record (e.g. Storey, 1995).

            Table 3 presents possible correlations of identified LIPs from the Indian shield with their likelymatches from the other parts of the globe. See Samal et al. (2019), Srivastava et al. (2018) and Söderlund et al. (2018) for more details. LIPs can provide robust constraints on reconstructions of various Indian cratons within Precambrian supercontinents, through using both using the LIP barcode matching method (Ernst and Bleeker, 2006; Ernst et al., 2013) and paleomagnetic studies which rely greatly on mafic dyke swarms (e.g. Evans, 2013; Buchan, 2013; Pisarevsky et al., 2015). Possible internal bending within the Dharwar craton (between north and south parts) is suggested by a changing trend in certain dyke swarms (for more details see Söderlund et al. 2018).

Full characterization of the LIP records of the Indian cratons (both their dyke swarms and associated intrusions and volcanics) would help constrain the timing and pattern of assembly of the various Indian cratons and any post-assembly rotations between the various cratons. The LIP records can also be used in targeting for new metallogenic systems. It is now well established that LIPs can also provide significant input of energy and metals and thereby contribute to the genesis of various types of mineralization (Ernst and Jowitt, 2013, 2017).

Conclusions

This meticulous exercise helped to identify distinct 24 dyke swarms and 10 other intrusions, 15 mafic magmatic events, and 11 LIPs (see Tables 1 and 2) in the Indian shield in the Precambrian. All of these swarms/events represent the exposed plumbing system for large igneous provinces (LIPs). This expanded record of dated LIPs/dyke swarms from the Indian shield have been correlated with matching LIPs on other crustal blocks and clearly indicate that the Indian shield was an integral part of all the known supercontinents during Precambrian (Table 3). These data along with new paleomagnetic studies will provide robust constraints for the setting of the Indian cratons within these supercontinents.

Acknowledgements

This work is part of a number of projects sanctioned to RKS and he is thankfully acknowledged the Department of Science and Technology, Government of India, New Delhi (Research Scheme number SR/S4/ES-590/2011), the Ministry of Earth Sciences, Government of India, New Delhi (Research Scheme number MoES/16/10/11-RDEAS), and the Council of Scientific and Industrial Research, New Delhi (Research Scheme number 24 (0348)/17/EMR-II) for financial supports. REE was partially supported from Russian Mega-Grant 14.Y26.31.0012. RKS and AKS are also thankful to the Head of the Department of Geology, Banaras Hindu University, for access to all necessary facilities, which were developed with DST-PURSE grant (Scheme5050) and UGC-CAS Phase-II grant (Scheme 5055) during this work.