Downloaded from http://sp.lyellcollection.org/ by AJS on May 1, 2016 Metallogeny and its link to orogenic style during the Nuna supercontinent cycle SALLY J. PEHRSSON1*, BRUCE M. EGLINGTON2, DAVID A. D. EVANS3, DAVID HUSTON4 & STEVEN M. REDDY5 1Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, Canada K1A 0E8 2University of Saskatchwan, 114 Science Place, Saskatoon, Saskatchewan, Canada S7N 5E2 3Yale University, 210 Whitney Avenue, New Haven CT 06520–8109, USA 4Geoscience Australia, GPO Box 378 Canberra ACT 2601 Australia 5The Institute for Geoscience Research, Dept. of Applied Geology, Curtin University, GPO Box U1987, Perth WA6845, Australia *Corresponding author (e-mail: [email protected]) Abstract: The link between observed episodicity in ore deposit formation and preservation and the supercontinent cycle is well established, but this general framework has not, however, been able to explain a lack of deposits associated with some accretionary orogens during specific periods of Earth history. Here we show that there are intriguing correlations between styles of oro- genesis and specific mineral deposit types, in the context of the Nuna supercontinent cycle. Using animated global reconstructions of Nuna’s assembly and initial breakup, and integrating extensive databases of mineral deposits, stratigraphy, geochronology and palaeomagnetism we are able to assess spatial patterns of deposit formation and preservation. We find that lode gold, volcanic- hosted-massive-sulphide and nickel–copper deposits peak during closure of Nuna’s interior ocean but decline during subsequent peripheral orogenesis, suggesting that accretionary style is also important. Deposits such as intrusion-related gold, carbonate-hosted lead-zinc and unconfor- mity uranium deposits are associated with the post-assembly, peripheral orogenic phase. These observations imply that the use of plate reconstructions to assess orogenic style, although challen- ging for the Precambrian, can be a powerful tool for mineral exploration targeting. Supplementary material: Supplementary material including (1) tables (S1–S3) of Euler poles and palaeopoles used, summary of Nuna orogens; (2) a figure (S1) of modelled plate velocities; (3) mp4 files (S1 & S2) of the model with age data; ore deposits and VGPs; and (4) a zip file (S1) of the Gplates model is available at http://www.geolsoc.org.uk/SUP18822. Although Wegener (1912) successfully reconstruc- kinematic evolution are important first steps in a ted, to first order, the Pangaea supercontinent almost new approach to reconstruction (Evans & Mitchell exactly 100 years ago, attempts to reconstruct ear- 2011; Zhang et al. 2012). Further confidence lier, Precambrian landmasses are hampered by in reconstructions can be gained from integrating oceanic lithosphere subduction, poor biogeographic global stratigraphic and geochronological informa- control, crustal recycling and erosion and palaeo- tion (Eglington et al. 2009; Pisarevsky et al. 2014), magnetic overprinting. Neoproterozoic Rodinia has more routine usage of palaeomagnetic field stabil- begun to take form (Li et al. 2008), evolving in ity tests to demonstrate primary ages of remanence a manner that appears consistent with Pangaean (Buchan et al. 2000; Evans & Pisarevsky 2008) dynamics (Li & Zhong 2009). Palaeoproterozoic and innovative visualization software (Williams Nuna (also called Hudsonland or Columbia; Meert et al. 2012). 2012; Evans 2013) reconstructions have suffered The use of palaeogeographical reconstructions from inaccurate geometric rendering (Rogers & in metallogenic targeting and understanding ore Santosh 2002; Zhao et al. 2002), merely regional deposit controls has been hitherto limited for the palaeomagnetic consideration (Bispo-Santos et al. Precambrian because of the inherent geometric 2008; Hou et al. 2008) or lack of a coherent plate and kinematic uncertainty of most reconstruction kinematic evolution (Hoffman 1997; Meert 2002; models. The aforementioned advances in Nuna Pesonen et al. 2003; Payne et al. 2009). Recent models can now be viewed in the context of well- models that do incorporate geometric accuracy and established linkages between the supercontinent From:Li, Z. X., Evans,D.A.D.&Murphy, J. B. (eds) 2016. Supercontinent Cycles Through Earth History. Geological Society, London, Special Publications, 424, 83–94. First published online June 4, 2015, updated July 1, 2015, http://doi.org/10.1144/SP424.5 # 2016 Her Majesty the Queen in Right of Canada, as represented by the Minister of Natural Resources Canada. Published by The Geological Society of London. All rights reserved. For permissions: http://www.geolsoc.org.uk/permissions. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics Downloaded from http://sp.lyellcollection.org/ by AJS on May 1, 2016 84 S. J. PEHRSSON ET AL. cycle and secular changes in ore deposit patterns (Pisarevsky et al. 2014), faces greater difficulty in (Barley & Groves 1992; Goldfarb et al. 2009; evolving towards Rodinia (Evans 2013). Kalahari Cawood & Hawkesworth 2015) and specific deposit may have been a lone craton, and Cathaysia is typi- types recognized as associated with (a) continental cally placed in the Australian sector (Li et al. 2008). assembly, for example, lode gold (Goldfarb et al. Other cratons with differing locations in recent 2009), volcanic-hosted-massive sulphide (Huston models include North China and India, which vary et al. 2010) and carbonate-hosted lead–zinc (Leach from clustered to separate in various positions et al. 2010) or (b) continental breakup, e.g. iron- (Zhao et al. 2002; Bispo-Santos et al. 2008; Hou oxide–copper–gold (IOCG; Groves et al. 2010) et al. 2008; Evans & Mitchell 2011; Zhang et al. and sedimented-hosted copper (Hitzman et al. 2012). Our new model, utilizing PaleoGISTM and 2010). We present herein new intriguing obser- GPlates (Williams et al. 2012) software, is pre- vations about patterns of orogenesis and mineral sented as both an animation (see Supplementary deposit types, founded on the integration of exten- material) and as five time slices through the interval sive mineral deposit, geochronologic, stratigraphic 2.2–1.3 Ga (Figs 1–3), with known ore deposits and palaeomagnetic databases with a new animated, superimposed. For this contribution we compiled kinematically viable model for the assembly and more than 106 000 crystallization, metamorphism, breakup of Nuna. Our new model was developed and cooling, summary detrital and model ages and more visualized utilizing PaleoGISTM and GPlates (Wil- than 15 000 mineralization occurrences with deposit liams et al. 2012) software, and enables assessment types in the StratDB and Dateview databases (pub- of patterns of mineralization within the superconti- lically available online from http://sil.usask.ca/ nent cycle. Although we do not consider it to be databases.htm). Most deposit information was com- the last word on Nuna’s evolution, we present piled and modified from the World Mineral Deposit the approach as an example of how a more dyna- database of the Geological Survey of Canada. Par- mic process of reconstruction, robustly integrating ticular care was taken to integrate digital map-based multiple datasets, can bring about innovation. craton topologies, relative positions and conver- gence of cratons linked with orogenic history, and avoid overlap of cratons following convergence. TM Method and approach We created 678 plate polygons in ArcGIS based on digital geological and geophysical maps, Numerous reconstructions for an assembled Nuna, refined by information from the above databases founded on palaeomagnetic (Rogers & Santosh and the literature (Supplementary Document S1 2002; Evans & Mitchell 2011; Zhang et al. 2012) and Supplementary Model S1 in the Supplementary or geological (Bispo-Santos et al. 2008; Meert material). Deposit and geochronological point 2002; Pesonen et al. 2003) data, or their combi- locality information and attributes were linked to nation (Pisarevsky et al. 2014), show a remarkable the plates via a spatial join in ArcMapTM. overall conformity. The current generation of The model was developed using GPlates (http:// Nuna models is loosely connected to the eventual www.gplates.org), PaleoGIS (http://www.Paleo assembly of a standard Rodinia model (Li et al. gis.com) and custom-developed software, assuming 2008) with minimal intervening motion. Relative rigid plates throughout. Our continuous GPlatesTM placement of Laurentia with Baltica to its east model of Nuna evolution from 2.2 to 1.3 Ga is pre- (present coordinates) and Siberia to its north is sented in a series of time steps (Supplementary ani- common to all models, with minor variations in mations S1 and S2 and Supplementary Model S1 in tightness of the Siberia–Laurentia connection the Supplementary material) and is based on orogen (Pisarevsky et al. 2014). We follow recent recon- histories (Supplementary Table S1 and vergence, structions favouring a tighter fit (Evans & Mitchell geometry, viable plate velocities and palaeomag- 2011; Zhang et al. 2012). It is now standard to netic data, the latter a subset of highest-reliability show Laurentia–Australia–Antarctica in a proto- poles from a comprehensive and rigorous assess- SWEAT connection (Payne et al. 2009; Zhang ment of the global palaeomagnetic database (Sup- et al. 2012) with Australia adjacent to northwestern plementary Table S2). Validity of the model was Laurentia. Amazonia and West Africa are typically tested through comparison of virtual geomag- shown attached to Baltica