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Comparative Stratigraphic and Geochronological Evolution of The Document generated on 09/26/2021 8:58 a.m. Geoscience Canada Comparative Stratigraphic and Geochronological Evolution of the Northern Damara Supergroup in Namibia and the Katanga Supergroup in the Lufilian Arc of Central Africa R. McG. Miller Volume 40, Number 2, 2013 Article abstract The Damara Supergroup in Namibia and the Katanga Supergroup in the URI: https://id.erudit.org/iderudit/geocan40_2pfh02 Central African Copperbelt (some 1000 km apart) are characterized by rock successions indicative of almost coeval orogenic evolution through phases of See table of contents intracontinental rifting, spreading, continental rupture, subduction, ocean closure and continental collision in what appears to have been a single, elongate orogenic belt. Rifting began at about 880 Ma and lasted until about Publisher(s) 800 or 756 Ma. Post-rift thermal sag and marine transgression produced the first correlatable stratigraphic units, the argillaceous Beesvlakte and Ore Shale The Geological Association of Canada Formations, in northern, carbonate-dominated platformal successions on the Damaran Northern Platform and the Katangan Lufilian Arc or Fold Belt, ISSN respectively. Sturtian (~735 Ma) and Marinoan (635 Ma) glacial units are common to both successions as well as syntectonic molasse sequences 0315-0941 (print) (~595–550 Ma). Continental collision occurred at about 542 Ma and the 1911-4850 (digital) post-tectonic peak of regional meta-morphism was at about 535–530 Ma. Mineral ages record cooling to about 460 Ma. The extensive occurrence of Explore this journal stratabound, but not stratiform, copper mineralization, evaporitic minerals, salt and thrust tectonics, syntectonic breccias, and intense alteration in the Lufilian Arc have no significant equivalents in the Northern Platform. Cite this article However, the Beesvlakte Formation has both concordant and strongly discordant styles of copper mineralization and the mode of occurrence of Miller, R. M. (2013). Comparative Stratigraphic and Geochronological Evolution mineralization in the Copperbelt can be a guide to exploration in Namibia. of the Northern Damara Supergroup in Namibia and the Katanga Supergroup in the Lufilian Arc of Central Africa. Geoscience Canada, 40(2), 118–140. All rights reserved © The Geological Association of Canada, 2013 This document is protected by copyright law. Use of the services of Érudit (including reproduction) is subject to its terms and conditions, which can be viewed online. https://apropos.erudit.org/en/users/policy-on-use/ This article is disseminated and preserved by Érudit. Érudit is a non-profit inter-university consortium of the Université de Montréal, Université Laval, and the Université du Québec à Montréal. Its mission is to promote and disseminate research. https://www.erudit.org/en/ 118 PAUL F. HOFFMAN SERIES the first correlatable stratigraphic units, débutée il y a environ 880 Ma et s’est the argillaceous Beesvlakte and Ore prolongé jusqu’à 800 Ma ou 756 Ma. Shale Formations, in northern, carbon- Le fléchissement thermique post-dis- ate-dominated platformal successions tension et la transgression marine ont on the Damaran Northern Platform donné les premières unités strati- and the Katangan Lufilian Arc or Fold graphiques corrélables, soit la Forma- Belt, respectively. Sturtian (~735 Ma) tion argileuse de Beesvlakte et la For- and Marinoan (635 Ma) glacial units mation de Ore Shale, de la portion are common to both successions as nord des successions de plateforme well as syntectonic molasse sequences principalement carbonatées sur la (~595–550 Ma). Continental collision Plateforme nord de Damaran et de Comparative Stratigraphic occurred at about 542 Ma and the l’Arc ou de la bande plissée de Katan- post-tectonic peak of regional meta- gan Lufilian respectivement. Les and Geochronological morphism was at about 535–530 Ma. unités glaciaires de Sturtian (~735 Ma) Evolution of the Northern Mineral ages record cooling to about et de Marinoan (635 Ma) sont com- 460 Ma. The extensive occurrence of munes aux deux successions, tout Damara Supergroup in stratabound, but not stratiform, copper comme les séquences de molasses syn- Namibia and the Katanga mineralization, evaporitic minerals, salt tectoniques (~595–550 Ma). La colli- and thrust tectonics, syntectonic brec- sion continentale s’est produite il y a Supergroup in the Lufilian cias, and intense alteration in the Lufil- environ 542 Ma et le pic post-tec- Arc of Central Africa ian Arc have no significant equivalents tonique de métamorphisme régional a in the Northern Platform. However, eu lieu il y a environ 535 à 530 Ma. R. McG. Miller the Beesvlakte Formation has both Selon les datations minérales, le refroidissement s’est produit il y a envi- Consulting Geologist concordant and strongly discordant ron 460 Ma. La prépondérance du PO Box 11222 styles of copper mineralization and the contexte stratoïde plutôt que strati- mode of occurrence of mineralization Windhoek, Namibia forme des minéralisations de cuivre, E-mail: [email protected] in the Copperbelt can be a guide to des minéraux d’évaporites, de sel et de exploration in Namibia. tectonique de compression, de brèches SUMMARY syntectoniques, et d’altération intense SOMMAIRE The Damara Supergroup in Namibia dans l’Arc de Lufilian, n’a pas d’équiva- and the Katanga Supergroup in the Le Supergroupe de Damara en Nami- lent dans la plateforme du nord. Central African Copperbelt (some bie et le Supergroupe de Katanga de la Cependant, la Formation de Beesvlakte 1000 km apart) are characterized by bande cuprifère d’Afrique centrale (dis- présente des minéralisations de cuivre rock successions indicative of almost tant de 1 000 km) sont caractérisés par qui sont ou concordantes, ou forte- coeval orogenic evolution through des successions de roches montrant ment discordantes, et le mode d’occur- phases of intracontinental rifting, une évolution orogénique presque con- rence de la minéralisation dans le spreading, continental rupture, subduc- temporaines dans leurs phases de dis- bande cuprifère peut servir de guide à tion, ocean closure and continental col- tension intracontinentale, d’expansion, l’exploration en Namibie. lision in what appears to have been a de rupture continentale, de subduction, single, elongate orogenic belt. Rifting de fermeture océanique et de collision INTRODUCTION began at about 880 Ma and lasted until continentale, dans ce qui semble avoir A correlation of the Damara Super- about 800 or 756 Ma. Post-rift thermal été une seule et même bande group of Namibia, particularly the sag and marine transgression produced orogénique étroite. La distension a Otavi Group of the Northern Plat- Geoscience Canada, v. 40, http://dx.doi.org/10.12789/geocanj.2013.40.007 © 2013 GAC/AGC® GEOSCIENCE CANADA Volume 40 2013 119 form of the Damara Orogen, with the Katanga Supergroup of the Lufilian Arc or Fold Belt in Zambia and the Democratic Republic of Congo (DRC) (Figs. 1, 2), i.e. the Central African Copperbelt, has long been accepted on the basis of broadly similar rock types, platform-like tectonic settings and geochronological data (Haughton 1963; Cahen and Snelling 1966; Cahen et al. 1984). The two regions underwent approximately coeval phases of rifting, ocean opening and closure, subduction and continental collision. Recent geochronological data are worth inves- tigating further in order to tighten this correlation and to highlight the poten- tial for Copperbelt-type mineralization in Namibia and for Damaran-type lead-zinc mineralization in the Katanga Supergroup. The recognition of two ‘Snowball Earth’ glacial units, the Chuos and Ghaub Formations (~735 Ma and 635 Ma, respectively), in the Damara Supergroup (Hoffmann and Prave 1996; Hoffman et al. 1998a) enable a direct correlation with the Grand and Petit Conglomérat of the Katanga Supergroup (Master and Wen- dorff 2011) to be made. The individual cap carbonates are similar: grey and Figure 1. Relative locations of the Pan-African Damara Orogen and Lufilian Fold laminated above the Chuos Formation Belt in southern Africa (modified after Miller and Schalk 1980; Kampunzu and and Grand Conglomérat, and tan or Cailteux 1999; Porada and Berhorst 2000). pink above the Ghaub Formation and Petit Conglomérat. Dates for many struction of detailed stratigraphic sec- trending Kaoko Belt (Guj 1970; stages in the evolutionary history of tions but they do document a near Goscombe et al. 2003a, b; 2005a, b; these two regions are almost identical. continuous extent of Damaran/Katan- Miller 2008; Miller et al. 2009a, b) and This paper briefly compares gan geology across the 1000 km ‘gap’ its southern equivalent, the Gariep Belt the lithostratigraphy (Table 1) and the between the main exposures in Namib- (Frimmel 2008). The evolutionary rela- chronology of sedimentary, structural ia and DRC/Zambia. tionships of these three belts to each and metamorphic evolution (Tables 2- other are comprehensively covered by 5) in these two major regional succes- GENERAL STRATIGRAPHY AND Frimmel and Miller (2009a, b), Frim- sions. Supporting information is STRUCTURE mel et al. (2009), Germs et al. (2009), gleaned from the adjoining Kaoko, Miller and Frimmel (2009), Miller et al. central Damara, and Zambezi Belts, all Damara Orogen (2009a, b) and Will et al. (2009). The of which evolved coevally with their Namibia’s Damara Orogen, consisting Damara and Kaoko Belts are divided corresponding platform facies. A few of three arms meeting at a triple junc- into contrasting tectonostratigraphic relevant dates from the
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