doi:10.1016/j.earscirev.2005.02.004
Copyright © 2005 Elsevier B.V. All rights reserved.
Amalgamating eastern Gondwana: The evolution of the Circum-Indian Orogens
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Alan S. Collinsa, 
, 
and Sergei A. Pisarevskyb
aContinental Evolution Research Group and Tectonics SRC, Geology and Geophysics, School of Earth and Environmental Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
bTectonics SRC, School of Earth and Geographic Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6907, Australia
Received 14 September 2004;
accepted 15 February 2005.
Available online 24 March 2005.
Abstract
The Neoproterozoic global reorganisation that saw the demise of Rodinia and the amalgamation of Gondwana took place during an incredibly dynamic period of Earth evolution. To better understand the palaeogeography of these times, and hence help quantify the interrelations between tectonics and other Earth systems, we here integrate Neoproterozoic palaeomagnetic solutions from the various blocks that made up eastern Gondwana, with the large amount of recent geological data available from the orogenic belts that formed as eastern Gondwana amalgamated. From this study, we have: (1) identified large regions of pre-Neoproterozoic crust within late Neoproterozoic/Cambrian orogenic belts that significantly modify the geometry and number of continental blocks present in the Neoproterozoic world; (2) suggested that one of these blocks, Azania, which consists of Archaean and Palaeoproterozoic crust within the East African Orogen of Madagascar, Somalia, Ethiopia and Arabia, collided with the Congo/Tanzania/Bangweulu Block at 
650–630 Ma to form the East African Orogeny; (3) postulated that India did not amalgamate with any of the Gondwana blocks until the latest Neoproterozoic/Cambrian forming the Kuunga Orogeny between it and Australia/Mawson and coeval orogenesis between India and the previously amalgamated Congo/Tanzania/Bangweulu–Azania Block (we suggest the name ‘Malagasy Orogeny’ for this event); and, (4) produced a palaeomagnetically and geologically permissive model for Neoproterozoic palaeogeography between 750 and 530 Ma, from the detritus of Rodinia to an amalgamated Gondwana.
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Fig. 1. Geological outcrop map of south, central and northeast Africa, India, East Antarctica and Australia (based on the data sets of IGCP 288, Wolmarans, 1999) rotated into the Gondwana fit of Reeves and De Wit (2000). Precambrian outcrops older than 1000 Ma shown as dark grey, those younger than 1000 Ma shown as light grey. Outlines of the Neoproterozoic continental blocks discussed in this paper and used in Fig. 2, Fig. 3, Fig. 4, Fig. 5 and Fig. 6 are marked in purple. Block abbreviations: A-A = Afif–Abas Terrane; Az = Azania; Congo = Congo/Tanzania/Bangweulu Block; L-V = Lurio–Vijayan Peninsula; R Plata = Rio de la Plata Block; Ruker = Ruker Terrane, Southern Prince Charles Mountains; S Fran = Sâo Francisco Block; WA = West African Block. Orogenic belt and location abbreviations: Alb-Fr = Albany–Fraser Orogen; ANS = Arabian–Nubian Shield; D Feliciano = Dom Feliciano Belt; Cam = Cameroon; L = Leeuwin Complex; M = Mulingarra Complex; MB = Mozambique Belt; N = Northampton Complex; Of = Officer Basin, Sey = Seychelles.
Fig. 2. Palaeogeographic reconstruction at 750 Ma. Deep yellow = continental plates delineated from map, pale yellow = hypothesized extend of continental crust. Amazon = Amazonia; Aus-Maw = Australia/Mawson Block; Az = Azania; Congo = Congo/Tanzania/Bangweulu Block; Kal = Kalahari Block; Laur = Laurentia; RP = Rio de la Plata; SF = Sâo Francisco; WA = West Africa. Adola, Adamastor, Braziliano, Mozambique, Pacific = oceanic basins. A polar 30° latitudinal circle is presented with relevant palaeomagnetic solutions rotated into congruence with the reconstruction—see Table 1 for details and Table 2 for rotation parameters. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 3. Palaeogeographic reconstruction at 630 Ma—key and abbreviations the same as for Fig. 2, except: Sah = Sahara Metacraton.
Fig. 4. Palaeogeographic reconstruction at 570 Ma with Laurentia in a high latitudinal position. Key and abbreviations the same as for Fig. 2 and Fig. 3.
Fig. 5. Palaeogeographic reconstruction at 570 Ma with Laurentia in a low-latitudinal position—key and abbreviations the same as for Fig. 2, Fig. 3 and Fig. 4.
Fig. 6. Palaeogeographic reconstruction at 530 Ma with an assembled Gondwana (present continental outlines reconstructed for Gondwana using the reconstruction of Reeves and De Wit, 2000)—key and abbreviations the same as for Fig. 2, Fig. 3 and Fig. 4, except: Ru = Ruker Terrane.
Fig. 7. Location and geological province map of India (geology based on, Commission for the Geological Map of the World, 2000). Bastar, Bundelkhand, Dharwar and Singhbhum = main Archaean cratons. Eastern Ghats = Eastern Ghats Orogen, EG = Eastern Ghats Province and K = Krishna Province of the Eastern Ghats Orogen, ChL = Chila Lake Domain of the Eastern Ghats Province (Dobmeier and Raith, 2003). A = Achancovil shear zone, B = Bhavani, CITZ = Central Indian Tectonic Zone, H = Highland Complex, KKPT = Karur–Kamban–Painavu–Trichur shear zone, M = Madurai Block, Meg = Assam and Meghalaya, P = Palani, PC = Palghat–Cauvery shear zone system, T = Trivandrum Block, V = Vijayan Complex, W = Wanni Complex.
Fig. 8. Location and geological province map of East Antarctica (geology based on Commission for the Geological Map of the World, 2000). The location of interpreted Neoproterozoic continental boundaries is drawn. DG-BH = Denman and Scott Glaciers and Bunger Hills, GM = Grove Mountains, KGV = King George V Land, PEL = Princess Elizabeth Land, QML = Queen Mary Land, RI—Rauer Islands and Terrane, SI = Søstrene Island, WI = Windmill Islands, Wilkes = Wilkes Land, VH = Vestfold Hills. Key as Fig. 7.
Fig. 9. Location and geological province map of East Africa, Arabia and Madagascar (geology based on Commission for the Geological Map of the World, 2000). AB = Al-Bayda Terrane, Abas = Abas Terrane, Al-M = Al-Mafid Block, An = Antongil Block, AR = Al-Rayn Terrane, Bem = Bemarivo Belt, Bs = Betsimisaraka Suture, HDR = Hulayfah–Ad Dafinah–Ruwah Suture, Buur = Buur Massif, CTB = Congo/Tanzania/Bangweulu Block, It = Itremo Group, KS = Keraf Suture, Lurio = Lurio Belt, Ma = Mait (or Maydh) Complex, Mo = Molo Group, QB-M = Qabri–Bahar and Mora Complexes, Rfz = Ruwah fault zone, Sahara = Saharan Metacraton, Rsz = Ranotsara shear zone, Yem = Yemen. Key as Fig. 7.
Fig. 10. Location and geological province map of central Africa (geology based on Commission for the Geological Map of the World, 2000). Bang = Bangweulu Block, CK = Choma–Kalomo Block, Congo–Angola–Kansai = Congo–Angola–Kasai Craton, CTB = Congo–Tanzania–Bangweulu Block, Damara = Damara Belt, Irumide = Irumide Belt, Kalahari = Kalahari Block, Kaoko = Kaoko Belt, Kibaran = Kibaran Belt, Oubanguides = Oubanguides Belt, Tanz = Tanzania Craton, Ub = Ubende belt, US = Usagaran Belt, W Congo = West Congo Belt, Zambezi = Zambezi Belt. Key as Fig. 7.
Fig. 11. Time–space plot for the middle to late Neoproterozoic tectonothermal events in orogens west, south and east of Gondwanan India.
Fig. 12. Location and geological province map of central Africa (geology based on Commission for the Geological Map of the World, 2000). Archaean–Palaeoproteroozic cratonic blocks, Amazonia, Luiz Alves, Rio de la Plata, São Francisco, São Luis (part of the West African Block). Proterozoic orogenic belts = Araçuai, Araguaia, Dom Feliciano, Borborema, Brazília, Paraguay, Ribeira. Geological provinces after Cordani et al. (2000). Key as Fig. 7.
Fig. 13. Schematic summary representation of the main Neoproterozoic continental blocks around India (Congo/Tanzania/Bangweulu, Azania, India and Australia/Mawson), the timing of closure of the Mozambique Ocean, the Mawson Sea and the unnamed ocean between Azania and the Congo/Tanzania/Bangweulu Block (dark grey blocks) and the intracontinental Molo basin between Azania and the Congo/Tanzania/Bangweulu Block (light grey block). Also shown are the orogenies that developed because of these collisions (the East African, Malagasy and Kuunga).
Table 1.
Neoproterozoic palaeomagnetic poles from Laurentian and Gondwanan blocks
750–530 Ma palaeomagnetic poles.
Quality factor (after Van der Voo, 1990).
a Rotated to India 28° counterclockwise around the pole of 25.8°N, 330°E (
Torsvik et al., 2001b).
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