François Turlin
email: francois.turlin@univ-lorraine.fr

Aurélien Eglinger

Olivier Vanderhaeghe

Anne-Sylvie André-Mayer

Marc Poujol

Julien Mercadier

Ryan Bartlett

Franc ¸ois Turlin

Anne-Sylvie André- Mayer

geochronological data on the kyanite-micaschists hosting the Cu(-U) Lumwana deposit in the Western Zambian Copperbelt of the Lufilian belt

Keywords: Copper, Amphibolite facies, U-Th-Pb geochronology, Pan-African orogeny, syntectonic mineralization

come     Synmetamorphic Cu remobilization during the Pan-African orogeny: Microstructural, petrological and

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Introduction

Cu deposits are hosted by a wide variety of rocks including sedimentary, metamorphic and magmatic rocks (Dill, 2010 and references therein). Among them, sediment-hosted stratiform Cu deposits represent around 25% of the Cu production at a mean grade of 2.4% (Hitzman et al., 2005;Selley et al., 2005). The Lufilian orogenic belt (Fig. 1), straddling the border between the Democratic Republic of Congo (DRC) and Zambia, formed during the Pan-African orogenic cycle and contains the largest sediment-hosted stratiform Cu province in the world, the Central African Copperbelt [START_REF] Cailteux | Genesis of sediment-hosted stratiform copper-cobalt deposits, central African Copperbelt[END_REF][START_REF] Muchez | Diagenetic origin and multiphase modification of world-class Cu-Co deposits in the Central African Copperbelt[END_REF]Selley et al., 2005).

FIGURE 1

This Neoproterozoic belt is mainly divided into two tectono-metamorphic zones from north to south [START_REF] De Swardt | Precambrian geology and structure in central Northern Rhodesia[END_REF]): (i) the External fold-and-thrust belt in the north and (ii) the Domes region (in the south of and on the border between DRC and Zambia, Fig. 1). The External fold-and-thrust belt, with metamorphism not exceeding greenschist facies (Fig. 1, [START_REF] Key | The western arm of the Lufilian Arc in NW Zambia and its potential for copper mineralization[END_REF][START_REF] Torremans | Remobilisation features and structural control on ore grade distribution at the Konkola stratiform Cu-Co ore deposit, Zambia[END_REF] contains (i) Cu-Co (e.g. Kamoto, El Desouky et al., 2009;[START_REF] Muchez | Anhydrite pseudomorphs and the origin of stratiform Cu-Co ores in the Katangan Copperbelt (Democratic Republic of Congo)[END_REF][START_REF] Muchez | Diagenetic origin and multiphase modification of world-class Cu-Co deposits in the Central African Copperbelt[END_REF] and Pb-Zn-Cu deposits (e.g. Kipushi; [START_REF] Batumike | Lithostratigraphy, basin development, base metal deposits, and regional correlations of the Neoproterozoic Nguba and Kundelungu rock successions, central African Copperbelt[END_REF]Kamona et al., 1999;Kampunzu et al., 2009) defining the Congolese

Copperbelt (Selley et al., 2005), and (ii) Cu-Co deposits around the Kafue Anticline (e.g. Konkola, Nchanga, Selley et al., 2005) designated as the Eastern Zambian Copperbelt. The Domes region, also known as the Western Zambian Copperbelt (Selley et al., 2005), contains Cu-Co deposits (e.g. Lumwana, [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF][START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF][START_REF] Nowecki | Tracing seawater evaporation and its role in the formation of sedimenthosted stratiform copper deposits[END_REF] and Co-Ni-Cu (e.g. Kalumbila, [START_REF] Capistrant | Geology of the Enterprise Hydrothermal Nickel Deposit, North-Western Province, Zambia[END_REF][START_REF] Steven | A metamorphosed Proterozoic carbonaceous shale-hosted Co-Ni-Cu deposit at Kalumbila, Kabompo Dome: The Copperbelt ore shale in northwestern Zambia[END_REF], around domes cored by gneisses and migmatites (Fig. 1, [START_REF] Hitzman | The Central African Copperbelt: Diverse stratigraphic, structural and temporal settings the Kampunzu[END_REF], recording the highest metamorphic P-T conditions (up to upper amphibolite facies, [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF][START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF],

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2013; [START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF]Eglinger et al., 2014b, accepted;John et al., 2004). These copper occurrences are locally associated with uranium mineral occurrences [START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF][START_REF] Decrée | SIMS U-Pb dating of uranium mineralization in the Katanga Copperbelt: Constraints for the geodynamic context[END_REF][START_REF] Eglinger | Geochemical signatures of uranium oxides in the Lufilian belt: From unconformity-related to synmetamorphic uranium deposits during the Pan-African orogenic cycle[END_REF].

In the Congolese and Eastern Zambian Copperbelts, these deposits are hosted within the lower part of the Neoproterozoic Katanga metasedimentary sequence, the Roan (Mines Subgroup, e.g. Kamoto deposit, Fig. 2, [START_REF] Muchez | Diagenetic origin and multiphase modification of world-class Cu-Co deposits in the Central African Copperbelt[END_REF] and Lower Roan Group (e.g.

Konkola deposit, Fig. 2, Selley et al., 2005) respectively. In addition, recent studies brought geochronological evidence that the Cu mineralization in the Congolese and Eastern Zambian

Copperbelts' sediment-hosted stratiform deposits are multistage, from early-to intermediatediagenetic dated between ca. 820 and 650 Ma (Barra and Broughton, unpublished data in Selley et al., 2005;[START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript | Multi-Stage mineralization in the Zambian Copperbelt based on Re-Os isotope constraints[END_REF][START_REF] Muchez | Diagenetic origin and multiphase modification of world-class Cu-Co deposits in the Central African Copperbelt[END_REF][START_REF] Richards | Pb isotope constraints on the age of sulfide ore deposition and U-Pb age of late uraninite veining at the Musoshi stratiform copper deposit, Central Africa Copperbelt, Zaire[END_REF] to a remobilization during the Pan-African metamorphism, metasomatism and deformation between ca. 580 Ma and ca. 520 Ma (Barra et al., 2004;[START_REF] Brems | Metallogenesis of the Nkana copper-cobalt South Orebody, Zambia[END_REF][START_REF] Cailteux | Genesis of sediment-hosted stratiform copper-cobalt deposits, central African Copperbelt[END_REF]Cailteux et al., , 2007;;[START_REF] Dewaele | Multiphase origin of the Cu-Co ore deposits in the western part of the Lufilian fold-and-thrust belt, A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Katanga (Democratic Republic of Congo)[END_REF][START_REF] El Desouky | Two Cu-Co sulfide phases and contrasting fluid systems in the Katanga Copperbelt, Democratic Republic of Congo[END_REF][START_REF] Muchez | Factors controlling the precipitation of copper and cobalt minerals in sediment-hosted ore deposits: Advances and restrictions[END_REF][START_REF] Muchez | Diagenetic origin and multiphase modification of world-class Cu-Co deposits in the Central African Copperbelt[END_REF][START_REF] Nowecki | Tracing seawater evaporation and its role in the formation of sedimenthosted stratiform copper deposits[END_REF]Richards et al., 1988a, b;Selley et al., 2005;[START_REF] Steven | A metamorphosed Proterozoic carbonaceous shale-hosted Co-Ni-Cu deposit at Kalumbila, Kabompo Dome: The Copperbelt ore shale in northwestern Zambia[END_REF][START_REF] Sweeney | Some constraints on the formation of the Zambian Copperbelt deposits[END_REF].

In contrast, the mineralization of the Lumwana deposit, located in the Western Zambian Copperbelt (Mwombezhi Dome, Figs. 1 and3), is hosted by kyanite-micaschists, and its origin is debated. According to [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF] and [START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF], the kyanitemicaschists represent pre-Katanga gneiss attributed to the basement of the Katanga metasedimentary sequence, affected by pervasive metasomatic transformation coeval with the development of shear zones during the Pan-African orogeny. These authors propose a synmetamorphic remobilization of a pre-existing sulfide stock present in the gneissic protolith, but they do not provide geochronological constraints and do not specify the nature of the protolith of the micaschists (sedimentary or magmatic). [START_REF] Benham | Copper occurrences of the Mombezhi Dome Area, Northwestern Zambia[END_REF] proposed a

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metamorphosed lithologies; (ii) U-Th-Pb geochronological data on syn-to late-metamorphic monazite associated with Cu sulfides providing an age and a minimum constraint for the synmetamorphic Cu mineralization of Lumwana and (iii) a model for the Lumwana deposit integrating the Cu mineral system in the tectonic evolution of the Pan-African orogeny in this part of the Lufilian belt.

Regional geology

The Lufilian orogenic belt extends for 700 km from east to west and for 150 km from north to south (Fig. 1). From north to south (present-day coordinates), this belt is divided into: (i) the External fold-and-thrust belt (designated in the present study as the Congolese Copperbelt),

(ii) the Domes region (designated in the present study as the Zambian Copperbelt), (iii) the Synclinorial belt and (iv) the Katanga high [START_REF] De Swardt | Precambrian geology and structure in central Northern Rhodesia[END_REF][START_REF] Porada | Towards a new understanding of the Neoproterozoic-Early Palaezoic Lufilian and northern Zambezi Belts in Zambia and the democratic Republic of Congo[END_REF]. This orogenic belt is part of the Pan-African belts which formed during the Neoproterozoic and early Paleozoic as a result of the collision between the Congo and Kalahari cratons that led to the formation of West Gondwana [START_REF] Unrug | The Lufilian Arc: a microplate in the Pan-African collision zone of the Congo and the Kalahari cratons[END_REF][START_REF] Porada | Towards a new understanding of the Neoproterozoic-Early Palaezoic Lufilian and northern Zambezi Belts in Zambia and the democratic Republic of Congo[END_REF]John et al., 2004).

Pan-African orogeny

Breakup of the Rodinia supercontinent was initiated at ca. 880 Ma [START_REF] Hanson | Geologic evolution of the Neoproterozoic Zambezi Orogenic Belt in Zambia[END_REF][START_REF] Porada | Towards a new understanding of the Neoproterozoic-Early Palaezoic Lufilian and northern Zambezi Belts in Zambia and the democratic Republic of Congo[END_REF] as evidenced by the U-Pb ages obtained on magmatic zircon grains from the Kafue rhyolite and Nazingwe Formation volcanic rocks (880±12 Ma and 880±14 Ma respectively, Johnson et al., 2007) interpreted to record a period of continental rifting and opening of the Roan continental rift [START_REF] Hanson | Geologic evolution of the Neoproterozoic Zambezi Orogenic Belt in Zambia[END_REF][START_REF] Porada | Towards a new understanding of the Neoproterozoic-Early Palaezoic Lufilian and northern Zambezi Belts in Zambia and the democratic Republic of Congo[END_REF][START_REF] De Waele | Palaeoproterozoic to Neoproterozoic growth and evolution of the eastern Congo Craton: Its role in the Rodinia puzzle[END_REF]. The onset of the Lower Roan Group deposition occurred after intrusion, uplift and erosion of the youngest pre-Katanga intrusion in the Copperbelt basement, i.e. the calc-alkaline Nchanga granite, dated at 883±10 Ma (U-Pb on magmatic

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zircon, [START_REF] Armstrong | Geochronology of the Nchanga Granite, and constraints on the maximum age of the Katanga Supergroup, Zambian Copperbelt[END_REF], as suggested by the presence of detrital zircon grains dated at ca. 880 Ma in a Lower Roan quartzite (Fig. 2, [START_REF] Armstrong | Geochronology of the Nchanga Granite, and constraints on the maximum age of the Katanga Supergroup, Zambian Copperbelt[END_REF] and its unconformity on top of the Nchanga granite. However, the youngest concordant analysis provides an upper limit for the deposition of the siliciclastic Roan sequence at 840±13 Ma (Bartlett, pers. com.) in the Mwombezhi dome, Western Zambian Copperbelt.

FIGURE 2

A second rifting stage took place at ca. 750-720 Ma [START_REF] Eglinger | Cycle de l'uranium et évolution tectono-métamorphique de la ceinture orogénique Pan-Africaine du Lufilien (Zambie)[END_REF][START_REF] Key | The western arm of the Lufilian Arc in NW Zambia and its potential for copper mineralization[END_REF] as indicated by the U-Pb ages obtained on magmatic zircon from lavas of the Mwashya Subgroup (Fig. 2, [START_REF] Key | The western arm of the Lufilian Arc in NW Zambia and its potential for copper mineralization[END_REF], and by U-Pb on zircon from meta-diorite intrusive within the Katanga sequence [START_REF] Eglinger | Cycle de l'uranium et évolution tectono-métamorphique de la ceinture orogénique Pan-Africaine du Lufilien (Zambie)[END_REF]. This rifting stage led to the formation of an oceanic basin, at least in the Zambezi belt.

Subduction of the Zambezi ocean occurred between ca. 660-610 Ma (John et al., 2003) as recorded by eclogitic boudins (witness of the subduction phase between the Kalahari craton over-riding the Congo craton, John et al., 2003John et al., , 2004) ) within the Katanga sequence in the Zambezi belt, dated by a whole rock and garnet Lu-Hf isochron (John et al., 2004). The peak of metamorphism reached during continental collision is constrained by syn-metamorphic monazites from talc-kyanite-micaschists, described as whiteschists by [START_REF] Meneghel | The occurrence of uranium in the Katanga System of northwestern Zambia[END_REF]. The syn-metamorphic monazites are dated between ca. 550 Ma and 530 Ma, obtained by U-Th-Pb dating (Eglinger et al., 2014b, accepted) and U-Pb dating (John et al., 2004). The P-T constraints of these whiteschists are estimated at 13±1 kbar and 750±25°C [START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF]John et al., 2004).

Exhumation of these metamorphic rocks is evidenced by decompression and cooling recorded between ca. 510 and 470 Ma by Rb-Sr and K-Ar dating on biotite and muscovite from the basement and/or the metasedimentary cover [START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF]John et al., 2004). In

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the Solwezi dome, monazite grains associated with the retrogression paragenesis of the kyanite-micaschists yield U-Th-Pb ages at ca. 510-500 Ma (Eglinger et al., 2014b, accepted).

Metamorphic facies distribution

In the Congolese and Eastern Zambian Copperbelts, most, if not all (exception is e.g. Samba, Selley et al., 2005), of the deposits are hosted within the Lower Roan Group (<880 to ca. 790

Ma, Fig. 2, Selley, unpublished data in [START_REF] Hitzman | Formation of Sedimentary Rock-Hosted Stratiform Copper Deposits through Earth History[END_REF], more precisely in the Mines Subgroup (Congolese Copperbelt)/Kitwe Subgroup (Zambian Copperbelt) (Fig. 2, Selley et al., 2005). A similar metasedimentary sequence is exposed in the Western Zambian

Copperbelt, but this sequence was affected by higher P-T metamorphic conditions during the Pan-African orogeny. The metamorphic grade increases from prehnite-pumpellyite/lower greenschist facies in the Congolese Copperbelt (Fig. 1), to upper greenschist facies in the Eastern Zambian Copperbelt (Fig. 1) and to upper amphibolite facies in the Western Zambian Copperbelt (Fig. 1, Bernau, 2007;[START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF][START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF][START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript | Tectono-metamorphic evolution of the internal zone of the Pan-African Lufilian orogenic belt (Zambia): Implications for crustal reworking and syn-orogenic uranium mineralizations[END_REF][START_REF] Nowecki | Tracing seawater evaporation and its role in the formation of sedimenthosted stratiform copper deposits[END_REF][START_REF] Steven | A metamorphosed Proterozoic carbonaceous shale-hosted Co-Ni-Cu deposit at Kalumbila, Kabompo Dome: The Copperbelt ore shale in northwestern Zambia[END_REF][START_REF] Torremans | Remobilisation features and structural control on ore grade distribution at the Konkola stratiform Cu-Co ore deposit, Zambia[END_REF].

Mwombezhi dome lithotectonic units and structures

The Zambian Copperbelt comprises a complexly folded nappe pile composed of Neoproterozoic metasediments and migmatitic gneisses. The latter structures are interpreted as basement cored nappes [START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF]John et al., 2004). The Mwombezhi dome's core is composed of migmatitic granitic gneisses comprising (i) metatexitic paragneisses and orthogneisses, and (ii) enclaves and boudins of garnet-bearing amphibolite (Figs. 2 and4; Eglinger et al., accepted). These are interpreted as representing pre-Katanga basement [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF][START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF][START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF][START_REF] Eglinger | Cycle de l'uranium et évolution tectono-métamorphique de la ceinture orogénique Pan-Africaine du Lufilien (Zambie)[END_REF]John et al., 2004). These units are separated from the surrounding metasediments by a kyanite-micaschists layer

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representing a major shear zone (Fig. 3;[START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF][START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF][START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF][START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript | Tectono-metamorphic evolution of the internal zone of the Pan-African Lufilian orogenic belt (Zambia): Implications for crustal reworking and syn-orogenic uranium mineralizations[END_REF]John et al., 2004).

FIGURE 3

Cu mineralization

This section presents the different stages of remobilization during the Lufilian orogenic cycle of the sediment-hosted Cu mineralization, based on the textures and ages published in the literature.

Early-to intermediate-diagenetic Cu-mineralization

The Congolese and Eastern Zambian Copperbelts present framboidal pyrite and Cu sulfides attributed to an early-to intermediate-diagenetic (up to 180°C) Cu-mineralization stage [START_REF] Brems | Metallogenesis of the Nkana copper-cobalt South Orebody, Zambia[END_REF][START_REF] Cailteux | Genesis of sediment-hosted stratiform copper-cobalt deposits, central African Copperbelt[END_REF]Cailteux et al., , 2007;;[START_REF] Dewaele | Multiphase origin of the Cu-Co ore deposits in the western part of the Lufilian fold-and-thrust belt, A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Katanga (Democratic Republic of Congo)[END_REF][START_REF] El Desouky | Two Cu-Co sulfide phases and contrasting fluid systems in the Katanga Copperbelt, Democratic Republic of Congo[END_REF][START_REF] Muchez | Diagenetic origin and multiphase modification of world-class Cu-Co deposits in the Central African Copperbelt[END_REF]Richards et al., 1988a, b;Selley et al., 2005;[START_REF] Steven | A metamorphosed Proterozoic carbonaceous shale-hosted Co-Ni-Cu deposit at Kalumbila, Kabompo Dome: The Copperbelt ore shale in northwestern Zambia[END_REF][START_REF] Sweeney | Some constraints on the formation of the Zambian Copperbelt deposits[END_REF]. Sulfide crystallization is interpreted to be related to circulation of hydrothermal fluids during diagenesis and sulfur is assumed to result from bacterial sulfate reduction processes [START_REF] El Desouky | Two Cu-Co sulfide phases and contrasting fluid systems in the Katanga Copperbelt, Democratic Republic of Congo[END_REF][START_REF] Muchez | Anhydrite pseudomorphs and the origin of stratiform Cu-Co ores in the Katangan Copperbelt (Democratic Republic of Congo)[END_REF]. This hydrothermal diagenetic mineralization forms stratiform orebodies in siliciclastic or dolomitized metasedimentary rocks [START_REF] Batumike | Lithostratigraphy, basin development, base metal deposits, and regional correlations of the Neoproterozoic Nguba and Kundelungu rock successions, central African Copperbelt[END_REF][START_REF] Cailteux | Genesis of sediment-hosted stratiform copper-cobalt deposits, central African Copperbelt[END_REF][START_REF] Dewaele | Multiphase origin of the Cu-Co ore deposits in the western part of the Lufilian fold-and-thrust belt, A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Katanga (Democratic Republic of Congo)[END_REF]. This mineralization stage is dated at:

-816±62 Ma by Re-Os dating on diagenetic chalcopyrite and bornite from Konkola (Eastern Zambian Copperbelt, Fig. 1, Barra and Broughton, unpublished data, in Selley et al., 2005);

-788±24 Ma by Re-Os dating on nodules or disseminated bornite from the Mines Subgroup (Fig. 2, [START_REF] Muchez | Anhydrite pseudomorphs and the origin of stratiform Cu-Co ores in the Katangan Copperbelt (Democratic Republic of Congo)[END_REF][START_REF] Muchez | Diagenetic origin and multiphase modification of world-class Cu-Co deposits in the Central African Copperbelt[END_REF] in Kamoto dolomite, dolomitic siltstone

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and shale, and silicified dolomite [START_REF] Cailteux | Genesis of sediment-hosted stratiform copper-cobalt deposits, central African Copperbelt[END_REF] (north of the Kabompo dome, Fig. 1);

-645±15 Ma by Pb-Pb dating on Cu-Fe sulfides [START_REF] Richards | Pb isotope constraints on the age of sulfide ore deposition and U-Pb age of late uraninite veining at the Musoshi stratiform copper deposit, Central Africa Copperbelt, Zaire[END_REF] in Musoshi ore shale (Eastern Zambian Copperbelt, Fig. 1).

These ages point to Cu-deposition between ca. 800-650 Ma, most probably around ca. 800 Ma as suggested by Re-Os ages, though it is not possible to argue whether this occurred in a single well-defined event or during a more prolonged episode [START_REF] Muchez | Diagenetic origin and multiphase modification of world-class Cu-Co deposits in the Central African Copperbelt[END_REF][START_REF] Torremans | Remobilisation features and structural control on ore grade distribution at the Konkola stratiform Cu-Co ore deposit, Zambia[END_REF].

Syn-metamorphic Cu-remobilization and mineralization

This stock of diagenetic sulfides (pyrite and Cu sulfides) is assumed (i) to be a major source for sulfur [START_REF] Brems | Metallogenesis of the Nkana copper-cobalt South Orebody, Zambia[END_REF]; and (ii) to have been replaced by Cu sulfides (chalcopyrite, bornite, digenite and chalcocite) during a syn-orogenic stage (≥200°C up to ca. 450°C) [START_REF] Brems | Metallogenesis of the Nkana copper-cobalt South Orebody, Zambia[END_REF][START_REF] Cailteux | Genesis of sediment-hosted stratiform copper-cobalt deposits, central African Copperbelt[END_REF]Cailteux et al., , 2007;;[START_REF] Dewaele | Multiphase origin of the Cu-Co ore deposits in the western part of the Lufilian fold-and-thrust belt, A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Katanga (Democratic Republic of Congo)[END_REF][START_REF] El Desouky | Two Cu-Co sulfide phases and contrasting fluid systems in the Katanga Copperbelt, Democratic Republic of Congo[END_REF][START_REF] Muchez | Diagenetic origin and multiphase modification of world-class Cu-Co deposits in the Central African Copperbelt[END_REF][START_REF] Muchez | Factors controlling the precipitation of copper and cobalt minerals in sediment-hosted ore deposits: Advances and restrictions[END_REF]Richards et al., 1988a, b;Selley et al., 2005;[START_REF] Steven | A metamorphosed Proterozoic carbonaceous shale-hosted Co-Ni-Cu deposit at Kalumbila, Kabompo Dome: The Copperbelt ore shale in northwestern Zambia[END_REF][START_REF] Sweeney | Some constraints on the formation of the Zambian Copperbelt deposits[END_REF]. This mineralizing stage is evidenced in several Cu deposits such as Nkana-Mindola, Chibuluma West and Nchanga (Eastern Zambian Copperbelt, Fig. 1) where veinlets of bornite and chalcopyrite are hosted by argillite±arenite metamorphosed in the greenschist facies and dated at 583±24 Ma by Re-Os dating on chalcopyrite and bornite or carrollite [START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript | Multi-Stage mineralization in the Zambian Copperbelt based on Re-Os isotope constraints[END_REF]Selley et al., 2005).

Molybdenite from Nkana-Mindola yields an age of 525.7±3.4 Ma by Re-Os dating (Barra et al., 2004, Fig. 1), which is consistent with the peak of metamorphism recorded in the kyanitemicaschists at ca. 550-530 Ma [START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript | Tectono-metamorphic evolution of the internal zone of the Pan-African Lufilian orogenic belt (Zambia): Implications for crustal reworking and syn-orogenic uranium mineralizations[END_REF]John et al., 2004). In the Western Zambian Copperbelt (P-T metamorphic facies up to upper amphibolite facies, [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF][START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF][START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF][START_REF] Eglinger | Geochemical signatures of uranium oxides in the Lufilian belt: From unconformity-related to synmetamorphic uranium deposits during the Pan-African orogenic cycle[END_REF]John et al., 2004; Steven and [START_REF] Nowecki | Tracing seawater evaporation and its role in the formation of sedimenthosted stratiform copper deposits[END_REF]. These ages are interpreted by the author as dating Cu mineralization synchronous with the peak of metamorphism, even though the link between the dated samples and Cu sulfides from the kyanite-micaschists is not documented. Thus, in order to constrain the timing of syn-metamorphic Cu mineralization of the Western Zambian Copperbelt, it is required to bring new geochronological data.

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The syn-metamorphic remobilization and ore crystallization are interpreted to be related to the circulation of metamorphic metals-rich brines [START_REF] Cailteux | Genesis of sediment-hosted stratiform copper-cobalt deposits, central African Copperbelt[END_REF][START_REF] Dewaele | Multiphase origin of the Cu-Co ore deposits in the western part of the Lufilian fold-and-thrust belt, A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Katanga (Democratic Republic of Congo)[END_REF][START_REF] Eglinger | Uranium mobilization by fluids associated with Ca-Na metasomatism: A P-T-t record of fluid-rock interactions during Pan-African metamorphism (Western Zambian Copperbelt)[END_REF][START_REF] Mcgowan | Origin of the copper-cobalt deposits of the Zambian Copperbelt: An epigenetic view from Nchanga[END_REF][START_REF] Mcgowan | Origin of the Nchanga copper-cobalt deposits of the Zambian Copperbelt[END_REF]. Meta-evaporites from the Roan Group are invoked as a potential source of the salt for these fluids (Fig. 2, [START_REF] Cailteux | Genesis of sediment-hosted stratiform copper-cobalt deposits, central African Copperbelt[END_REF][START_REF] Eglinger | Geochemical signatures of uranium oxides in the Lufilian belt: From unconformity-related to synmetamorphic uranium deposits during the Pan-African orogenic cycle[END_REF]Eglinger et al., , 2014a, b;, b;[START_REF] El Desouky | Two Cu-Co sulfide phases and contrasting fluid systems in the Katanga Copperbelt, Democratic Republic of Congo[END_REF]Selley et al., 2005). This is consistent with the conclusions of [START_REF] Mcgowan | Origin of the copper-cobalt deposits of the Zambian Copperbelt: An epigenetic view from Nchanga[END_REF][START_REF] Mcgowan | Origin of the Nchanga copper-cobalt deposits of the Zambian Copperbelt[END_REF] who proposed (i) a synorogenic circulation of metals transported by metals-and sulfates-bearing metamorphic fluids in Nchanga (Fig. 1) and (ii) the precipitation of sulfides related to the thermochemical sulfate reduction (TSR) of an ore-fluid, defined by the following reaction: CaSO 4 (anhydrite) + CH 4 (fluid) CaCO 3 (calcite) + H 2 S (fluid) + H 2 O (fluid) [START_REF] Cross | Rates and Mechanisms of Thermochemical Sulphate Reduction[END_REF][START_REF] Mcgowan | Origin of the copper-cobalt deposits of the Zambian Copperbelt: An epigenetic view from Nchanga[END_REF].

This reaction requires an electron provider for the oxidation of sulfates during the redox process [START_REF] Machel | Bacterial and thermochemical sulfate reduction in diagenetic settingsold and new insights[END_REF] which could be the organic matter initially present in the sediments.

Late-deformation Cu-remobilization and mineralization

In the Zambian Copperbelt, some Cu mineralization postdate the peak of metamorphism, i.e.

are significantly younger than ca. 530 Ma (John et al., 2004;[START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript | Tectono-metamorphic evolution of the internal zone of the Pan-African Lufilian orogenic belt (Zambia): Implications for crustal reworking and syn-orogenic uranium mineralizations[END_REF], and are thus related to the final stages of the tectonic evolution of the Lufilian belt (Brems et al.,

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2009; Richards et al., 1998b;Selley et al., 2005;[START_REF] Torrealday | Re-Os and U-Pb dating of the vein-hosted mineralization at the Kansanshi copper deposit, Northern Zambia[END_REF]. The Musoshi mineralization (Fig. 1), dated at 645±15 Ma (Richards et al., 1988a[START_REF] Richards | Pb isotope constraints on the age of sulfide ore deposition and U-Pb age of late uraninite veining at the Musoshi stratiform copper deposit, Central Africa Copperbelt, Zaire[END_REF]Selley et al., 2005), has been remobilized by hydrothermal fluids that lead to the formation of Cu-rich veins, and dated at 514±2 Ma by U-Pb on rutile (Richards et al., 1988a) and at 514±3 Ma by U-Pb on uraninite [START_REF] Richards | Pb isotope constraints on the age of sulfide ore deposition and U-Pb age of late uraninite veining at the Musoshi stratiform copper deposit, Central Africa Copperbelt, Zaire[END_REF]. The Kansanshi deposit (Fig. 1) presents two generations of veins crosscutting the Katanga metasedimentary cover dated at: (i) 511.8±1.7

Ma and 512.9±1.7 Ma (first generation), and (ii) 503.0±1.7 Ma and 501.8±1.7 Ma (second generation) by Re-Os dating on molybdenite [START_REF] Torrealday | Re-Os and U-Pb dating of the vein-hosted mineralization at the Kansanshi copper deposit, Northern Zambia[END_REF].

Sampling and analytical methods

Sampling of the micaschists

The present study focuses on the Lumwana deposit, located in the Western Zambian

Copperbelt of the Lufilian belt and more precisely on the Mwombezhi Dome (Fig. 3). The CHI0999 drill-hole (East: 379109.8; North: 8641615; Elevation: 1355.413) from Chimiwungo (Barrick Ltd. prospect) was sampled (Fig. 4) and complemented by field investigations in the Mwombezhi dome area (Figs. 1 and3) in April 2012. This drill-hole is representative of the mineralogy and microstructures developed in the Lumwana deposit and the chosen samples are similar to the ones investigated at the deposit scale in studies of [START_REF] Benham | Copper occurrences of the Mombezhi Dome Area, Northwestern Zambia[END_REF], [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF], [START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF] and [START_REF] Nowecki | Tracing seawater evaporation and its role in the formation of sedimenthosted stratiform copper deposits[END_REF]. The drill-hole is located in the southern limb of the Mwombezhi dome and is plunging 80 degrees towards the north. It comprises gneisses alternating with garnet-or kyanite-micaschists bearing Cu(-U) (Fig. 5). Three samples representative of the variety of the micaschists have been studied in detail. For each sample, the depth is indicated after the name of the drill-core (e.g.:

CHI0999#88 for 88 meters depth). One sample contains garnet but no kyanite nor Cu (CHI0999#88-13, Fig. 5); two samples do not contain garnet but bear kyanite and large Cu

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sulfides aggregates (CHI0999#89-16 and 93-17, Fig. 5). Sulfide assemblages differ from the top of the drill-core to the bottom. In the upper part, chalcopyrite is associated with pyrrhotite (CHI0999#89-16-a & 16-b, Fig. 5) while chalcopyrite is found together with bornite in the lower part (CHI0999#93-17-a & 17-b, Fig. 5).

FIGURE 4

The following analytical techniques were applied on grains positioned relative to the microstructure of the Cu-rich micaschists, i.e. the kyanite-micaschists, and on barren garnetmicaschists in order to constrain the different metamorphic and deformation stages recorded by these rocks.

Electron Microprobe

Major elements were identified by the Electron Microprobe (EMP) method using a Cameca computer-controlled SX-100 (GeoRessources, Nancy). For silicates, the accelerating voltage was set at 15 kV, beam current at 12 nA and peak counting time varied from 10 to 20 s. For quantitative analyzes of monazite, the major and traces elements (P, Si, Ca, Y, La, Ce, Pr, Nd, Sm, Gd, Pb, Th, U) have been measured using an accelerating voltage of 20 kV, beam current was set to 100 nA. Peak counting time was set to 120 s for Pb, 100 s for U and 20 s for the others elements.

Laser Ablation-Inductively

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During the course of an analysis, the signals of 204 (Pb+Hg), 206 Pb, 207 Pb, 208 Pb and 238 U masses are acquired. No common Pb correction was applied owing to the large isobaric interference with Hg. The 235 U signal is calculated from 238 U on the basis of the ratio 238 U/ 235 U=137.88. Single analyzes consisted of 20 s of background integration followed by 60 s integration with the laser firing and then a 10 s delay to wash out the previous sample. For more information on the settings of the instrument, see [START_REF] Ballouard | Tectonic record, magmatic history and hydrothermal alteration in the Hercynian Guérande leucogranite[END_REF]. Spot diameters of 15 μm associated with repetition rates of 3 Hz with a laser fluency of 7.3 J.cm -2 were used during the present study. Data were corrected for U-Pb and U-Th-Pb fractionation and for the mass bias by standard bracketing with repeated measurements of the Moacir monazite standard [START_REF] Gasquet | Miocene to Messinian deformation and hydrothermal activity in a pre-Alpine basement massif of the French western Alps: new U-U-Th-Pb and argon ages from the Lauzière massif[END_REF] quadrupole ICP-MS. The LA-ICP-MS system was optimized to have the highest sensitivity for all elements (from 7 Li to 238 U), ThO/Th ratio < 0.5% and Th/U ratio of 1. Samples were ablated with a 24 μm laser spot size, a fluence of 7.4 J.cm -2 and a pulse rate of 5 Hz. The

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ACCEPTED MANUSCRIPT carrier gas used was Helium (0.5 l/min) which was mixed with Argon (0.5 l/min) gas before entering the ICP-MS. The ICP-MS settings were the following: ICP RF Power at 1550 W, cooling gas (Ar) at 15 l/min, auxiliary gas (Ar) at 0.96 l/min and a dual detector mode was used. For each analysis, acquisition time was 30 s for background, 30 s for external standard (NIST 610) and between 15 to 30 s (75 to 150 laser pulses) for rutile mineral analysis depending on the size and thickness of each crystal. External standard used was NIST 610 silicate glass [START_REF] Pearce | A compilation of new and published major and trace element data for NIST SRM 610 and NIST SRM 612 glass reference materials[END_REF] for concentrations), and 47 Ti was used as internal standard.

Identified minerals were imaged and analyzed before LA-ICP-MS analyzes using a SEM (Hitachi S-4800) and an electron microprobe (Cameca computer-controlled SX-100, GeoRessources, Nancy, France) respectively. TiO 2 content was assumed to be 100 wt%.

Silicate glass NIST612 and rutile R10 [START_REF] Luvizotto | Rutile crystals as potential trace element and isotope mineral standards for microanalysis[END_REF] were used as cross-calibration samples and to certify the accuracy and precision of the measurements on the unknown rutiles. Acquisition times were: 0.01 s for 47 Ti, 0.02 s for 53 Cr, 93 Nb and 0.05 s for 90 Zr, 91 Zr.

Total cycle time was 367 ms. Data were treated with the "Iolite" software [START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript Paton | Iolite: freeware for the visualisation and processing of mass spectrometer data[END_REF].

Zr-in-rutile temperatures were calculated using the thermometer defined by Zack et al.

(2004a):

T (in °C) = 127.8×ln (Zr in ppm)-10

The uncertainty on the computation of temperatures using this thermometer is of ±50°C and is inherited from the temperature estimations of the natural samples used to calibrate this thermometer (Zack et al., 2004a). The concentration of Zr in rutile grains should be buffered by coexisting zircon and quartz phases (Zack et al., 2004a).

Petrographic and microstructural description of the micaschists

Lithologies

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The Lumwana micaschists typically comprise garnet-micaschists layers alternating with kyanite-micaschists at the scale of tens of centimeters (Fig. 5). The so-called "ore schists", correspond to the sulfide-rich kyanite-micaschists (pyrrhotite, chalcopyrite and bornite)

whereas the garnet-micaschists, kyanite-free, contain very little sulfides.

FIGURE 5

Metamorphic fabrics

The kyanite and garnet-micaschists show (i) the same grano-lepidoblastic texture and (ii) a superposition of structures associated with distinct mineral paragenesis attributed to three successive deformation stages, D 1 , D 2 , D 3 (Figs. 5,6,7 and 8).

FIGURE 6 FIGURE 7

D 1 deformation-metamorphic stage

The D 1 deformation and metamorphic stage is identified by the preservation of an S 0/1 foliation as relics in microlithons or as inclusions in some porphyroblasts. This foliation is delineated by (i) fine-grained layers of quartz (Qz 1 , Fig. 8a), plagioclase, rutile, alternating with mica-rich layers, (ii) rounded zircons and altered Co-Fe-Ni sulfides grains (Fig. 9a), (iii) quartz veins (Qz 2 ) transposed into the later S 2 schistosity (Figs. 6 and7) and locally containing pyrrhotite and (iv) a first generation of rounded kyanite poikiloblasts (Ky 1 , Fig. 8b) crystallized during late-D 1 deformation and containing oriented inclusions of graphite, rutile, bornite, chalcopyrite and digenite (Fig. 9b). These same oriented inclusions delineate the S 0/1 foliation in late-D 1 porphyroblasts of plagioclase (Figs. 6 and8c).

D 2 deformation-metamorphic stage

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A steep-dipping S 2 schistosity wraps late-D 1 plagioclase porphyroblasts (Fig. 8c), transposes D 1 metamorphic fabrics (Fig. 8a) and is expressed by the preferred orientation of the phlogopite and muscovite (001) cleavage planes. This S 2 schistosity is preserved in the least deformed zones of the kyanite-micaschists (e.g. sample CHI0999#89-16-b, Fig. 6) and is transposed in the later S 3 schistosity (e.g. sample CHI0999#93-17-a, Fig. 10a).

D 3 deformation-metamorphic stage

The main metamorphic fabric developed in Lumwana's kyanite-micaschists is a shallowdipping S 3 schistosity which is associated with top to the south kinematic criteria. This schistosity is delineated by the preferred orientation of the phlogopite and muscovite (001

)
cleavage planes alternating with quartz-rich layers (Fig. 7), forming the grano-lepidoblastic texture of the micaschists. This D 3 metamorphic event transposes previous fabrics and quartz veins (Qz 1 and Qz 2 , Fig. 7). It is in an axial planar position of F 3 chevron and isoclinal folds affecting the S 2 schistosity (sample CHI0999#89-16-b, Fig. 6). Phlogopite and muscovite wrap Ky 1 grains, and are parallel to the preferred orientation of a second generation of synkinematic kyanite porphyroblasts (Ky 2 , Fig. 8d) kinked and wrapped into the S 3 schistosity.

These features evidence their crystallization during the D 2 metamorphic stage and their transposition/recrystallization into the D 3 metamorphic fabric (Ky 2-3 , Fig. 8d). These Ky 2-3 porphyroblasts are associated with chalcopyrite, bornite, monazite and rutile which delineate this fabric. The D 3 deformation stage is ended by shallow-dipping top to the north C 3 shear zones (Figs. 5, 6 and 7) cross-cutting the S 3 schistosity (Fig. 7).

Petrography of the major metamorphic phases in micaschists

Muscovite and phlogopite define the matrix of the micaschists. Black micas grains are phlogopite with a mean X Mg value equal to 0.851 and 0.633 for pre-D 3 and syn-D 3 grains respectively (Table 2). There are two types of quartz veins transposed in the S 3 foliation (Figs.

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6, 7 and 8a). Qz 1 veins are dominated by quartz grains with a heterogeneous size but not exceeding a few micrometers in diameter, but also contain plagioclase and micas. Qz 2 veins are dominated by quartz grains with a much larger diameter (10 to several tens of micrometers wide), also contain plagioclase but no micas. They often contain sulfides such as chalcopyritepyrrhotite or bornite-chalcopyrite (Figs. 6 and7). Plagioclase grains from the matrix may contain elongated inclusions of micas and/or graphite defining an inherited S 0/1 foliation (Fig. 8c). Late-D 3 shear bands are associated with (i) the retrogression of phlogopite into chlorite (Fig. 8f), (ii) crystallization of tourmaline, rutile and pyrite and (iii) transposition of sulfides.

Alternating with these Cu-rich kyanite-micaschists, barren garnet-micaschists display the same textures and a similar mineralogy to the exception of the absence of kyanite and sulfides and the presence of garnet poikiloblasts with no pressure shadow. These poikiloblasts contain oriented inclusions of phlogopite, chlorite, plagioclase, quartz and rutile, mostly The first generation of sulfides predates the D 1 phase as indicated by a borniterich/chalcopyrite-poor assemblage (in the lower part of the drill-hole), locally associated with a few digenite grains, enclosed into Ky 1 (Fig. 9b), and chalcopyrite enclosed into late-D 1 porphyroblasts of plagioclase. Bornite and chalcopyrite may also be enclosed into Ky 2 . In addition to this paragenesis, chalcopyrite and pyrrhotite/bornite are also present in quartz veins (Qz 2 ) that are transposed into the S 2 and in the S 3 schistosities.

FIGURE 9

The The third generation of sulfides, and the best expressed, is associated with the development of the D 3 metamorphic fabrics (S 3 schistosity). A bornite-poor/chalcopyrite-rich assemblage is expressed in pressure shadows of Ky 1 in association with micas delineating the S 3 schistosity wrapped around Ky 1 porphyroclasts (Figs. 7 and8b). The same sulfides assemblage delineates the S 3 schistosity and is elongated parallel to the (001) cleavage plane of micas (Fig. 8d). Chalcopyrite and bornite are also cogenetic with Ky 2-3 porphyroblasts (Fig.

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Finally, the sulfides are locally transposed into C 3 shear bands indicating that they were remobilized and recrystallized during late-D 3 .

Monazite

Monazite grains are present in various textural positions, namely (i) delineating the S 2 schistosity in axial planar position of F 3 folds (Fig. 10a), (ii) within the S 3 schistosity (Fig. 10b), (iii) as inclusion in syn-S 3 Cu sulfides (Fig. 10c), and (iv) intergrown with syn-S 3 Cu sulfides (Fig. 10d). It is interesting to note that these monazite grains are not wrapped by micas delineating the S 3 schistosity but intergrown with them, and that these grains do not show any signs of a detrital origin (rounded shape or percussion marks).

FIGURE 10

Monazite grains associated with relics of the S 2 schistosity affected by F 3 folds are interpreted as having crystallized during the D 2 metamorphic event and as being partially transposed/recrystallized into the D 3 metamorphic fabrics. Chemical compositions of the representative monazite are reported in and ThO content variations. This is consistent with the brabantite substitution [START_REF] Rose | Brabantite, CaTh(PO4)2, a new mineral of the monazite group[END_REF], involving the reaction described by [START_REF] Poitrasson | Electron microprobe and LA-ICP-MS study of monazite hydrothermal alteration: Implications for U-Th-Pb geochronology and nuclear ceramics[END_REF]: 2REE 3+ Th 4+ + Ca 2+ (Fig. 13a; [START_REF] Spear | Apatite, Monazite, and Xenotime in Metamorphic Rocks[END_REF].

Rutile

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Rutile grains are present in all metamorphic paragenesis, namely (i) as inclusions in Ky 1 predating the D 1 deformation-metamorphic stage; (ii) coeval with garnet poikiloblasts (Fig. 11a); (iii) aligned along the (001) cleavage plane of micas delineating the S 3 schistosity and thus synchronous with the syn-D 3 Cu sulfides and Ky 2-3 porphyroblasts (Figs. 9d, 11b andc) and (iv) associated with sulfides in shear bands developed during late-D 3 metamorphic stage (Fig. 11d). However, pre-D 1 grains were not large enough to conduct LA-ICP-MS analyzes.

FIGURE 11

Rutile grains from garnet-micaschists (sample CHI0999#88-13) are chemically different than the ones from the kyanite-micaschists (Table 4) with (i) Cr from 329 to 526 ppm in the kyanite-micaschists and from 65 to 84 ppm in the garnet-micaschists, (ii) 90 Zr from 76 to 140 ppm in the kyanite-micaschists and from 59 to 74 ppm in the garnetmicaschists, (iii) 91 Zr from 77 to 142 ppm in the kyanite-micaschists and from 59 to 73 ppm in the garnet-micaschists and (iv) Nb from 3390 to 7300 ppm in the kyanite-micaschists and from 2400 to 5650 ppm in the garnet-micaschists. Results obtained for the Cr and Nb contents have been plotted in a Cr vs Nb diagram (Fig. 14a).

Other accessory minerals

Zircon grains are a few micrometers wide and are enclosed into the quartz-plagioclase matrix and/or into micas delineating the S 0/1 foliation and the S 2 and S 3 schistosities. Graphite flakes delineate S 2 (Fig. 8e) and S 3 schistosities and are present as inclusions in both generation of kyanite (Ky 1 and Ky 2-3 ) porphyroblasts. A few apatite grains are in textural equilibrium with the syn-D 2 chalcopyrite-pyrrhotite assemblage. Retrograde chlorite (partial alteration of phlogopite, Fig. 8f) is also present in garnet poikiloblasts.

In addition to the main sulfide assemblages, a few grains of Co-Fe-Ni sulfides are also present and show rounded shapes and evidence of alteration (Figs. 9a andc). Similarly, a few

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sphalerite grains are present as inclusions in the Cu sulfides (Fig. 9e). Uranium is expressed in the kyanite-micaschists as uraninite grains which, according to their microstructural position and shape, pre-date small euhedral pyrite grains. Uraninite may also be associated with molybdenite which delineates the S 3 schistosity (Fig. 9f).

According to these microstructural and petrographic observations, the three different deformations and metamorphic stages are summarized in the paragenetic sequence proposed in Fig. 12.

FIGURE 12

Geochronological and thermometric constraints

In this section, we provide new geochronological and thermometric constraints for the metamorphic deformation stages that have been defined in the previous sections.

U-Th-Pb dating on syn-to late-metamorphic monazite

In monazite, 206 Pb and 208 Pb are the most abundant Pb isotopes. In addition, monazite grains from Lumwana's micaschists present a non-negligible substitution to brabantite (Fig. 13a, [START_REF] Poitrasson | Electron microprobe and LA-ICP-MS study of monazite hydrothermal alteration: Implications for U-Th-Pb geochronology and nuclear ceramics[END_REF][START_REF] Rose | Brabantite, CaTh(PO4)2, a new mineral of the monazite group[END_REF] schistosity. These syn-D 2-3 monazite grains display apparent 208 Pb/ 232 Th dates ranging from 537.1±6.6 to 502.8±6.3 Ma (Table 1). The scattering in the ages (Fig. 13c) tends to show differences between the different crystals and is interpreted to record a continuum of crystallization from ca. 540 Ma down to ca. 500 Ma.

FIGURE 13

Thermometric constraints on the metamorphic path

Even though three generations of rutile are represented in our samples, pre-D 1 grains were not large enough to conduct Zr-in-rutile thermometry analyzes. Two populations of rutile grains have thus been investigated in order to constrain the temperature reached during these metamorphic stages: (i) rutile grains delineating the S 3 schistosity (parallel to muscovite and phlogopite (001) cleavage planes) and (ii) rutile grains associated with late-D 3 shear bands, using the Zack et al. (2004a) thermometer which is based on the concentration of Zr in rutile.

In addition, as the temperature depends on the concentration of Zr in the matrix (Zack et al., 2004a), we choose to limit our temperature computations to rocks with a similar mineralogy and thus an identical chemical composition, i.e. only in kyanite-micaschists where zircon and quartz are coexisting phases and not in garnet-micaschists in which no zircon grains are observed associated with rutile grains. Indeed, in the latter, the lack of zircon grains is possibly leading to a buffering of Zr content in the minerals inducing an underestimation of temperatures. Two zirconium isotopes ( 90 Zr and 91 Zr) have been analyzed. Their respective Zr concentrations in the ablated grains are similar within error. The differences between the two isotopes concentrations for a same ablation spot range from 0 to ca. 4%. This difference of concentration leads to a difference in the computation of the temperature ranging from 0 to 0.99%. Considering the uncertainty of the thermometer which was estimated by Zack et al.

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(2004a) at ±50°C, we assume that using the concentration of one isotope or the other does not affect significantly the results. Thus, computation of temperatures is based on the most abundant zirconium isotope content: 90 Zr.

Crystallization temperatures of rutile grains from kyanite-micaschists (samples CHI0999#93-17-a and -b) from the two different generations are reported in Fig. 14b and Table 5. Rutile associated with the S 3 schistosity display temperatures ranging from 580 to 620±50°C (Syn-D 2-3 , Fig. 14b). Rutile grains associated with sulfides and shear bands marking late-D 3 metamorphic stage display temperatures ranging from 540 to 610±50°C (Late-D 3 , Fig. 14b).

FIGURE 14

In addition, thermometric constraint was obtained in garnet-micaschists by garnetphlogopite (Grt-Phl) thermometry based on Fe-Mg contents of crystal rims along garnetphlogopite grain contacts (Holdaway, 2000). In the Lumwana's micaschists phlogopite delineating the S 3 schistosity in textural equilibrium with garnet poikiloblasts record temperatures ranging from 630 to 635±25°C (Table 6) at 6 kbar (minimum pressure recorded for D 3 metamorphic stage by Eglinger et al., accepted). Temperatures computed for 9 and 12 kbar are similar to the ones obtained for 6 kbar (temperature differences do not exceed 3°C, Table 6).

Discussion

Metamorphic evolution recorded by the Lumwana micaschists

Results from the present study and data from literature are summarized in a P-T diagram in which the evolution of the microstructures and paragenesis of the Lumwana's Cu-rich kyanite-micaschists are reported (Fig. 15).

A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

In the present study, we have identified three deformation stages marked by distinct mineral assemblages and microstructures. The first deformation stage, D 1 , marked by Ky 1 poikiloblasts containing a relictual S 0/1 foliation delineated by oriented mineral inclusions of micas, graphite and Cu-sulfides (a bornite-rich/chalcopyrite-poor assemblage), is interpreted to represent the metamorphic paragenesis developed during the prograde part of the P-T path.

The metamorphic peak assemblage characterized by a Ky 1 and graphite assemblage, records HP-MT conditions (D 1 deformation-metamorphic stage, Fig. 15) as proposed by Eglinger et al. (accepted) and John et al. (2004). This HP-MT D 1 event is attributed to burial down to 40-50 km under a geothermal gradient of 15-20°C.km -1 related to subduction of the continental margin of the Congo craton at ca. 550-530 Ma (John et al., 2004;[START_REF] Eglinger | Uranium mobilization by fluids associated with Ca-Na metasomatism: A P-T-t record of fluid-rock interactions during Pan-African metamorphism (Western Zambian Copperbelt)[END_REF] followed by the collision of the Congo and Kalahari cratons (John et al., 2004;[START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript | Tectono-metamorphic evolution of the internal zone of the Pan-African Lufilian orogenic belt (Zambia): Implications for crustal reworking and syn-orogenic uranium mineralizations[END_REF]. In the Solwezi region, kilometer-scale isoclinal folds might be attributed to this D 1 phase [START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF][START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript | Tectono-metamorphic evolution of the internal zone of the Pan-African Lufilian orogenic belt (Zambia): Implications for crustal reworking and syn-orogenic uranium mineralizations[END_REF].

The second deformation stage, D 2 , is marked by a steep-dipping schistosity S 2 , delineated by the preferred orientation of phlogopite and muscovite (001) cleavage planes wrapped around late-D 1 porphyroblasts of plagioclase. At the regional scale, in the Solwezi region, the F 1 isoclinal folds are refolded by asymmetric F 2 folds resulting with hook-type interferences consistent with a top-to-the south sense of shear [START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF][START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript | Tectono-metamorphic evolution of the internal zone of the Pan-African Lufilian orogenic belt (Zambia): Implications for crustal reworking and syn-orogenic uranium mineralizations[END_REF]. The S 2 schistosity also includes a second generation of Cu sulfides 5). No monazite grains crystallized during this late deformation stage, which is interpreted as postdating these minerals. We thus propose that the late-D 3 fabric development is younger than ca. 500 Ma, the youngest U-Th-Pb age obtained on monazite. This is in good agreement with the onset of cooling of the metamorphosed rocks reported in the literature which constrain this stage between ca. 500 and 470 Ma (Rb-Sr isotopic ages on muscovite and biotite; see section 2.1 for details, [START_REF] Cosi | Late Proterozoic thrust tectonics, high-pressure metamorphism and uranium mineralization in the Domes Area, Lufilian Arc, northwestern Zambia[END_REF]John et al., 2004).

Successive syn-metamorphic remobilization of Lumwana's mineralization during

Pan-African orogeny

In micaschists from Chimiwungo, pyrrhotite and bornite grains are not present in the same sections of the studied micaschists. The lower part of the drill core presents bornite associated with chalcopyrite grains whereas the upper part contains a chalcopyrite-pyrrhotite(±pyrite) assemblage. These two assemblages are mutually exclusive as described by [START_REF] Benham | Copper occurrences of the Mombezhi Dome Area, Northwestern Zambia[END_REF], [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF] and [START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF].

In the present study, we identified three Cu sulfide generations in kyanite-micaschists from Chimiwungo that are interpreted as being related to distinct mineralizing events. The first generation of sulfides is represented as chalcopyrite-pyrrhotite or chalcopyrite-bornite (a bornite-rich/chalcopyrite-poor assemblage) as inclusions into Ky 1 (Fig. 8b). This is consistent with the observations of [START_REF] Benham | Copper occurrences of the Mombezhi Dome Area, Northwestern Zambia[END_REF], [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF] The third and final generation of sulfides described in the present study is coeval with the kinking and partial recrystallization of a second generation of kyanite (Ky 2-3 ) marking the third metamorphic assemblage identified, corresponding to the retrograde part of the P-T path (D 3 metamorphic event). In addition, Cu sulfides (a bornite-poor/chalcopyrite-rich assemblage) are expressed as pressure shadows around Ky 1 grains, which are porphyroclasts wrapped in the S 3 schistosity. In some cases, these sulfides may fill fractures present in Ky 1 (Fig. 7), but are not fully enclosed into the aluminosilicates. [START_REF] Benham | Copper occurrences of the Mombezhi Dome Area, Northwestern Zambia[END_REF], [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF] and [START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF] described a local remobilization of sulfides during metamorphism, with no addition of copper, as chalcopyrite and bornite can be found in pressure shadows of kyanite porphyroblasts. However, these authors considered only one generation of kyanite around which pressure shadows contain Cu sulfides. In addition, they do not specify if the presence of Cu is related to diagenetic or hydrothermal processes [START_REF] Benham | Copper occurrences of the Mombezhi Dome Area, Northwestern Zambia[END_REF][START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF][START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF].

Textural evidence show that Ky 1 porphyroblasts first crystallized during the development of the S 0/1 foliation (D 1 deformation-metamorphic stage, Fig. 15) as a witness of the metamorphic peak and were fractured during the development of the retrograde S 3 schistosity (D 3 deformation-metamorphic stage), before being filled in by Cu sulfides (Fig. 7).

A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

In these pressure shadows (sample CHI0999#93-17-b), monazite grains are enclosed or cogenetic to the sulfide assemblage and to the S 3 schistosity. Monazite fully enclosed in the syn-D 3 sulfide assemblage displays 208 Pb/ 232 Th ages ranging from 525.8±6.8 Ma to 511.2±6.6 Ma (Fig. 10c, Table 1). These ages are bracketed into the time period recorded by the other

ACCEPTED MANUSCRIPT

Mitukuluku, Eglinger et al., 2014a). The fluid salinities are 53-59 mass% of CaCl 2 and 13-15 mass% of NaCl (Eglinger et al., 2014a). These authors propose that the high salinity of this mineralizing fluid is related to the dissolution of evaporites from the Lower Roan Group described in the Katanga sequence (Fig. 2). Moreover, the textural position of ore minerals at Accordingly the last remobilization of sulfides occurred during post-orogenic gravitational collapse and is younger than ca. 500 Ma (Fig. 15).

The correlation between mineralization and metamorphism leads to an assessment of the role of metamorphism in terms of concentration or dispersion of Cu. The mineralized paragenesis of the Lumwana's kyanite-micaschists during the Pan-African orogeny evolves from a bornite-rich (Cu 5 FeS 4 )/chalcopyrite-poor (CuFeS 2 ) assemblage inherited from the sedimentary protolith to a syn-metamorphic bornite-poor/chalcopyrite-rich assemblage developed during syn-and post-orogenic exhumation. This tends to show that the proportional abundance of Cu decreases (and Fe increases conversely) during metamorphism. This suggests that metamorphism may have a dispersive effect on Cu mineralization.

FIGURE 15

Nature of the protolith of the Lumwana micaschists

Micaschists from Chimiwungo display noticeable chemical variations. Indeed, within ten centimeters, the petrography varies from a kyanite-and sulfide-free garnet-rich micaschists to a garnet-free kyanite-and Cu-rich micaschists (Fig. 5). The mutual exclusivity of kyanite and garnet that both indicate the pressure conditions recorded by the samples, and the association of kyanite with the mineralization, may be related to a chemical difference inherited from the metasedimentary protolith. In addition, different generations of rutile have been identified which is consistent with a pre-metamorphic lithological compositional layering inherited from the sedimentary sequence. Furthermore, rounded zircon grains, enclosed into the quartzplagioclase matrix and in micas delineating the S 1 , S 2 and S 3 schistosities, suggest that they represent detrital grains inherited from a sedimentary protolith (Fig. 12). Similarly, Co-Fe-Ni sulfides grains show rounded shapes and evidence of alteration (Fig. 9a), consistent with a detrital origin. The most probable explanation for the presence of Ni in the system is that Co-Fe-Ni sulfides grains are detrital and come from the erosion of mafic intrusive bodies emplaced before the Pan-African orogeny. Some amphibolite boudins contained in the Chimiwungo hangingwall schist and in the core of the Mwombezhi dome (Fig. 4) display Nd model ages, relative to the Depleted Mantle (T DM ) ranging from 2.93 to 2.32 Ga [START_REF] Eglinger | Cycle de l'uranium et évolution tectono-métamorphique de la ceinture orogénique Pan-Africaine du Lufilien (Zambie)[END_REF]. They represent good candidates for the source of Ni.

Carbonaceous material is represented in the micaschists as graphite. This mineral may be hydrothermal or metamorphic in origin. The latter case implies that graphite crystallizes from organic matter during the prograde part of the P-T path and/or at the peak of metamorphism. Because graphite from the Chimiwungo micaschists is not associated with veins, suggesting a hydrothermal activity, we conclude that it probably has a metamorphic origin and records the D 1 peak of metamorphism. This is consistent with the elongation of graphite parallel to the (001) cleavage plane of the micas (Figs. 8e and11b). Inclusions of graphite in Ky 1 evidence the presence of carbonaceous material in the protolith of the micaschists, before burial, i.e. before the D 1 metamorphic stage. All these arguments indicate that the protolith of the mineralized host rock at Lumwana (i.e. micaschists) is sedimentary, which is consistent with the proposition of [START_REF] Benham | Copper occurrences of the Mombezhi Dome Area, Northwestern Zambia[END_REF], and which complements the conclusions of [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF] and [START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF]. Indeed, for the Lumwana Cu deposit, [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF] and [START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF] Even though an in-situ remobilization of Cu-sulfides during metamorphism with no addition of Cu is proposed by [START_REF] Benham | Copper occurrences of the Mombezhi Dome Area, Northwestern Zambia[END_REF], [START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF] and [START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF], we cannot bring any evidence to exclude a new input of metals during the Lufilian orogeny.

Accordingly, the data presented in this paper on the Lumwana Cu deposit (Western Zambian Copperbelt) are consistent with a Cu deposit formed by (i) a primary mineralization

Conclusion

In [START_REF] Zack | Rutile geochemistry and its potential use in quantitative provenance studies[END_REF][START_REF] Triebold | Deducing source rock lithology from detrital rutile geochemistry: An example from the Erzgebirge, Germany[END_REF][START_REF] A C C E P T E D M A N U S C R I P T Accepted Manuscript Meinhold | Rutile chemistry and thermometry as provenance indicator: An example from Chios Island, Greece[END_REF]; b: rutile crystallization temperature obtained using Zr-in-rutile thermometry defined by Zack et al. (2004a). Analyzes are reported in Table 4. Abbreviation: Syn-D 2-3 = syn-D 2 rutile grains transposed in D 3 fabrics.

  -Pb geochronology of monazite grains from the kyanite-micaschists (samples CHI0999#93-17-a and -b) was conducted by in-situ (directly on thin sections) laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) at Géosciences Rennes (France) using a ESI NWR193UC Excimer laser coupled to a quadripole Agilent 7700x ICP-MS. A C C E P T E D M A N U S C R I P T

  FIGURE 8

  second generation of sulfides is associated with the development of the D 2 metamorphic fabrics (steep-dipping S 2 schistosity) as a chalcopyrite-pyrrhotite assemblage (sample CHI0999#89-16-b) and a chalcopyrite-bornite assemblage (sample CHI0999#93-17a) in the matrix of the micaschists, parallel with S 2 delineated by phlogopite and muscovite (001) cleavage planes.

  Fig. 13b), data from sample CHI0999#93-17-a and -b are concordant to sub-concordant and spread along the Concordia curve. These monazite grains are related to D 2 deformation-metamorphic stage and transposed and partially recrystallized during D 3 deformation-metamorphic stage. Their recrystallization A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT is thus synchronous with the syn-D 3 Cu mineralization and/or with the development of the S 3

(

  chalcopyrite-pyrrhotite) and a second generation of kyanite porphyroblasts (Ky 2 ) locally kinked and wrapped by the later S 3 schistosity. These textural observations lead us to propose that these porphyroblasts have developed during D 2 metamorphic stage and have recrystallized during D 3 metamorphic stage and are thus denominated as Ky 2-3 porphyroblasts. Similarly, some monazite grains aligned with relics of the S 2 schistosity (see section 5.4.2.) are interpreted as developed during the D 2 metamorphic stage. In garnet-micaschists, the A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT onset of the crystallization of garnet poikiloblasts is attributed to this metamorphic stage. The P-T conditions recorded by the S 2 mineral paragenesis indicate an isothermal decompression from ca. 620 to 580°C. These structural and metamorphic data are interpreted to record synorogenic exhumation. The final deformation stage, D 3 , is marked by the transposition of the steep-dipping S 2 schistosity in a shallow-dipping S 3 schistosity, by the kinking and recrystallization of the second generation of sub-automorphous kyanite (designated as Ky 2-3 ), a third generation of Cu sulfides (chalcopyrite and bornite), monazite and rutile grains oriented parallel to the (001) cleavage plane of associated micas defining the shallow-dipping S 3 schistosity. Most of the crystallization of syn-D 2-3 garnet poikiloblasts is attributed to this metamorphic paragenesis. Zr-in-rutile geothermometry data obtained on rutile grains oriented parallel to the (001) cleavage plane of syn-S 3 micas lead to the computation of temperatures between 580 and 620±50°C (Syn-D 2-3 , Figs. 14b and 15, Table 5). This range of temperatures corresponds to those estimated by Eglinger et al. (accepted) for the development of the steep-dipping schistosity (S 2 ) in the internal zone of the Lufilian belt (P = 6-8 kbar; T = 600-640°C). As the rutile grains analyzed for Zr-in-rutile geothermometry delineate the shallow-dipping S 3 schistosity but display temperatures consistent with the development of the steep-dipping S 2 schistosity, we propose that these rutile grains record the development of the D 2 paragenesis between 580 and 620±50°C (Syn-D 2-3 , Figs. 14b and 15, Table 5) and have been transposed in the S 3 schistosity. These MP-MT conditions and the steep-dipping fabrics have been attributed to the D 2 syn-orogenic exhumation of high-grade metamorphic rocks, due to tectonic accretion of subducted continental units decoupled from the down-going slab. Even though the garnet-phlogopite equilibrium is coeval with the development of the S 3 schistosity, it records temperatures from 630 to 635±25°C (

  obtained by Zr-in-rutile geothermometry in the present study and which record the emplacement of the D 2 metamorphic paragenesis between 580 and 620±50°C. This difference might result from (i) a thermodynamic disequilibrium between garnet, which might have preserved its syn-D 2 chemical composition, and syn-D 3 phlogopite; or (ii) an augmentation of temperature between D 2 and D 3 metamorphic stages due to a heat production during thermal relaxation in the thickened orogenic crust induced by the radioactive decay of radioisotopes (cf.[START_REF] Vanderhaeghe | The thermal-mechanical evolution of crustal orogenic belts at convergent plate boundaries: A reappraisal of the orogenic cycle[END_REF]. However, an augmentation of temperature between D 2 and D 3 metamorphic stages is not reported in the estimations ofEglinger et al. (accepted) or in the present study where there is no evidence of such an augmentation between D 2 and D 3 metamorphic paragenesis or in the temperatures recorded by rutile grains.Monazite grains in Lumwana's Cu-rich kyanite-micaschists associated with relics of the S 2 schistosity and locally transposed and partially recrystallized during the D 3 metamorphic event yield 208 Pb/ 232 Th ages ranging from 537.1±6.6 down to 502.8±6.3 Ma (Fig.13b, see section 5.4.2. for details, Fig.10). The scattering of these ages (Fig.13c) is interpreted as recording decompression coeval with ductile deformation, i.e. monazite grains crystallized during a continuum of deformation from the initiation of the D 2 metamorphic stage around ca. 540 Ma down to the end of the D 3 deformation stage in the kyanite stability field (Ky 2-3 ) at ca. 500 Ma. Data from literature constrain the peak of metamorphism (designated in the present study as D 1 event) at ca. 550-530 Ma(Eglinger et al., 2014b, accepted; John et al., 2004). The 208 Pb/ 232 Th ages obtained in the present study on syn-to latemetamorphic monazite grains fall within the margins of the D 1 stage constraints and probably record the retrograde clockwise P-T path from the D 2 to the D 3 metamorphic stages. This D 3 deformation stage is ended by C 3 shear bands marked by retrogression of phlogopite into chlorite (Fig.8f). These shear bands (i) crosscut all previous metamorphic fabrics, (ii) are associated with the formation of euhedral pyrite and tourmaline crystals and A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT (iii) locally remobilize Cu sulfides. This late-D 3 event is interpreted as the expression of postorogenic gravitational collapse coeval with cooling of the high-grade metamorphic nappes of the Lufilian orogenic belt (D 3 deformation-metamorphic stage, Fig. 15). This is further corroborated by the temperature from 610 down to 540±50°C yielded by rutile grains associated with remobilized sulfides and shear bands associated with the late-D 3 metamorphic fabrics development (Late-D 3 , Fig. 14b, Table

  and Bernau et al. (2013) who A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT proposed the presence of Cu in the protolith of the micaschists prior to the peak of metamorphism. The second generation of sulfides, marked by a chalcopyrite-pyrrhotite (sample CHI0999#89-16-b) or chalcopyrite-bornite assemblage (sample CHI0999#93-17-a), is coeval with the development of a second steep-dipping S 2 schistosity, initiating the retrograde P-T path (D 2 metamorphic event), and a second generation of kyanite porphyroblasts later transposed in the S 3 schistosity (Ky 2-3 porphyroblasts).

  monazite grains, which are co-genetic (i) with the syn-D 3 mineralization and (ii) with the development of the S 2 and S 3 schistosities, and which display 208 Pb/ 232 Th ages from 537.1±6.6 Ma to 502.8±6.3 Ma (Figs. 10). These new data evidence that a Cu mineralizing event developed during the whole D 3 phase in the kyanite stability field from ca. 540 Ma to ca. 500 Ma, i.e. during the syn-to post-orogenic exhumation of the high-grade metamorphic rocks forming the orogenic root of the Pan-African Lufilian belt (D 3 deformation-metamorphic stage, Fig.15). This Cu mineralizing event overlaps with the U-Pb ages obtained on synmetamorphic uraninite dated at 531±5 Ma(Eglinger et al., accepted) from kyanite-micaschists sampled in the same drill core, and overlap, within their uncertainty, the Re-Os ages ranging from 534.4±2.2 to 524.8±2.2 Ma obtained by[START_REF] Nowecki | Tracing seawater evaporation and its role in the formation of sedimenthosted stratiform copper deposits[END_REF] on syn-metamorphic molybdenite from the Lumwana deposit. This author proposes that the molybdenite is synmetamorphic and that the ages obtained on this phase are coeval with the metamorphic peak Cu mineralization.In addition to these textural observations and geochronological data,Eglinger et al. (2014a) described the circulation of CaCl 2 -NaCl-KCl-(MgCl 2 ) fluids in two uranium occurrences from the Western Zambian Copperbelt (Lolwa and Mitukuluku, Fig.1), during a high-temperature (500-700°C) syn-deformation stage of the Pan-African metamorphism of the Lufilian belt(Eglinger et al., 2014a, b). The analysis of these fluid inclusions by LA-ICP-MS reveals (i) high U contents (from 1 to 570 μg.g -1 of U in the Lolwa occurrence and from 5 to 150 μg.g -1 in the Mitukuluku occurrence,Eglinger et al., 2014a) but also (ii) high Cu concentrations (from 1300 to 22000 μg.g -1 of Cu in Lolwa and from 480 to 2300 μg.g -1 in A C C E P T E D M A N U S C R I P T

  Lolwa and Mitukuluku indicates that they are associated with this U-and Cu-rich fluid circulation at ca. 530 Ma at minimum P-T conditions of ca. 5 kbar and 500°C(Eglinger et al., 2014a, b). As the Lumwana deposit displays similarities with the ones of Lolwa and Mitukuluku (mineralization hosted in kyanite-micaschists, upper amphibolite metamorphic facies recorded at ca. 550 Ma), and is located between these two localities, we propose that the highly-saline fluid described byEglinger et al. (2014a) in the uranium occurrences of Lolwa and Mitukuluku have also circulated in the Mwombezhi Dome, in particular at Lumwana. All these features suggest that some syn-D 2 Cu and U elements are mobilized in the system by metamorphic fluids linked to the dissolution of evaporitic rocks. The metals transferred in these highly-saline fluids might originate from (i) an in-situ remobilization of an older sulfide stock already present in the host rocks, and/or (ii) another host rock. Whether the syn-orogenic remobilization of copper sulfides is related or not to a new input of metals during the Lufilian orogeny remains an open question. As textural evidence led us to conclude that some Cu was present in the protolith of the kyanite-micaschists before metamorphism, we propose that at least part of the syn-metamorphic Cu deposition occurred by remobilization of the host rocks and their preexisting sulfides assisted by the circulation of highly-saline metamorphic fluids during the Pan-African orogeny. Such an in-situ remobilization of Cu-sulfides during metamorphism with no addition of Cu is also proposed by[START_REF] Benham | Copper occurrences of the Mombezhi Dome Area, Northwestern Zambia[END_REF],[START_REF] Bernau | The Geology and geochemistry of the Lumwana basement hosted Copper-Cobalt (Uranium) deposits[END_REF] and[START_REF] Bernau | The geology and geochemistry of the Lumwana Cu (± Co ± U) deposits, NW Zambia[END_REF].A final remobilization of sulfides occurred during the final stage of the retrograde P-T path during localized deformation in shallow-dipping shear zones (late-D 3 event). This late-D 3A C C E P T E DM A N U S C R I P TACCEPTED MANUSCRIPTphase postdates syn-D 3 monazite grains which yield youngest 208 Pb/ 232 Th ages of ca. 500 Ma.

(

  see section 5.4.3.) in kyanite-micaschists and in garnet-micaschists. The position of rutile from the Lumwana micaschists in the Cr vs Nb diagram (Fig. 14a), proposed by Zack et al. (2004b), Meinhold et al. (2008) and Triebold et al. (2007) point to a metapelitic environment of crystallization for all analyzed rutile grains. However, rutile from garnet-micaschists display a different Cr/Nb ratio compared to those from the kyanite-micaschists suggesting the A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT chemical environment of rutile crystallization differed in these two distinct chemical layers

  invoke a high metamorphic grade and pervasive A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT deformation for the host rock of the mineralization with slivers of gneisses interleaved with micaschists, and a transitional contact between the gneiss and the ore schist. These observations led them to propose that the mineralization at the Lumwana deposit might be hosted in the basement of the Lower Roan. However, they do not precise if the protolith of the Cu-bearing micaschists is sedimentary or magmatic in origin. Even though we can conclude a sedimentary origin for Lumwana's kyanite-micaschists, no evidence allows us to conclude that these metasediments are part of the Katanga metasedimentary sequence or of its basement. The identification of several generations of Cu sulfides leads to the following hypotheses: (i) an in-situ syn-tectonic remobilization with no addition of metals or (ii) a new input of metals during the Pan-African orogeny. Two lines of evidences argue in favor of insitu remobilization: (i) Cu-bearing minerals are present in the non-metamorphic external zone (i.e. Congolese Copperbelt) and are also present as inclusions in porphyroclasts indicating that at least some Cu was present in the protolith of the kyanite-micaschists (i.e. oreschists) before metamorphism; and (ii) isotopic data (Lu/Hf) obtained by Eglinger (2013) indicates that the rocks of the Zambian Copperbelt are mostly originating from reworked Neo-Archean and Paleoproterozoic rocks with a minor Neoproterozoic input. However, if these sediments are part of the basement of the Katanga metasedimentary sequence, the metamorphic metals-rich brines circulation identified by Eglinger et al. (2014a), which originates from the dissolution of the Roan evaporites, might represent a new input of metals during the Lufilian orogeny.

  the crystallization of sulfides related to hydrothermal fluids during diagenesis leading to the formation of sediment-hosted stratiform deposits and (ii) a remobilization, with some dispersion, of this initial Cu metal stock associated with intracrystalline deformation, during the Pan-African deformation, metamorphism and metasomatism, assisted by the circulation of highly-saline fluids. A long and continuous remobilization of sulfides has occurred during the retrograde clockwise P-T path, first during syn-orogenic exhumation (ca. 540-510 Ma), then during post-orogenic exhumation (ca. 510-500 Ma) accommodated by pervasive ductile deformation in the kyanite stability field, and finally during late post-orogenic exhumation associated with localized shallow-dipping shear zones (younger than ca. 500 Ma). These successive tectonic phases recorded by the Lufilian belt, namely burial, syn-orogenic exhumation and post-orogenic exhumation, are typical of Phanerozoic orogenic belts (e.g. Vanderhaeghe, 2012 and references therein).

Fig. 1 :

 1 Figure captions

Fig. 2 :

 2 Fig. 2: Lithostratigraphy of the Katanga Supergroup in the Congolese Copperbelt (External

Fig. 3 :

 3 Fig. 3: Geological map of the Mwombezhi Dome, showing the location of the Malundwe

Fig. 4 :

 4 Fig. 4: Cross section across the Chimiwungo prospect (looking north) showing the position of

Fig. 5 :Fig. 6 :

 56 Fig. 5: Garnet or kyanite Cu-rich micaschists drill core samples CHI0999#88-13, 89-16 and

Fig. 7 :

 7 Fig. 7: Photograph of sample CHI0999#93-17-b under microscope (polarized and analyzed

Fig. 8 :

 8 Fig. 8: Photomicrographs illustrating kyanite-micaschists petrography and microstructures

Fig. 9 :Fig. 10 :Fig. 11 :

 91011 Fig. 9: Photomicrographs illustrating the mineralization of kyanite-micaschists from samples

Fig. 12 :

 12 Fig. 12: Paragenetic sequence of garnet and kyanite-micaschists from the Lumwana deposit

Fig. 13 :Fig. 14 :

 1314 Fig. 13: Geochemical signatures and 208 Pb/ 232 Th ages of syn-S 3 monazite grains from

Fig. 15 :

 15 Fig. 15: Synthetic P-T-m diagram showing possible P-T path for Lumwana's Cu(-U)-rich

4.3.2. Zr-in-rutile geothermometry

	. Repeated analyzes of Manangoutry monazite standard (555.2
	± 4.3 Ma (MSWD=1.6; n=6); TIMS age 555 ± 2 Ma; Paquette and Tiepolo, 2007) treated as
	unknown were used to control the reproducibility and accuracy of the corrections. Data
	reduction was carried out with the GLITTER® software package developed by the Macquarie
	Research Ltd.. Concordia diagrams were generated using Isoplot/Ex (Ludwig, 2001). All
	errors given in Table 1 are listed at two sigma, but where data are combined to calculate
	weighted means, the final results are provided with 95% confidence limits.
	Cr ( 53 Cr), Zr ( 90 Zr and 91 Zr), and Nb ( 93 Nb) concentrations in rutile were quantified at
	GeoRessources (Nancy, France) using a laser ablation-inductively coupled plasma mass
	spectrometry (LA-ICP-MS) system composed of a GeoLas excimer laser (ArF, 193 nm,
	Microlas) coupled to a conventional transmitted and reflected light microscope (Olympus
	BX51) for sample observation and laser beam focusing onto the sample and an Agilent 7500c

  Similarly, the Ce 2 O 3 content is correlated with La 2 O 3 (10.18 wt.% to 13.2 wt.%). These variations of REE 3+ are negatively correlated with the CaO

Table 3 and indicate that the P 2 O 5 content of the analyzed grains is quite homogeneous (29.19 to 31.07 wt.%). Even though the studied grains are mostly composed of monazite-(Ce) (Ce 2 O 3 content from 26.27 to 32.83 wt.%) they display some chemical variations with a correlation between the CaO (0.43 wt.% to 1.65 wt.%) and ThO (2.04 wt.% to 10.6 wt.%) contents.

  , increasing the abundance of Th and thus relatively decreasing the U one. Accordingly, the 235 U/ 207 Pb chronometer is associated with a large uncertainty, it is therefore more pertinent to look at the data in a 206 Pb/ 238 U versus 208 Pb/ 232 Th

	Concordia diagram. Twelve monazite grains from sample CHI0999#93-17-a and six from
	sample CHI0999#93-17-b have been analyzed (Table 1).
	Plotted in 206 Pb/ 238 U vs 208 Pb/ 232 Th concordia diagrams (

Table 6

 6

) at 6 kbar (minimum pressure recorded for this stage by Eglinger et al., accepted; see section 6.2. for details), which are

Table 1 :

 1 208 Pb/ 232 Th monazite dating using LA-ICP-MS from samples CHI0999#93-17-a & -17-b.

	Sample	Analysis		Concentrations / ppm			Isotopic ratios		Ages / Ma
		n°	Pb	Th	U	Th/U	206 Pb/ 238 U	2σ	208 Pb/ 232 Th	2σ	208 Pb/ 232 Th	2σ
	CHI0999#93-17-a	1-1	893	26664	4016	6.6	0.08311 0.00107 0.02563 0.00031	511.4	6.2
		1-2	1026	30911	4494	6.9	0.08350 0.00107 0.02564 0.00031	511.6	6.2
		1-3	1305	41223	5131	8.0	0.08348 0.00108 0.02552 0.00031	509.3	6.2
		1-4	924	28083	3769	7.5	0.08436 0.00109 0.02613 0.00032	521.3	6.3
		1-5	736	20945	3513	6.0	0.08461 0.00109 0.02622 0.00032	523.2	6.4
		1-6	872	23901	3594	6.6	0.08491 0.00110 0.02652 0.00033	529.0	6.5
		1-7	896	23679	3963	6.0	0.08491 0.00110 0.02672 0.00033	533.0	6.5
		2-1	1063	26505	5309	5.0	0.08476 0.00110 0.02678 0.00033	534.2	6.5
		2-2	1073	29815	4123	7.2	0.08563 0.00111 0.02693 0.00033	537.1	6.6
		2-3	897	20691	5243	3.9	0.08521 0.00111 0.02635 0.00033	525.7	6.5
		2-4	859	23603	3942	6.0	0.08357 0.00109 0.02595 0.00033	517.8	6.4
		2-5	843	23118	3955	5.8	0.08303 0.00109 0.02586 0.00033	516.1	6.4
		3-1	968	27701	4116	6.7	0.08211 0.00108 0.02601 0.00033	519.0	6.5
		3-2	856	24584	3905	6.3	0.08123 0.00107 0.02535 0.00032	506.0	6.3
		4-1	1043	30807	4108	7.5	0.08237 0.00108 0.02605 0.00033	519.7	6.5
		5-1	666	16385	4142	4.0	0.08163 0.00108 0.02569 0.00033	512.8	6.4
		5-2	606	13933	3907	3.6	0.08507 0.00112 0.02612 0.00033	521.1	6.5
		5-3	827	23018	4297	5.4	0.08139 0.00108 0.02540 0.00032	507.0	6.4
		6-1	615	15173	3924	3.9	0.08154 0.00108 0.02538 0.00032	506.6	6.4
		7-1	845	24186	4264	5.7	0.08134 0.00108 0.02519 0.00032	502.8	6.3
		8-1	781	21161	4159	5.1	0.08164 0.00109 0.02612 0.00034	521.1	6.6
		8-2	899	24353	4688	5.2	0.08230 0.00110 0.02634 0.00034	525.5	6.7
		8-3	866	23898	4492	5.3	0.08210 0.00110 0.02602 0.00034	519.2	6.6
		9-1	595	15214	3478	4.4	0.08290 0.00111 0.02622 0.00034	523.2	6. 7
		10-1	642	15788	3984	4.0	0.08201 0.00110 0.02569 0.00033	512.8	6.6
		11-1	876	20078	5799	3.5	0.08337 0.00112 0.02614 0.00034	521.5	6.7
		11-2	860	21623	5039	4.3	0.08217 0.00111 0.02620 0.00034	522.8	6.7
		12-1	681	17055	3974	4.3	0.08196 0.00111 0.02646 0.00034	527.8	6. 8
	CHI0999#93-17-b	1-1	2642	87071	6599	13.2	0.08360 0.00112 0.02637	0.00035	526.2	6.9
		2-1 3-1 4-1 4-2 5-1 5-2 6-1 6-2 6-3	1941 1729 1751 1064 1300 1295 2151 1754 1079	60195 56671 52087 32648 40675 41400 71100 58895 34137	6910 5206 6716 3934 4219 4366 5733 4464 3757	8.7 10.9 7.8 8.3 9.6 9.5 12.4 13.2 9.1	0.08236 0.00110 0.02572 5 0.08190 0.00109 0.02545 1154 0.08324 0.00111 0.02597 1923 0.08361 0.00112 0.02612 1154 0.08485 0.00113 0.02645 5 0.08398 0.00112 0.02564 1923 0.08205 0.00110 0.02635 4231 0.08308 0.00111 0.02607 5769 6923 0.08268 0.00110 0.02561	0.00034 0.00034 0.00034 0.00035 0.00035 0.00034 0.00035 0.00034 0.00034	513.3 508.0 518.2 521.3 527.7 511.8 525.8 520.3 511.2	6.7 6.6 6.8 6.8 6.9 6.6 6.8 6.7 6.6
									5385

Table 2 :

 2 Average mineral compositions with confidence interval of 95% in brackets (n = number of samples) from samples CHI0999#88-13, 88-16-b and 93-17-b. Abbreviations: Chl = chlorite; Ms = muscovite; Phl = phlogopite.

	Mineral		Phl		Chl		Ms
	Structural position	Pre-D3	Syn-D3	Pre-D3	Late-D3	Syn-D2	Syn-D3
	Sample		93-17-b	89-16-b	88-13	89-16-b	89-16-b	89-16-b
	Oxides	SiO2	39.65	36.73	24.25	27.67	46.65	46.44
	wt.%		(0.34)	(0.35)	(0.37)	(2.25)	(0.40)	(0.41)
		TiO2	1.04	1.40	0.04	0.21	0.74	0.70
			(0.06)	(0.07)	(0.02)	(0.28)	(0.04)	(0.08)
		Al2O3	18.24	18.70	22.17	18.24	33.80	33.96
			(0.19)	(0.16)	(0.24)	(0.48)	(0.52)	(0.53)
		FeO	6.16	13.95	26.66	27.80	0.66	0.69
			(0.23)	(0.85)	(1.33)	(3 .79)	(0.09)	(0.06)
		MnO	0.03	0.05	0.07	0.05	0.01	0.03
			(0.01)	(0.02)	(0.03)	(0.04)	(0.01)	(0.01)
		MgO	19.76	13.65	12.81	12.09	1.45	1.33
			(0.25)	(0.84)	(1.13)	(1.20)	(0.15)	(0.21)
		CaO	0.03	0.07	0.05	0.11	0.02	0.05
			(0.02)	(0.08)	(0.02)	(0.06)	(0.01)	(0.02)
		Na2O	0.42	0.26	0.03	0.06	0.89	0.85
			(0.03)	(0.09)	(0.02)	(0.06)	(0.06)	(0.04)
		K2O	9.12	9.61	0.06	1.06	9.86	9.88
			(0.13)	(0.19)	(0.07)	(1.87)	(0.17)	(0.14)
		Total	98.69	98.49	88.18	87.33	98.59	98.38
			(0.22)	(0.30)	(0.32)	(1.74)	(0.66)	(0.58)
	Oxygens		22	22	14	14	11	11
	Cations	Si	5.662	5.489	2.499	1.057	6.255	6.254
			(0.035)	(0.027)	(0.280)	(0.343)	(0.031)	(0.040)
		Al IV	2.338	2.511	1.644	0.515	1.745	1.746
			(0.035)	(0.027)	(0.207)	(0.197)	(0.031)	(0.040)
		Al VI	0.733	0.785	1.056	0.327	3.595	3.645
			(0.028)	(0.023)	(0.123)	(0.108)	(0.034)	(0.066)
		Ti	0.111	0.157	0.003	0.004	0.075	0.071
			(0.006)	(0.009)	(0.001)	(0.004)	(0.004)	(0.008)
		Fe tot	0.736	1.747	2.327	0.937	0.075	0.070
			(0.028)	(0.115)	(0.383)	(0.363)	(0.010)	(0.018)
		Mn	0.003	0.006	0.007	0.001	0.001	0.003
			(0.002)	(0.003)	(0.004)	(0.001)	(0.001)	(0.002)
		Mg	4.207	3.035	1.936	0.687	0.289	0.254
			(0.052)	(0.169)	(0.137)	(0.221)	(0.030)	(0.052)
		Ca	0.005	0.012	0.006	0.005	0.003	0.003
			(0.002)	(0.013)	(0.004)	(0.004)	(0.057)	(0.002)
		Na	0.117	0.077	0.005	0.004	0.230	0.227
			(0.009)	(0.027)	(0.005)	(0.002)	(0.016)	(0.017)
		K	1.661	1.833	0.008	0.029	1.687	1.483
			(0.024)	(0.039)	(0.010)	(0.046)	(0.038)	(0.388)

Table 3 :

 3 Representative monazite analyses from samples CHI0999#93-17-a & -17-b obtained using EMP.

	Sample		93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a
	Analysis n°		1-1	1-2	1-3	1-4	1-5	1-6	1-7	1-9	1-10	1-11	1-12	1-13	1-14	2-1	2-2	2-3	2-4	2-5
	Oxides/ wt.%	P2O5	30.10	30.33	30.12	30.44	29.85	30.28	30.38	30.06	30.10	30.33	30.12	30.44	29.85	30.28	30.38	30.06	30.10	30.33
		SiO2	0.21	0.18	0.25	0.22	0.36	0.19	0.25	0.28	0.21	0.18	0.25	0.22	0.36	0.19	0.25	0.28	0.21	0.18
		CaO	1.34	0.32	0.51	1.14	0.70	0.26	0.56	0.71	1.34	0.32	0.51	1.14	0.70	0.26	0.56	0.71	1.34	0.32
		Y2O3	1.03	0.50	1.55	0.95	1.39	0.57	1.62	1.44	1.03	0.50	1.55	0.95	1.39	0.57	1.62	1.44	1.03	0.50
		La2O3	17.27	16.19	17.00	17.65	16.79	16.15	16.75	15.80	17.27	16.19	17.00	17.65	16.79	16.15	16.75	15.80	17.27	16.19
		Ce2O3	25.97	31.20	28.75	27.05	28.17	30.81	28.45	27.73	25.97	31.20	28.75	27.05	28.17	30.81	28.45	27.73	25.97	31.20
		Pr2O3	3.25	4.31	3.68	3.38	3.73	4.05	3.58	3.82	3.25	4.31	3.68	3.38	3.73	4.05	3.58	3.82	3.25	4.31
		Nd2O3	11.09	14.37	12.57	11.23	12.59	14.27	12.72	13.47	11.09	14.37	12.57	11.23	12.59	14.27	12.72	13.47	11.09	14.37
		Sm2O3	1.66	1.86	1.69	1.63	1.73	2.03	1.73	2.05	1.66	1.86	1.69	1.63	1.73	2.03	1.73	2.05	1.66	1.86
		Gd2O3	1.75	0.95	1.42	1.56	1.48	1.13	1.46	1.55	1.75	0.95	1.42	1.56	1.48	1.13	1.46	1.55	1.75	0.95
		PbO	0.15	0.04	0.07	0.13	0.08	0.02	0.06	0.09	0.15	0.04	0.07	0.13	0.08	0.02	0.06	0.09	0.15	0.04
		ThO2	5.88	0.36	1.76	4.95	2.46	0.47	1.98	2.91	5.88	0.36	1.76	4.95	2.46	0.47	1.98	2.91	5.88	0.36
		UO2	0.00	0.03	0.02	0.00	0.03	0.05	0.02	0.00	0.00	0.03	0.02	0.00	0.03	0.05	0.02	0.00	0.00	0.03
		Total	99.70	100.64	99.39	100.33	99.36	100.28	99.56	99.91	99.70	100.64	99.39	100.33	99.36	100.28	99.56	99.91	99.70	100.64
	Oxygens		4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4
	Cations	P	0.996	0.997	0.996	0.999	0.990	0.998	1.000	0.993	0.996	0.997	0.996	0.999	0.990	0.998	1.000	0.993	0.996	0.997
		Si	0.008	0.007	0.010	0.009	0.014	0.007	0.010	0.011	0.008	0.007	0.010	0.009	0.014	0.007	0.010	0.011	0.008	0.007
		ƩT-site	1.004	1.004	1.006	1.007	1.004	1.005	1.010	1.004	1.004	1.004	1.006	1.007	1.004	1.005	1.010	1.004	1.004	1.004
		Ca	0.056	0.013	0.021	0.047	0.029	0.011	0.023	0.030	0.056	0.013	0.021	0.047	0.029	0.011	0.023	0.030	0.056	0.013
		Y	0.021	0.010	0.032	0.020	0.029	0.012	0.034	0.030	0.021	0.010	0.032	0.020	0.029	0.012	0.034	0.030	0.021	0.010
		La	0.249	0.232	0.245	0.252	0.243	0.232	0.240	0.227	0.249	0.232	0.245	0.252	0.243	0.232	0.240	0.227	0.249	0.232
		Ce	0.372	0.443	0.411	0.384	0.404	0.439	0.405	0.396	0.372	0.443	0.411	0.384	0.404	0.439	0.405	0.396	0.372	0.443
		Pr	0.046	0.061	0.052	0.048	0.053	0.057	0.051	0.054	0.046	0.061	0.052	0.048	0.053	0.057	0.051	0.054	0.046	0.061
		Nd	0.155	0.199	0.175	0.155	0.176	0.198	0.177	0.188	0.155	0.199	0.175	0.155	0.176	0.198	0.177	0.188	0.155	0.199
		Sm	0.022	0.025	0.023	0.022	0.023	0.027	0.023	0.028	0.022	0.025	0.023	0.022	0.023	0.027	0.023	0.028	0.022	0.025
		Gd	0.023	0.012	0.018	0.020	0.019	0.015	0.019	0.020	0.023	0.012	0.018	0.020	0.019	0.015	0.019	0.020	0.023	0.012
		Pb	0.002	0.000	0.001	0.001	0.001	0.000	0.001	0.001	0.002	0.000	0.001	0.001	0.001	0.000	0.001	0.001	0.002	0.000
		Th	0.052	0.003	0.016	0.044	0.022	0.004	0.018	0.026	0.052	0.003	0.016	0.044	0.022	0.004

Table 4 :

 4 Representative rutile analyses from samples CHI0999#88-13, 93-17-a & -17-b obtained using LA-ICP-MS.47 Ti was used as internal standard, using [TiO 2 ]= 100wt.%. Abbreviation: Syn-D 2-3 = syn-D 2 rutile grains transposed in D 3 fabrics.

	Sample		88-13	88-13	88-13	88-13	88-13	88-13	93-17-a	93-17-b	93-17-b	93-17-b	93-17-b	93-17-b	93-17-b	93-17-b
	Analysis n°		8	9	10	11	12	13	14	15	16	17	19	20	21	22
	Structural position		Pre-D3	Pre-D3	Pre-D3	Pre-D3	Pre-D3	Pre-D3	Syn-D2-3	Syn-D2-3	Syn-D2-3	Syn-D2-3	Syn-D2-3	Syn-D2-3	Syn-D2-3	Syn-D2-3
	Elements (ppm)	53 Cr	65	84	74	78	80	80	472	512	470	329	429	430	506	526
		90 Zr	59	70	74	66	70	70	116	106	100	98	112	140	133	135
		91 Zr	59	72	73	65	67	71	114	109	100	99	110	142	131	136
		93 Nb	2400	5650	5440	4670	3720	4510	6230	5330	4760	3470	5850	7300	6410	6150
	Sample		93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a	93-17-a
	Analysis n°		23	24	25	26	27	28	29	2	3	4	5	6	7
	Structural position		Syn-D2-3	Syn-D2-3	Syn-D2-3	Syn-D2-3	Syn-D2-3	Syn-D2-3	Syn-D2-3	Late-D3	Late-D3	Late-D3	Late-D3	Late-D3	Late-D3
	Elements (ppm)	53 Cr	369	377	389	397	398	429	458	394	359	393	401	351	383
		90 Zr	106	114	112	113	101	121	134	121	125	120	125	76	117
		91 Zr	103	113	114	113	101	122	135	121	124	121	125	77	117
		93 Nb	3950	3850	5170	4810	4600	5350	5980	5109	4430	5625	5684	3390	4640

Table 5 :

 5 Zr-in-rutile thermometry for representative rutile grains from different structural positions from samples CHI0999#88-13, 93-17-a & -17-b. Zr content was obtained using LA-ICP-MS. Abbreviation: Syn-D 2-3 = syn-D 2 rutile grains transposed in D 3 fabrics.

	Structural position	Sample	Analysis n°	Zr content (ppm) 2σ	Zack et al. (2004a) thermometer Temperature (°C) Uncertainty
	Syn-D 2-3	CHI0999#93-17-a	14	116	8	597	50
	Syn-D 2-3	CHI0999#93-17-b	15	106	3	586	50
	Syn-D 2-3	CHI0999#93-17-b	16	100	2	578	50
	Syn-D 2-3	CHI0999#93-17-b	17	98	2	576	50
	Syn-D 2-3	CHI0999#93-17-b	19	112	4	593	50
	Syn-D 2-3	CHI0999#93-17-b	20	140	2	621	50
	Syn-D 2-3	CHI0999#93-17-b	21	133	2	615	50
	Syn-D 2-3	CHI0999#93-17-b	22	135	3	617	50
	Syn-D 2-3	CHI0999#93-17-a	23	106	3	586	50
	Syn-D 2-3	CHI0999#93-17-a	24	114	3	595	50
	Syn-D 2-3	CHI0999#93-17-a	25	112	4	593	50
	Syn-D 2-3	CHI0999#93-17-a	26	113	4	594	50
	Syn-D 2-3	CHI0999#93-17-a	27	101	4	580	50
	Syn-D 2-3	CHI0999#93-17-a	28	121	4	603	50
	Syn-D 2-3	CHI0999#93-17-a	29	134	7	616	50
	Late-D 3	CHI0999#93-17-a	2	121	2	603	50
	Late-D 3	CHI0999#93-17-a	3	125	2	607	50
	Late-D 3	CHI0999#93-17-a	4	120	2	602	50
	Late-D 3	CHI0999#93-17-a	5	125	2	608	50
	Late-D 3	CHI0999#93-17-a	6	76	1	544	50
	Late-D 3	CHI0999#93-17-a	7	117	3	598	50

Acknowledgements

The authors would like to thank Barrick Ltd. for providing access to Chimiwungo drill cores. CNRS (NEEDS) and AREVA are also thanked for financial support. The authors are grateful to Sandrine Mathieu (SEM), Lise Salsi (SEM) and Olivier Rouer (EMP) (GeoRessources, Nancy) for technical support in providing analytical data on SEM and EMP. The authors also thank Bruce Eglington and Philippe Muchez for careful review and Franco Pirajno for editorial handling that helped to improve the paper.

A C C E P T E D

M A N U S C R I P T

Conflict of interest:

 None

A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

Graphical abstract

A C C E P T E D M A N U S C R I P T

ACCEPTED MANUSCRIPT

Research highlights:

 A new paragenetic sequence for the Cu(-U)-rich kyanite-micaschists of the Lumwana Cu deposit (Western Zambian Copperbelt)  P-T-t record of these metamorphosed lithologies  Prograde D 1 event coeval with a primary Cu mineralizing event  Retrograde D 2 event (syn-orogenic exhumation of these HP units) reworking the primary generation of sulfides at ca. 540-510 Ma and 580-620°C  Retrograde D 3 event (post-orogenic exhumation of these HP units) reworking the copper sulfides at ca. 510-500 Ma  Retrograde late-D 3 event (late post-orogenic exhumation of these HP units) younger than ca. 500 Ma and between 540-610°C reworking the copper sulfides