2.2 ARCHEAN AND MESOPROTEROZOIC BASEMENT IN THE LUFILIAN FOLD BELT

Transcription

1 15 Chapter 2 Regional and District Geology 2.1 INTRODUCTION This chapter outlines the geodynamic history of southern and central Africa and the regional and deposit scale geology at NKM. The chapter focuses on orogenesis and crustal growth, basin formation, deformation and intrusives events during the late Proterozoic to early Palaeozoic period. District scale stratigraphic and structural relationships are discussed using previously published data and unpublished historical data. The distribution of copper and cobalt across the region suggests that significant regionally extensive basin and structural controls were important during the mineralisation process. The Neoproterozoic to earliest Phanerzoic Lufilian Fold Belt (LFB) is host to the Zambian and Congolese Copperbelts (ZCB and CCB). The LFB forms part of a series of linked Pan-African orogenic belts fringing the Congo and Kaapvaal-Zimbabwe cratons of southern Africa (Fig. 2.1a) (Porada, 1989; Porada and Berhorst, 2000; Selley et al., 2005). The tectonic evolution of southern Africa has been the focus of numerous studies (e.g. Bateman, 1930; Miller, 1983; Cahen et al., 1984; Daly et al., 1984; Daly, 1986; Cosi et al., 1992; Porada and Berhorst, 2000; Hanson, 2003; Johnson et al., 2005; Selley et al., 2005). The interpretation of the tectonic evolution is still controversial, however during the past decade advances in geochronology and field based studies have provided important new information (e.g. Porada and Berhorst, 2000; Hanson, 2003; Johnson et al., 2005). A comprehensive discussion of this research is beyond the scope of this study and readers are directed to the reviews of Porada and Berhorst (2000), Hanson (2003), Johnson et al., (2005) and Selley et al.,(2005). The Neoproterozoic sedimentary and volcanic sequences that form the supra-crustal component of the fold belts record a history of crustal extension, subsidence and intraplate magmatism between 1000 and 600 Ma that are conventionally interpreted to relate to the dispersal of the Rodinia Supercontinent ( Wilson et al., 1997; Porada and Berhorst, 2000). The term Pan-African herein will only be used for the Palaeozoic collisional event forming Gondwana and the post-orogenic magmatism, shearing and uplift. 2.2 ARCHEAN AND MESOPROTEROZOIC BASEMENT IN THE LUFILIAN FOLD BELT The regional geology of southern Africa is subdivided into three main Proterozoic orogenic mobile belts which enclose Archean and Palaeoproterozoic crustal fragments. The development of these belts was controlled by six Archean cratonic nuclei: the Kaapvaal, Zimbabwe, Tanzania, Bangweulu, Congo and Angola-Kasai Cratons (Fig. 2.1). These stable fragments form the core of the tectonic assemblage in southern Africa and include Archean fragments which were amalgamated with Palaeo- and Mesoproterozoic fragments to form two stable

2 16 (A) West Congo Belt Damara Belt Lufilian Fold Belt Congo Craton Zambezi Belt Kalahari Craton Gariep Belt fold belt Fig 2.1(B). Mozambique Belt Mwembeshi Shear Zone 1000KM foreland basin (B) Lufilian Fold Belt Ga felsic province Ga mafic province Foreland basin Fig 2.4. External Fold and Thrust Belt A Domes Region Synclinorial Belt Katanga High Zambezi Belt Basement Ga orogen Ga orogen Archaean shield Central African Copperbelt Copper deposit 25 0 ZAMBIA Mwembeshi Shear Zone DRC A Kibaran Belt ZCB CCB Bangweulu Block Fig 2.5. Irumide Belt Mozambique Belt Kalahari Craton ZIMBABWE 20KM Zambezi Belt 15 0 Figure 2.1. a). The crustal architecture of southern Africa. Simplified geology map of the Pan-African system of central and southern Africa. The Lufilian Fold Belt (LFB) is situated between the Congo and Zimbabwe-Kaapvaal Cratons to the north and south respectively. The LFB hosts the Zambian and Congloese Copperbelts (modified from Kampunzu and Cailteux, 1999; Porada and Berhorst, 2000). b). The tectonic zoning in the LFB (from Selley et al., 2005). The LFB is divided into four separate tectonic zones and the copper deposits are distributed mainly within the External Fold and Thrust Belt, the Domes region and the Synclinorial belt. Selley et al. (2005) included the basement inliers of the Zambian Copperbelt within the Domes Region, rather than the External Fold and Thrust Belt, as have previous subdivisions of the LFB (e.g. Kampunzu and Cailteux, 1999). blocks. In the north the Congo block includes the Angola-Kasai and the Tanzania cratons and the Bangweulu block, while in the south the Kalahari block includes the Zimbabwe and Kaapvaal cratons. The assembly of Archean and Paleoproterozoic cratons during the Mesoproterozoic (1300 to 1000 Ma) formed the Rodinia supercontinent (Hoffman, 1999; Rainaud et al., 2002). Archean rocks are not exposed in the LFB, however a ~3.1 Ga detrital zircon population in the Neoproterozoic supracrustal assemblage implies that Archean rocks either comprise part of basement or contributed material during Proterozoic evolution (Hanson, 2003). The oldest rocks (i.e. basement ) of the LFB consist of Palaeoproterozoic and volumetrically subordinate Mesoproterozoic meta-granites, migmatites, meta-volcanic and meta-sedimentary units (Hanson, 2003). They are predominantly exposed in the northwestern (Kibaran Belt) and south-eastern (Irumide Belt) peripheries of the LFB, and as smaller inliers between these areas, in a belt known as the Domes Region (Fig. 2.1). Basements rocks in the Domes region and Irumide Belt consist of two lithologies and temporal distinct assemblages. The oldest group of rocks known as the Lufbu Schist are widespread and part of metamorphosed Paleoproterozoic (~1994 to 1873Ma) magmatic arc sequence of sedimentary and volcanic rocks (Master et al., 2002; Mendelsohn, 1961). Unconformably overlying these rocks is the ~1300 to 1100 Ma Muva Group, a meta-sedimentary succession of conglomerates, orthoquartzites and meta-pelites (Rainaud et al., 2002). 2.3 NEOPROTEROZOIC EXTENSION The break-up of the Rodinia supercontinent occurred between ~1000 and 700 Ma (Miller, 1983; Munyanyiwa et al., 1997; Unrug, 1997). Rifting was extensive between the Kalahari and Congo cratons and formed a series

3 17 of eastward younging rift basins, now distinguished as separate orogenic belts including the Gariep, Damara, Zambezi, Lufilian and Mozambique belts (Hanson et al., 1993, 1994; Unrug, 1997). This sequence of metasedimentary and meta-volcanic rocks is known as the Katangan Supergroup. The supracrustal sequences of the Damara-Lufilian-Zambezi belts were previously amalgamated with the Brasiliano belt of South America (Hanson et al., 1993). The LFB is a record of intracontinental rift basins containing coarse-grained terrigenous and marine units. These were deposited within fluvial and alluvial fan environments and are overlain by carbonate and evaporitic strata, indicating a restricted marine or lacustrine environment with minor volcanic rocks (Porada and Berhorst, 2000; Selley et al., 2005). The relationships and architecture of the Neoproterozoic basins, originally deposited along the trend of Damara-Lufilian-Zambezi Orogen, are subjected to ongoing debate. The rifting history of the Zambezi belt is recorded by multiple magmatic phases spanning from ~880 to ~740 Ma (Hanson, 2003; Hargrove et al., 2003). At the western end of the rift trend line in the Damara Belt Miller (1983), Porada (1989) and Hanson (2003) suggest that the deposition of the marine sequence of carbonates and turbidites were synchronous with continental rift sedimentation in the east. The Damara Belt records a complete Late Proterozoic Wilson cycle from intracontinental rifting and the opening of oceanic basins, to the deposition of >10 km thick package of fluviatile to turbidite siliciclastics, carbonates and igneous rocks, through to collision and development of a foreland basin (Miller, 1983; Stanistreet et al. 1991; Munyanyiwa et al., 1997; Hoffman, 1999;). Volcanism accompanied extension in the Damara Belt, with the deposition of thick alkaline rhyolitic ignimbrite sequences along the northern rift margin. Continental tholeiitic and alkaline basalts were deposited higher in the sequence (Miller, 1983; Hanson, 2003). The eastern limit of the Damara belt is marked by a major transform fault inherited from pre-existing crustal weak zone, which separated the Damara and Katangan rift basins. Magmatism in the LFB is limited to sparse bimodal volcanic rocks and mafic to intermediate igneous bodies in the middle part of the Katangan Supergroup (Kampunzu et al., 2000). Basalts, pyroclastic and metagabbroic rocks are identified higher in the sequence and restricted to the western and northern sections of the LFB (Kampunzu et al., 2000; Key et al., 2001). Armstrong et al. (1999) reported a single U-Pb zircon age of 877 ± 11Ma for an extension-related A-type granite which intruded Palaeoproterozoic basement rocks in the ZCB prior to deposition of the Katangan Sequence (Kampunzu et al., 2000; Porada and Berhorst, 2000; Tembo et al., 2000; Hanson, 2003). Within the ZCB, gabbroic and dioritic intrusions predominate (Selley et al., 2005). The mafic and intermediate lavas and intrusive complexes in the western and central parts of the LFB are associated with a relatively short-lived magmatic event dated between ~765 and ~735 Ma (Key et al., 2001; Barron, 2003) (Fig. 2.3). The geochemical evolution of the mafic units ranges from earliest continental tholeiite, to alkaline and tholeiitic magmas, and finally to lavas with E-MORB affinities, suggest progressive continental rifting which resulted in an embryonic oceanic rift in the western LFB (Kampunzu et al., 2000). The northern border of rift basin was marked by a carbonate platform with a lagoonal basin developing to the south of the platform (Porada and Berhorst, 2000). Interestingly, there are significant differences between the Neoproterozoic Katangan Supergroup of the LFB and the Zambezi and Damaran belts. The Katangan Supergroup has a far greater metal endowment, is significantly thinner and contains limited igneous units within the basal portion of the succession (Selley et al., 2005). Selley et al. (2005) suggest that the absence of volcanism during deposition of syn-rift rocks indicates subdued crustal heat flow and low rate of crustal attenuation.

4 STRATIGRAPHY OF THE KATANGAN SUPERGROUP IN THE ZAMBIAN COPPERBELT The interpretation of the basin evolution resulting in the deposition of the rocks of the Katangan Supergroup is still controversial (e.g. Binda, 1994; Porada and Berhorst, 2000; Selley et al., 2005). The ~1.5 to 3 km thick (pre-erosional thickness of ~5 to 7 km; Annels, 1989) Neoproterozoic Katangan Supergroup in the ZCB is a package of deformed and metamorphosed sedimentary rocks unconformably overlying the basement (Fig. 2.2). North of the ZCB exists the laterally equivalent and equally extensive Congolese Copperbelt (CCB) (Table 2.1). Lower Kundelungu Group Mwashia Group Grand Conglomerate ~740Ma Emplacement of mafic lavas and intrusives in central and western Domes Region ~765 Ma Ma intrusive gabbro diamictite breccia carbonate mixed carbonate - siliciclastic siltstone-shale gritty siltstone mixed sandstone - siltstone-carbonate sandstone conglomerate Upper Roan Group Lower Roan Group Basement Kitwe Fm. Mindola Clastics Fm. evaporitic depositional environments 500m Copperbelt Orebody Member 877+/-11Ma main orebearing interval Nchanga red granite basement gneiss Figure 2.2. Lithostratigraphy of the Katangan Supergroup, Zambian Copperbelt showing approximate average unit thickness (from Selley et al., 2005). The Nkana-Mindola Deposit (NKM) is hosted at the base of the Kitwe Formation. This chapter provides a description of the stratigraphy and basin architecture of the Lower Roan Group at the NKM deposit. The Katangan Supergroup is divided into a five-fold subdivision which includes (1) Lower Roan Group (siliciclastic rock dominated succession); (2) Upper Roan Group (platformal carbonates, chaotic breccia and subordinate siliciclastics rocks); (3) Mwashia Group (carbonates and generally fine grained siliciclastics rocks); (4) Lower Kundulungu Group (glacial diamictite overlain by carbonate and carbonate-bearing clastic rocks); and (5) Upper Kundulungu Group (basal diamictite overlain by carbonate). Gabbroic rocks mainly occur in Upper Roan and Mwashia Groups. The maximum age of sedimentation is constrained by the Nchanga Red Granite and the upper sedimentation is constrained by the Sturtian glaciation (Grand conglomerate diamictites), and mafic lavas and intrusive rocks in the Domes Region (from Selley et al., 2005).

5 Table 2.1. Stratigraphic nomenclature of the Katangan Supergroup on the Zambian Copperbelt and relationship between nomenclature used at different deposits. The Mindola Clastic Formation and the Kitwe Formations are the focus of this study at the NKM deposit (modified from Cailteux et al., 2005; Selley et al., 2005; Batumike et al., 2007). 19 Group Formation Member Clemmey (1976) Kundelungu (former Upper Kundelungu) Nguba (former- Lower Kundelungu) Plateau (Ku 3) Klubo (Ku 2) Kalule Ku 1.3 Ku 1.2 Ku 1.1 Monwezi Ng 1.2 Likasi Ng 1.3 Kakontwe (Ng 1.2) Grand Conglomerate (Ng 1.1) Nkana- Mindola (mine terminology) Chambishi Nchanga (Binda and Mulgrew, 1974) Konkola Musoshi (Lefebvre, 1989) Mwashia Upper Mwashia Mwashia Upper Mwashia Middle Upper Roan Lower Ultra Far Lower Mwashia Upper Roan Bancroft Fm. Water Fm. Dolomite Fm. Upper Roan Kanwangungu Fm. Kibalonfo Fm. Lower Roan Kitwe Formation Antelope Antelope Far Water Sandy talc Shale with Shale with Kibalongo Fm. Clastic Mbr. Sediments schist grit grit Lubembe (Lefebvre, 1989) Mines Group (R.A.T.) Musoshi Fm. Chambishi Nchanga Rokana Copperbelt Chambishi Dolomite Mbr. Nchanga quartzite Mbr. Rokana Evaporites Member Copperbelt orebody Member Mindola Kafue Kafue Arenites Konkola Basal Quartzite Far water Dolomites Dolomite- Argillite Seq. Upper quartzite Near Water Sediments Ore Shale and Hangingwall Argillite Footwall Conglomerate; Arkose and argillite; Lower Conglomerate Footwall Quartzite; Basal Conglomerate Cherty Dolomite Interbedded Argillite and Dolomite Upper quartzite Interbedded Argillite and Dolomite Ore Shale Footwall Conglomerate; Arkose and argillite; Lower Conglomerate Footwall Quartzite; Basal Conglomerate Chingola Dolomite Dolomitic schist Upper Banded shale Feldspathic Quartzite Banded Sandstone Upper Pink Quartzite Shale marker Banded Sandstone Lower chart marker Lower Banded Shale Transition Arkose Arkose Conglomerate Hangingwall Aquifer Hangingwall Quartzite Chingola Formation Pelitic-Arkosic Formation Ore Shale Ore Shale F.Q. Footwall conglomerate Footwall Sandstone Porous sandstone Footwall Quartzite Pebble conglomerate Basal conglomerate Mutonda formation Kafufya Formation Chimfunsi Formation Kitotwe Mbr. Kabemba Mbr. Simbi Lubembe

6 20 (A) Congolese Copperbelt Dom es Region DRC 11 Zambian Copperbelt U-Pb uraninite U-Pb monazite U-Pb rutile Pb-Pb Cu sulfide Re-Os molybdenite Re-Os Cu-Co sulfide 1 Kamoto 2 Monwezi 3 Mindigi 4 Shinkolobwe 5 Kambove 6 Luisha 7 Luiswishi 8 Kawanga 9 Kansanshi 10 Kimale 11 Dumbwa 12 Musoshi 13 Konkola 14 Nchanga 15 Chibuluma West 16 Nkana-Mindola Hook Massif Katangan Sgp and younger strata Basement ZAMBIA 27 (B) Nchanga Red Granite 877+/-11Ma Lufilian Orogeny T1 T2 T3 T4 T5 Maximum age of Katangan sedimentation 13 Sturtian Glaciation ~ 740 Ma 4 14,15, , ,10, , Ma 800 Ma 700 Ma 600 Ma 500 Ma Figure 2.3. Summary of geochronological data associated with Cu and U mineralization in the Lufilian Fold Belt (modified from Selley et al., 2005). This figure shows the relationship of mineralizing events to significant stages of basin development. The location of the samples shown in insert A. Thermal events include: T1 ( Ma) extension-related magmatism (Key et al., 2001), T2 ( Ma) eclogite facies metamorphism in the Zambezi belt (John et al., 2003) and greenschist facies metamorphism in the Zambian Copperbelt (Rainaud et al., 2002), T3 ( Ma) felsic magmatism in the Katanga High (Hanson et al., 1993), T4 ( Ma) whiteschist facies metamorphism in the central part of the Domes Region (John et al., 2004), T5 ( Ma) post-collisional uplift and cooling throughout the Domes Region (Cosi et al., 1992; Rainaud et al., 2002; John et al., 2004). The interpretation of basin evolution and deposition of the Katangan Supergroup remains controversial (e.g. Binda, 1994; Porada and Berhosrt, 2000; Selley et al., 2005). Stratigraphic correlation between ZCB and CCB is a controversial issue based on the stratigraphic sub-division of the Katangan Supergroup. Within the ZCB, the Katangan Supergroup is preserved in several predominantly NW trending structural basins (a series of west-northwest- to north-northwest- trending synclines). These are separated by, or in some cases are entirely enclosed by, reworked Palaeoproterozoic crystalline basement including Mushi, Bwana-Ndola, Roan- Muliashi, Chambishi-Nkana, Nchanga and the Luwuishi Basins (Mendelsohn, 1961; Selley et al., 2005) (Fig. 2.4). However a regionally robust five-fold stratigraphic division has been defined for the Katangan Supergroup

7 21 (e.g. Mendelsohn, 1961; Clemmey, 1976; Annels, 1984; Cailteux, 1994; Kampunzu and Cailteux, 1999; Porada and Berhorst, 2000, Selley et al., 2005). At the deposit scale, a range of differing stratigraphic nomenclature exists for each Cu deposit on the ZCB (Table 2.1). The major lithostratigraphic units, from base to top are the (Fig. 2.2): Lower Roan Group (siliciclastic-carbonate package); Upper Roan Group (platform carbonates, siliciclastics and chaotic breccias); Mwashia Group (carbonates and generally fine-grained siliciclastics); Nguba Group (formerly the Lower Kundelungu - glacial diamictite, carbonates and minor siliciclastic); and Kundelungu Group (basal diamictite overlain by mixed carbonate and clastic rocks) is poorly defined in the Democratic Republic of Congo (DRC) and only partially preserved, due to erosion in the ZCB. The Katangan Supergroup preserved in Zambia has previously been described by Jordaan (1961), Clemmey (1976) and Binda (1994) and is summarised in the next section, including observations from this study Lower Roan Group The Lower Roan Group is subdivided into the basal Mindola Clastic Formation (MCF), consisting mainly of arenaceous strata, and the overlying siltstone-dolomite-shales of the Kitwe Formation (KF) (Clemmey, 1976) (Fig. 2.2) Mindola Clastic Formation (MCF) The MCF is characterised by significant lateral and vertical facies variations involving texturally immature breccias, conglomerates and sub-arkosic sandstones, deposited in fluvial, alluvial fan, eolian and fan-delta environments. The MCF at NKM has an average thickness of m and ranges from being absent in some areas to a maximum of 1 km at Konkola, northern ZCB. The MCF accumulated within sub-basins of limited strike extent and bounded by basement-cored topographic highs. The fault controlled origin of these basins is evidenced by their systematic west-northwest to north-northwest orientations, and the local preservation of cross-section half-graben cross-section geometries and the inverted axes of sub-basins coincide with synformal closures (Selley et al., 2005). Clemmey (1976) sub-divided the MCF into 2 members; however the classification is difficult to apply consistently, particularly where the MCF is deformed. At NKM, the Basal Sandstone Member (BSM) is distinguished from the overlying Kafue Arenite Member (KAM) by a widespread 5 to 15 m thick conglomeratic unit (Fig. 2.5) Kitwe Formation (KF) The Kitwe Formation contrasts with the MCF and displays a well defined internal layer cake stratigraphic architecture. The Kitwe Formation consists of an approximately 200 m thick sequence of sandstone, marginal marine-evaporitic argillaceous sandstone, dolomitic siltstone-sandstone and massive dolomite. The formation occurs within a 125 km long and km wide west-northwest trending belt, frequently referred to as the Shale-belt (Fig. 2.6) and has been sub-divided in to five members (Fig. 2.5) (Binda and Mulgrew, 1974; Binda, 1994). The eastern edge of the Shale Belt is poorly defined because lithostratigraphic equivalents exist on the eastern side of the Kafue Anticline (Binda, 1994). Binda and Mulgrew (1974) and Porada and Berhorst (2000) indicate that the western margin is defined by the pinch-out of the Copper Orebody Member (COM) with gabbro, dolomitic talc-schist and brecciated dolomites directly overlying the MCF. The MCF and KF occurring at NKM are the focus of detailed descriptions and discussion in Chapter 3. The basal COM is the principal host to Cu-(Co) mineralisation (Clemmey, 1976). This unit is commonly referred to as the Ore Shale west of the Kafue Anticline, and east of the Kafue Anticline, in the vicinity of

8 22 Katanga High Synclinorial Belt Domes Region External Fold & Thrust Belt A A 100km Katangan Supergroup upper lower & middle undifferentiated Basement overriding plate overthrust plate Pan-African age granite Figure 2.4. Schematic cross section (section A-A ) of the Lufilian fold belt showing the variation in the structural style between the tectonic zones (modified from Porada, 1989; Selley et al., 2005). the Mufulira deposit, as the Mudseam (Binda, 1994). Directly overlying the COM is the marginal marine sandstone-siltstone of the Rokana Evaporite Member (REM) (Clemmey, 1978). Higher in the sequence are the Nchanga Quartzite (NQM) and Chambishi Dolomite (Fig. 2.5 and 2.7) Upper Roan Group The contact between the Lower Roan Group and the Upper Roan Group is poorly defined however it is historically distinguished by the predominance of carbonate strata (Mendelsohn, 1961) (Fig. 2.2). Selley et al. (2005) define the base of the Upper Roan Group by the appearance of >1m thick, regional extensive dolomite beds. The Upper Roan Group consists of laterally extensive decimetre to metre scale, upward fining cycles of sandstone, siltstone, dolomite, algal dolomite and patches of anhydrite. The preserved thickness of the sequence is variable, ranging from ~30 m to >800 m (Selley et al., 2005). The Upper Roan Group at NKM consists of ~300 m thick sequence of interbedded argillites, dolomitic argillites, dolomites, dolomitic sandstone and argillaceous dolomites. All units are laterally continuous across the NKM area, however, no studies of the Upper Roan Group were undertaken as part of this research due to the poor nature of the exposures. The Upper Roan Group may contain stratabound and discordant breccia units. These range from centimetres to hundreds of metres in scale, and appear to have accommodated much of the thickness variations in the Upper Roan Group (Wendroff, 2000; 2003; Selley et al., 2005). The breccias are composed of intraformational fragments within a matrix of carbonate, albite, quartz, anhydrite and/or chlorite (Annels, 1984). Selley et al. (2005) report that these breccias cross cut down stratigraphy to the south and west in the Mufulira, Konkola, Luanshya Basin and Chambishi Basin areas. The breccia bodies had developed along former evaporitic horizons, similar to the breccias occurring in the DRC described by Francois (1973) and Jackson et al (2003), however, Wendroff (1997, 2003) suggested the breccia formed as a molasse deposit Mwashia Group The Mwashia Group is a shale dominated sequence conformably overlying the Upper Roan Group (Fig. 2.2). Unlike the underlying Roan Group, relatively few Cu-Co deposits have been identified within the Mwashia Group rocks and consequently there are few published studies of the Mwashia Group and the overlying Kundelungu Group. Within the ZCB, Selley et al. (2005) describe the approximately 400 m thick Mwashia Group as consisting of a lower dolomite package overlain by a dolomite-siltstone-mudstone sequence capped

9 23 Mine Terminology at Nkana-Mindola Stratigraphic Nomenclature (Modified from Clemmey, 1976) Upper Roan Group Ultra Far Water Sediments Far Water Sediments Antelope Clastics Member Bancroft Dolomite Formation Upper Roan Group Lower Roan Group Far Water Formation Upper Quartzite Near Water sediments Hangingwall Quartzite Ore Shale (See associated diagram) Footwall Conglomerate Chambishi Dolomites Member Nchanga Quartzite Member Rokana Evaporites Member Copperbelt Orebody Member (see associated diagram) Kitwe Formation Lower Roan Group Main stratigraphic package under investigation main orebearing interval Footwall Sandstone Lower Conglomerate Basal Sandstone Kafue Arenites Member Basal Sandstone Member (new terminology) Mindola Clastic Formation Basal Quartzite Basal Conglomerate/Breccia Undulating unconformity surface Basement Complex Basement 10m breccia sandstone mixed sandstone - siltstone - carbonate basement gneiss carbonate mixed carbonate - siliciclastic siltstone - shale conglomerate gritty siltstone Nchanga granite Figure 2.5. Detailed lithostratigraphy sub-division of the Lower Roan Group at Nkana-Mindola. The local mine terminology is included for reference. The focus of this study is on the Mindola Clastic Formation and the basal portion of the Kitwe Formation, which hosts the majority of economic copper mineralisation. by a siltstone-mudstone-carbonaceous mudstone sequence (Fig. 2.7). The base of the Mwashia Group is defined by the polylithic breccia in the DRC and the upper portion of the group is dominated by a clastic sequence (Cailteux, 1994). As with the Upper Roan Group, no exposures of the Mwashia Group were examined during this study at NKM Nguba and Kundelungu Groups The base of the Nguba Group (Ng 1.1 of Nguba - Cailteux and Kampunzu, 2002) is marked by the ~ m thick Grand Conglomerate (Fig. 2.2). This unit is a regionally extensive sequence of debris flows and

10 24 diamictites, intercalated with minor, thin interbeds of siltstone and sandstone (Binda and Van Eden, 1972). Classical interpretations suggest the group is a chronostratigraphic equivalent of the oldest globally recognized Neoproterozoic Snowball Earth glaciation event and is correlated with the Sturtian diamictites deposited at ~740Ma (Hoffman, 1999). In the Democratic Republic of Congo (DRC), the Grand Conglomerate is up to 600m thick and has a broad temporal association with ~760 to 750 Ma mafic extensional igneous activity including gabbroic sills and mafic volcanic flows and tuffs (Armstrong et al., 1999; Key et al., 2001; Rainaud et al., 2002). Limited data is available for the Kundulungu Group at NKM. An intersection of black to grey limestones in the Mindola Central Dam Wall has been assigned to the Kakontwe Limestone Formation and is overlain by purple to grey-black argillites. The series occupies the synclinal hinge of the Nkana Syncline in the northern and central areas at NKM Intrusive Rocks Mafic and ultramafic intrusive rocks of the Upper Roan are of continental tholeiitic, alkaline and EMORB basaltic composition and comprise a minor proportion of the Katangan sequence. These intrusive bodies are in close spatially association with breccia units The bodies are generally discontinuous and are typically strongly altered, suggesting they were emplaced as sills, however, Porada and Berhorst (2000) suggest the bodies have been tectonically emplaced. Variations in the composition of the mafic rocks record different stages of continental break-up, from pre-continental rift to a continental rift system and then to an oceanic rift system (Kampunzu et al., 2000). There are few documented intrusive rocks within the Nkana-Mindola area. Meta-gabbroic rocks have been identified east of the Mindola pit near the Mindola Dam and intrude the Upper Roan, Mwashia and Lower Kundelungu Groups (Mendelsohn, 1961). These rocks are medium to coarse-grained, dark-grey to greenish in colour with a high biotite composition (Jordaan 1961) and contain slivers of metasediments. The surface expression of the intrusive bodies broadly approximates the shape of the Nkana Syncline. Previous surface mapping of the NKM mining lease identified several gabbroic bodies. Outcrop pattern suggests the gabbroic rocks have been folded. According to Whyte and Green (1971), syenitic to gabbroic rocks at the Chibuluma Deposit have been extensively altered and metamorphosed to scapolitized amphibolitic rocks. The most significant intrusive rock at Mindola are lamprophyre dykes. At approximately 2000 N at the Mindola Shaft, a 10m to 30m wide east southeast steeply dipping fine-grained, biotite rich dyke crosscuts basement schists and the Lower Roan Group rocks. On the upper levels at Mindola Shaft the same dyke dips west-north-west at shallow angles (Jordaan, 1961). Jordaan (1961) classified the lamprophyre dyke as a kersantite, based on the petrographic and chemical analyses of eight samples. The dyke has poikilitic plagioclase laths set in a fine ground mass of quartz, mica and epidote. Biotite and chlorite grains impart an overall weak schistosity to the rock. Accessory minerals include skeleton crystals and spiral form ilmenite. The margins of the dyke are diffuse and the contact with the basement schist is difficult to recognise due to thermal metamorphism of the wallrock and the interfingering of dyke rock with argillaceous rocks (Jordaan, 1961). Minor copper sulphides, in the form of bornite and chalcocite, are associated with the margins of dyke when it cross cuts through basement lithologies and commonly where it is interfingered with the argillites of the COM. Other cross cutting dykes in the ZCB occur at River Lode, Nchanga and at the North Orebody Konkola (Mendelshon, 1961) Correlation with the Congolese Copperbelt (CCB) To north of the ZCB exists the lateral equivalent and equally extensive CCB. Stratigraphic correlation between the CCB and ZCB are based on the stratigraphic sub-division of the Katangan Supergroup. Correlation of the

11 25 upper Mwashia and Kundelungu Groups have been documented (e.g. Binda, 1994; Cailteux et al., 1994; Porada and Berhorst, 2000), however correlation of the underlying Upper Roan and Lower Roan Groups between the CCB and ZCB remains partially unresolved. The most widely accepted correlation suggests the Kitwe Formation of the Lower Roan Group is equivalent to the Congolese Mines Subgroup (Table 2.1) (Cailteux et al., 1994; Binda and Porada, 1995; Kampunzu and Cailteux, 1999). The Roches Argilo-Talqueuses (R.A.T) is the oldest unit and correlates to the siliciclastic rocks of the Lower Roan Group in the ZCB, however, tectonic displacement between the Mines Subgroup and R.A.T. generally blurs the relationship between the units. Porada and Berhorst (2000) suggest that many of the units are laterally equivalent facies stacked by northeast directed thrusting. B Konkola Dome 28 Chililabombwe Dome Mokambo Dome Shale Belt Lower and Upper Kundelungu Groups Gabbro Chingola Chambishi Basin Kafue Anticline Upper Roan and Mwashia Groups Lower Roan Group Basement Kitwe Ndola Luanshya Basin 13 B 20KM Figure 2.6. The distribution of the Ore Shale belt on the Zambian Copperbelt (modified from Selley et al., 2005). See figure 2.7b for stratigraphic correlation along section line B-B.

12 200 m 26 A B Lower and Upper Kundelungu groups Roan & Mwashia groups Mufulira basement Kitwe B A diamictite polylithic and crackle breccia siltstone and shale sandstone dominant carbonate dominant Lower Kundelungu Gp Mwashia Gp A Upper Roan Gp A A KLB145 KW24 KW26 KW22 LB18 L62 L79 L80 B B NW SE Konkola Nchanga Chambishi Nkana Luanshya Mufulira Kitwe Formation Lower Roan Mindola Clastic Upper Roan Carbonate MW107 Kafue Anticline DH218 DH219 IT27 IT25 Basement Unconformity 75m B. Upper Roan Roan Antelope Member Chambishi Dolomite Member Nchanga Quarzite Member Shale Rokana Evaporites Member Copperbelt Orebody Member Footwall arenite and arkose Footwall conglomerate Mava Schist & quartzite Basement granite Basement Lufubu Schist

13 PAN-AFRICAN OROGENESIS DEFORMATION OF THE LUFILIAN FOLD BELT (LFB) The Lufilian Fold Belt (LFB) is a north verging fold-thrust belt which formed during the closure of the Neoproterozoic basins. The LFB is defined on the northern margin by relatively undeformed uppermost Katangan Supergroup while the southern margin is marked by the sinistral, east-northeast trending Mwembeshi shear zone. Movement in the shear zone has resulted in the present juxtaposition of low-grade LFB rocks to high-grade rocks of the Zambezi Belt (Unrug, 1989). Recent research specifically documents the deformational events associated with the Pan-African orogenesis. The Pan-African orogenesis is manifested as major thrusting, backfolding and backthrusting in response to convergent tectonics (e.g. Daly et al., 1984; Daly, 1986; Unrug, 1987; Kampunzu and Cailteux, 1999; Hanson, 2003). Despite numerous significant studies (e.g. Daly, 1986; Unrug, 1989; Kampunzu and Cailteux, 1999; Porada and Berhorst; 2000; Hanson, 2003), the tectonic evolution remains unresolved and Table 2.2 is a summary of several different tectonic models for the LFB. The Lufilian orogenesis is thought to span ~100 m.y. The oldest metamorphic ages of greenschist facies rocks in the ZCB are U-Pb monazite (592 ± 22 Ma) and Ar-Ar biotite (585.8 ± 0.8 Ma) (Rainaud et al., 2002). Hanson et al. (1993) constrained the main phase of orogenesis to between ~560 and ~530 Ma using U-Pb zircon dating of syn- to post-tectonic granites and rhyolites in the Katangan high. John et al. (2004) report U-Pb monazite ages of ~530 Ma for peak metamorphism for white schist facies rocks in the central and western Domes region. Postorogeneic cooling is recorded by the widespread 510 to 465 Ma Ar-Ar biotite, Rb-Sr muscovite ages (Cosi et al., 1992; Torrealday et al., 2000; Rainaud et al., 2002; John et al., 2004) (Fig. 2.3). The LFB consists of four north verging tectonic domains. De Swardt and Drysdall (1964) suggested the LFB could be divided into four orogenic zones - the External Fold and Thrust Belt, the Domes region the Synclinorial belt and the Katangan High (Fig 2.1b and 2.5). The ZCB occurs adjacent to the easternmost basement inlier of the Domes region while the CCB occurs within the External Fold and Thrust belt. The boundary between the two coincides with an abrupt southward increase in metamorphic grade and structural style (Ramsay and Rigdeway, 1977; Francois and Cailteux, 1981; Key et al., 2001; Selley et al., 2005). Rocks in the Domes region were metamorphosed at upper greenschist to amphibolite metamorphic grade. Upper greenschist facies rocks occur in the eastern part of the region, where high amplitude folding dominates the structural style (Daly, 1986). Basement involved deformation throughout the Domes Region implies thick-skinned style of deformation and the position of the basement inliers to reflect structural culminates developed above ramps that splayed off a deep crustal detachment (Daly et al., 1984; Daly, 1986). In the western and central Domes areas, Cosi et al. (1992) and Key et al. (2001) provide evidence of large-scale thrusting by the existence of basement-cored nappes emplaced within the Katangan strata and juxtaposition of units of different metamorphic grade. OPPOSITE: Figure 2.7. a). Stratigraphic correlation of the Upper Roan Group on the eastern flank of the Kafue Anticline (modified from Selley et al., 2005). b). Stratigraphic correlation of the Lower Roan Group of the Katangan Supergroup on the western flank of the Kafue Anticline, including a comparison with the Mufulira deposit on the eastern flank (modified from Binda and Mulgrew, 1974; Binda, 1994).

14 28 De Swardt and Drysdall (1964) defined the External Fold and Thrust Belt portion of the LFB as a foreland facing outer zone and record fragmentation, repetition and inversion of the Katangan stratigraphy (Fig. 2.8). There is little evidence of basement involvement in the exposed structural pile suggesting a more thin-skinned structural style compared to the Domes Region to the south (Porada and Berhorst, 2000; Selley et al., 2005). Decoupling along evaporitic strata, positioned in the middle Katangan stratigraphy, accounts for the lack of basement involvement in this portion of the LFB (Porada and Berhorst, 2000; Jackson et al., 2003; Selley et al., 2005). The western portion of the LFB has complex structures that trend obliquely to the regional folds and thrusts. The Roan and Kundelungu sequences in this area are allochthonous and Jackson et al. (2003) proposed salt tectonics as the dominant mechanism for the formation of Roan gigabreccias, which are characteristic of the External Fold and Thrust belt. The relationship of the Domes Region to the Synclinorial Belt is uncertain. One model suggests a major change in the basin architecture was coincident with thrust dislocation between the Domes region and Synclinorial belt (e.g. Cosi et al., 1992; Porada and Berhorst, 2000). This boundary is interpreted as an abrupt break on a southward attenuating passive margin (Porada and Berhorst, 2000). To the north, a succession of marginal marine platformal-lagoonal rocks were deposited, while on the southern side of the break, deeper water facies dominated, however, Selley et al. (2005) suggested there is no evidence for a deeper marine sequence in the Synclinorial belt. 2.6 METAMORPHISM Detailed accounts of the metamorphic facies are presented in Ramsay and Ridgway (1977), Francois and Cailteux (1981), Cosi et al. (1992) and Tembo (1994). The Proterozoic to early Palaeozoic rocks of the LFB vary from low-grade to high-grade metamorphic mineral assemblages, in part reflecting the complex tectonic development of the region. Ramsay and Ridgway (1977) recognised two non-parallel metamorphic belts. Recrystallization of the rocks is extensive with the main metamorphic minerals observed being biotite and sericite, and lesser amounts of scapolite, tourmaline, chlorite, tremolite-actinolite, epidote and apatite. The Lufilian metamorphic belt curves along the southern margin of the broader scale LFB and the Luangwa-Kariba metamorphic belt covers the eastern and south-eastern region of the Zambia. Ramsay & Ridgeway (1977) concluded that all the rocks younger than the basement complex in the LFB were metamorphosed in a single metamorphic cycle of Pan-African age. The metamorphic isograds parallel the broad structural framework, and the degree of metamorphism increases from the outer zones of the External Fold and Thrust Belt and into the Domes region. Prehnite-pumpellyite facies assemblages are recorded in the outer areas of the External Fold and Thrust Belt, shifting to greenschist facies metamorphism in the inner portions of the External Fold and Thrust Belt and further grading into amphibolite facies in the Domes Region (Kampunzu et al., 2000). Whiteschist and high pressure eclogites occur to the south of the Domes Region (Cosi et al., 1992). The lowest grade of metamorphism on the ZCB occurs at Konkola and Mulfulira, and increases to upper greenschist to amphibolite facies towards the southeast. Within the Roan-Muliashi basin epidote-amphibolite facies grade is reached, while carbonate rich rocks at Nkana consist of tremolite and talc (Mendelsohn, 1961). 2.7 Cu-Co MINERALISATION OF THE ZCB The major deposits in the ZCB are distinctly aligned parallel to the Kafue Anticline (Fig. 2.9) and have been interpreted as indicating the presence of a deep structural feature (e.g. Annels, 1989) or a palaeoshoreline (e.g. Clemmey, 1976). Two broad classes of sediment-hosted Cu deposits occur within the ZCB (e.g. Fleischer, 1976;

15 29 Luanshya Basin Chambishi Basin Nchanga- Chingola district Konkola district Eastern Kafue Anticline Lower Kundelungu Group Baluba Luanshya Mindola Nkana Chanbishi SE Chanbishi Chibuluma Chibuluma West Chibuluma South Mwambashi B Mwambashi A Pitanda Samba Fitula Mimbula Chingola A & C Chingola B Chingola D Chingola E Chingola F Nchanga Konkola North Musoshi Bwana Mkubwa Ndola West Mufulira Luansobe Lubembe Frontier Lonshi? basement Lower Roan Upper Roan Mwashia Group Group Group Mindola Kitwe Clastics Fm. Fm. 500m Copperbelt Orebody Member (and equivalents) gritty siltstone siltstone-shale sandstone-siltstone-carbonate diamictite sandstone breccia conglomerate carbonate granite, gneiss, schist mixed carbonate-siliciclastic Cu ± Co Mineralization diamictite/carbonate-hosted carbonate/breccia-hosted argillite-hosted mixed argillite-arenite arenite-hosted basement-hosted "hangingwall" deposits "footwall" deposits Figure 2.8. Two broad categories of the sedimentary-hosted copper mineralisation on the ZCB can be defined. Mineralisation is either the arenite hosted or argillite hosted style, however within a single deposit both styles of mineralisation can occur (modified from Selley et al. 2005). The NKM deposit is primarily an argillite hosted deposit, however mineralisation transgresses the contact between the Mindola Clastic Formation and the Copperbelt Orebody Member.

16 30 Selley et al., 2005): the arenite-hosted mineralised systems and the classical argillite-hosted deposits (Fig. 2.8) and mineralisation commonly is not confined to one specific stratigraphic horizon. However, the argillitehosted deposits are generally confined to the lower portions of the COM (e.g. Nkana Mindola and Nchanga orebodies) (Fig. 2.8), while the arenite-hosted systems are mainly recognised within the MCF (e.g. Chibuluma, Chibuluma West, Mwambashi B, and Chingola B). Argillite hosted Cu mineralisation also occurs at the higher levels of the Kitwe Formation and within the Mwashia and lower Kundelungu Groups. Table 2.3 summarises the key features of the major deposits of the ZCB. The major orebodies are preserved in synforms within basement inliers (Unrug, 1989). These structures have been interpreted as former basins which controlled the deposition of the rocks of the Lower Roan Group and influenced the localisation of sulphide mineralisation (Mendelsohn, 1961; Selley et al. 2005). Cu mineralisation transgresses stratigraphy, however, each orebody has a grossly stratabound geometry. Within a single deposit several types of mineralisation maybe recognised, including disseminated, pre-folding veinhosted, post-folding vein hosted, shear-zone-hosted and oxidation-supergene mineralisation. Significant vein hosted Cu mineralisation also occurs in the western ZCB at the Kansanshi Deposit, which is hosted at a higher level in the stratigraphic succession (Broughton et al. 2002). In addition to Cu mineralisation hosted within the Katangan Supergroup, significant disseminated Cu mineralisation occurs in basement lithologies (e.g. Lumwana, Samba deposits). Konkola Dome Chililabombwe Dome Chingola Chambishi Basin Kafue Anticline Mokambo Dome Shale Belt Recent Discovery Cu-(Co) Deposit (surface projection) Lower and Upper Kundelungu Groups Gabbro Upper Roan and Mwashia Groups Lower Roan Group Kitwe 28 Basement 13 5 Luanshya Basin Ndola 31 20KM Figure 2.9. Geological map of the Zambian Copperbelt and the location of the major Cu-Co deposits hosted by the Katangan Supergroup (modified from Jordaan, 1961; Fleischer et al., 1976; Selley et al., 2005). 1 Luanshya, 2 Roan Extension, 3 Baluba, 4 Lufubu South, 5 Chibuluma South, 6 Chibuluma West, 7 Chibuluma, 8 Nkana-Mindola, 9 Chambishi SE,10 Chambishi, 11 Pitanda, 12 Mwambashi A, 13 Mwambashi B, 14 Samba, 15 Fitula, 16 Mimbula, 17 Chingola A-F, 18 Nchanga, 19 Fitwaola, 20 Konkola, 21 Konkola North, 22 Musoshi, 23 Lubembe, 24 Luansobe, 25 Kasaria, 26 Mufulira, 27 Frontier (Lufua), 28 Mwekera, 29 Ndola West, 30 Itawa, 31 Bwana Mkubwa, 32 Lonshi, 33 Mokambo.. (Sourced from Darnley (1960), Mendelsohn (1961), Annels (1984), Fleischer (1984), Sweeney and Binda (1989) and Selley et al., 2005).

17 31 Table 2.2. Summary of the recognized key structural events in Zambia during the Lufilian Orogeny (~600Ma to 500 Ma). International lithostratigraphic subdivision and orogenic cycle Interpretations from Francois (1993); Cahen et al. (1984) Interpretation from Kampunzu and Cailteux (1999) and Hanson (2003) Event and Age Regional effect Event and Age Regional Effect Paleozoic Transverse folding - ~503 Ma Transverse undulations to the main trend of the Lufilian arc Chilatembo Late transverse folding NeoProterozoic (Lufilian Orogeny) Monwezian ~ 602 Ma Kundelunguian ~ 656 Ma Epeirogenesis Age? Kolwezian 656 Ma Lusakan Folding Lomamian Orogeny E-W faulting Folds with axial planes vertical or dipping N in the external folds of the Lufilian Arc Uplift in and near the Kundelungu Plateau Folds with axial planes dipping S. Nappes displaced several tens of km from S to N in southern DRC. Monwezian Kolwezian Strik-slip and escape bloack tectonics Lateral extrusion with cumulative displacement ~ 130km Clockwise rotation of crustal blocks and related development of convex structure of the Lufilian arc. Northward fold and thrust tectonics present day orientation of the Lufilian arc: E-W trend in the western sector and NW-SE in the eastern part. Major vergence to the N, back folding to S Supergene and oxidation ore minerals commonly overprint hypogene sulphides in the near surface environment. At NKM, a mixed oxide-sulphide assemblages occur within 100m of the surface Jordaan (1961). Malachite and chalcocite have been recorded at depths of > 600m in the Nchanga Lower Orebody and >1km at the Konkola North Deposit (McKinnon and Smit, 1961; Pollington and Bull, 2002) Argillite-hosted Cu deposits The argillite-hosted Cu deposits of the COM vary lithologically from dolomitic siltstones, siltstones and minor sandstones (e.g. Mindola and Roan Antelope) to black, carbonaceous shale orebodies (e.g. Nkana South). Unmineralised intervals occur at sites where the facies changes to either a massive arenaceous or carbonate facies (e.g. Annels, 1984) Arenite-hosted Cu deposits The arenite-hosted deposits account for approximately 30% of known Cu-Co mineralisation while argillitehosted deposits comprise the remainder. The small high grade footwall arenite-hosted mineralisation occurs within condensed sections of the Mindola Clastic Formation such as at Mwambashi B (Selley and Bull, 2002; Selley et al. 2005) (Fig. 2.10). However, arenite-hosted Cu orebodies situated stratigraphically above the COM also occurs (e.g. Nchanga-Chingola, Mufulira) (McGowan et al., 2003; Selley et al., 2005). The mineralogical composition of the arenite-type deposit is complex and predominantly controlled by variations in feldspars, mica and organic carbon. The full spectrum of the two lithological end-members, hosting the different styles of mineralisation, can occur within a single copper deposit, forming a complex, transgressive mineralised system.

18 32 W MW 5 BN7 BN26 BN10 BN14 E BN m mineralized interval Upper Roan Gp middle Kitwe Fm. Copperbelt Orebody Mbr Mindola Clastics Fm. basement granite dolomite, sandstone and gabbro argillaceous sandstone and siltstone carbonaceous shale sub-arkose conglomerate talus breccia granite Figure The stratigraphic-structural position of the Cu mineralization at the arenite hosted Mwambashi prospect. Cu mineralization at the Mwambashi prospect is hosted in the MCF. There is a close relationship between basement geometry and the distribution of mineralization at both deposits (modified from Selley and Bull, 2003) Chambishi Basin The Kafue Anticline dominates the regional structure in the central and southern corner of the ZCB (Fig. 2.11). To the east is the Mufulira Syncline while on the western flanks are the Chambishi and Roan-Mulashi Basins (synclines). Within the Chambishi Basin, the metasedimentary rocks of the Katangan Supergroup are enclosed by basement granites, the Lufubu Schists and the Muva metasediments, and intrusive, sill-like gabbroic bodies. Existing geological maps of the Chambishi Basin were used to define macroscopic structural domains. The southeastern corner of the basin is dominated by the NW striking Nkana Syncline, while in the northern area of the basin WNW trending folds are common. The fold patterns exhibit evidence of inheritance from pre-existing basement structures, including partitioning of strain, nucleation of folds parallel to inverted rift margins, and deflected orientations of the Lower Roan-Basement contact above inverted growth faults (Croaker and Selley, 2003; Selley et al., 2003, 2005). In the northern and western areas of the basin, the broad WNW striking synclines are separated by fault bounded basement inliers. 2.8 Cu-Co DEPOSITS OF THE CHAMBISHI BASIN The Chambishi Basin has several significant copper deposits hosted within arenite and argillite sequences and comprises a significant proportion of the total copper resource on the ZCB. The Chambishi Basin is host to six significant Cu deposits with the largest being the Nkana-Mindola Mine. Four significant deposits occur

19 33 CHAMBISHI WEST PITANDA CHAMBISHI MAIN MWAMBASHI A KAFUE CHAMBISHI SOUTHEAST PROSPECT River MWAMBASHIB Mwambashi MINDOLA RIVER CENTRAL CHIBULUMA WEST CHIBULUMA EAST KITWE SOUTH OREBODY CHIBULUMA SOUTH 10KM Gabbro Lower and Middle Kundelungu Basal Kundelungu - Kakontwe Limestone and Basal Tillite Mwashia Group Upper Roan Group Lower Roan Group Granite Muva Lufubu Lusaka Mines and known Ore Deposits Figure Geological map of the Chambishi basin. The NKM deposit is situated in the south eastern corner of the Chambishi Basin (modified from Garlick, 1961 and Jordaan, 1961).

20 34 Table 2.3. The key geological and mineralisation characteristics of the recognized copper deposits occurring in the Zambian Copperbelt. DEPOSIT Estimated Reserves- Resources (~ 1989 Mt Grade ~ Cu %, ~ Co % ~ Ag g/t Konkola % Cu 2.7 g/t Ag Nchanga % Cu 2.7 g/t Ag Mufulira % Cu 2.7 g/t Ag Chambishi % Cu 15 g/t Ag Chambishi Southeast Chibuluma South Chibuluma East & West Deposit Type Argillite Stratabound Bn, Cpy, Cc, Py and Ag Argillite and arenite Mineralisation Host Lithology Footwall Lithology Stratabound Bn, Cpy, Cc, Py and Ag Arenite Stratabound Bn, Cpy, Cc, Py and Ag Argillite Stratabound Bn, Cpy, Cc, Py and Ag % Cu Argillite Stratabound Bn, Cpy, Cc, Py % Cu Arenite Stratabound Bn, Cpy, Cc, Py % Cu 0.21 % Co 2.7 g/t Ag Nkana % Cu 0.17 % Co Baluba % Cu 0.15 % Co Luanshya % Cu 2.7 g/t Lumwana % Cu Co Kinsanshi % Co Mwambashi B 0.17 g/t Au Arenite Stratabound Bn, Cpy, Cc, Py Argillite Stratabound Bn, Cpy, Cc, Py Argillite Stratabound Bn, Cpy, Cc, Py Argillite Stratabound Bn, Cpy, Cc, Py Basement? Stratabound Bn, Cpy, Cc, Py Vein hosted Kundelungu Disconcordant & concordant Cpy, Py Arenite Stratbound Cpy-Bn Laminated siltstone and carbonate Siltstone; Feldspathic quartzite Feldspathic sandstone and siltstone Biotitic argillite, dolomite Carbonaceous Shale and argillite Sericitic sandstones and quartzites Hematite arenites and sandstone, conglomerate Sandstone, quartzites and shales Conglomerate, quartzites and sandstone-siltstone Alteration-Evaporites Zonation References Dolomite and anhydrite pseudomorphs, K-feldspar Broughton, 2003 Kirkham, 1989 Sweeney and Binda, 1984 K-fledspar and sericte Cpy+Bn>Cpy>Py Voet and Freeman, 1976 Kirkham, 1989 Mckinnon and Smit, 1961 McGowan et al Anhydrite, K-feldspar and sericite Cc-Bn-Cpy Kirkham, 1989 Scott, 2003 Brandt et al., 1961 Arkoses to conglomerate Anhydrite, K-fledspar Cc>Bn>Cpy>Py Kirkham, 1989 Annels, 1989 Quartzites, conglomerate, sandstone-siltstone Sericitic arenites and quartzites Sericitic sandstones Sericitic arenites and quartzites Dolomite, dolomitic argillite and carbonaceous shale Carbonaceous argillite and shale Carbonaceous argillite and shale Conglomerate, arkoses, feldspathic sandstone Conglomerate, arenites and argillite Conglomerate, quartzite and argillites Anhydrite, K-fledpsar and dolomite Kirkham, 1989 Annels, 1989 Bull and Selley, 2003 Sericite, albite Cc>Bn>Cpy>Py Kirkham, 1989 Winfield, 1961 Sericite, albite Cc>Bn>Cpy>Py Kirkham, 1989 Selley et al, 2002 Anhydrite, dolomite, K-feldspar, albite Gensis and schist Schist and quartzite Sericite, quartz, phlogopite Schist and carbonate veins Bn-Cpy>Ca>Cpy >Ca>Py Sericite Cc>Bn>Cpy>Py >Cc Kirkham, 1989 Jordaan, 1961 Kirkham, 1989 Annels et al Simmonds, 1983 Py>Cpy>Bn>Cc Kirkham, 1989 Mendelsohn, 1961 Kirkham, 1989; Bernau, 2007 Schist and quartzite Albite Brougton et al Torrelday et al Sandstone Conglomerate, sandstonesiltstone K-feldspar Selley et al. 2003