Moussa Dabo

Tahar Aïfa
email: tahar.aifa@univ-rennes1.fr

Ibrahima Gassama

Malick Papa

Ngom

Papa Malick Ngom

Revised version Thrust totranspression and transtension tectonics during the Paleoproterozoic evolution of the Birimian Greenstone Belt of Mako, Kédougou-Kéniéba Inlier, Eastern Senegal

Keywords: Eburnean, Birimian, thrust, transpression, transtension, Kédougou-Kéniéba inlier

The structural cartography of the Birimian formations of the Mako area shows a polyphase deformation marked by variable structures such as imbricated shear zones, thrusts and reverse-shears, poly-folding, boudinage, normal faults. The multiscale analysis of the various mapped structures combined with the satellite images allowed us to distinguish three major phases of Eoeburnean and Eburnean deformation.

The Eoeburnean D 1 deformation phase is preserved through ductile structures in some lithologies (metabasalts, quartzites). It is composed of early thrusting and late sinistral reverse-shearing due to a NW-SE principal shortening direction, which involved large overturned folds verging northwestward and associated with thrust faults. It is also associated with the emplacement of early granitoids (c. 2200 Ma) followed by andesitic to felsic volcanic rocks around c. 2160 Ma. The Eburnean event is divided into two phases of deformation namely D 2 and D 3 . The D 2 phase is the early Eburnean event which involves a sinistral transpressive deformation. It is characterized by a NNE-SSW shortening direction which creates major NNW-SSE (N160°-170°) and NNE-SSW (N20°-30) sinistral reverse-shear zones associated with ENE-WSW (N60°-70°) dextral reverse-shear zones. Interference between both major NNE-SSW and NNW-SSE reverse-shear zones involves an anatomizing pattern of deformation. The D 3 phase is a transtensional deformation associated with a dextral movement which creates dextral shear zones and conjugate normal faults leading to graben depression. The D 3 principal maximum stress is ENE-WSW oriented. The granitoids were emplaced during these Eoeburnean and Eburnean orogenic events.

Introduction

The Man-Leo shield represents the southern part of the West African Craton (WAC). It is composed of two generations of Precambrian rocks, the Paleoproterozoic "Birimian" rocks in the east, and the Archean cratonic nucleus in the west which are tectonically separated by the Sassandra fault [START_REF] Bessoles | Géologie de l'Afrique. Le craton Ouest-Africain[END_REF][START_REF] Feybesse | La limite Archéen-Protérozoïque inférieur de l'Afrique de l'Ouest: une zone de chevauchement majeur antérieure à l'accident de Sanssandra: l'exemple des régions d'Odienné et de Touba (Côte d'Ivoire)[END_REF][START_REF] Egal | Late Eburnean granitization and tectonics along the western and northwestern margin of the Archean Kenema-Man domain (Guinea West African Craton)[END_REF] (Fig. 1a). Birimian terranes of the Kédougou-Kéniéba and Kayes inliers which straddle the border between Senegal and Mali, are the westernmost exposed of the Man-Leo shield (Fig. 1).

The Paleoproterozoic "Birimian" terranes of the WAC are formed by sedimentary basins and linear to arcuate volcanic belts intruded by several generations of granitoid plutons. The accretion of these Paleoproterozoic rocks and associated granitoid plutons corresponds to the 'Eburnean orogeny' which represent a major juvenile crust-forming event. The term 'Eburnean' refers to all tectonic, metamorphic and plutonic events affecting the Birimian rocks during the Paleoproterozoic. The Paleoproterozoic rocks are dated between 2.27 Ga and 2.04 Ga [START_REF] Bonhomme | Contribution à l'étude géochronologique de la plate-forme del'Ouest Africain[END_REF][START_REF] Abouchami | A Major 2.1 Ga old event of mafic magmatism in West Africa: an early stage of crustal accretion[END_REF][START_REF] Liégeois | Short-lived Eburnian orogeny in South Mali. Geology, tectonics, U-Pb&Rb-Sr geochronology[END_REF][START_REF] Boher | Crustalgrowthin West-Africa at 2.1 Ga[END_REF]Dia et al., 1992;[START_REF] Davis | U/Pb age constraints on deposition and provenance of Birimian and goldbearingTarkwaian sediments in Ghana, West Africa[END_REF][START_REF] Hirdes | Reassessment of Proterozoic granitoid ages in Ghana on the basis of U/Pb zircon and monazite dating[END_REF][START_REF] Hirdes | Two generations of Birimian (Paleoproterozoic) volcanic belts in northeastern Cote d'Ivoire (West Africa): consequences for the 'Birimian controversy[END_REF][START_REF] Kouamelan | Reliques archéennes (3,15 Ga) au sein du magmatisme birimien (2,1 Ga) de Côte d'Ivoire, craton ouest-african[END_REF][START_REF] Doumbia | Petrogenesis of juvenile-type Birimian (Paleoproterozoic) granitoids in Central Côte-d'Ivoire, West-Africa: geochemistry and geochronology[END_REF][START_REF] Gueye | Intrusive rocks tectono-metamorphic evolution of the Mako Paleoproterozoic belt (Eastern Senegal, West Africa)[END_REF][START_REF] Masurel | The Yatela gold deposit in Mali, West Africa: The final product of a long-lived history of hydrothermal alteration and weathering[END_REF][START_REF] Parra-Avila | Crustal evolution of the Paleoproterozoic Birimian terranesof the Baoulé-Mossi domain, southern West African Craton: U-Pb and Hf-isotopestudies of detrital zircons[END_REF][START_REF] Eglinger | New insights into the crustal growth of the Paleoproterozoic margin of the Archean Kéména-Man domain, West African craton (Guinea): Implications for gold mineral system[END_REF].

A pre-Eburnean cycle in the WAC is suggested by pre-Birimian ages in the time interval of 2266 Ma and 2150 Ma which were obtained on zircon grains from different rocks (sediments, tonalites, granites) of the Man shield (Dia et al., 1992;[START_REF] Davis | U/Pb age constraints on deposition and provenance of Birimian and goldbearingTarkwaian sediments in Ghana, West Africa[END_REF][START_REF] Doumbia | Petrogenesis of juvenile-type Birimian (Paleoproterozoic) granitoids in Central Côte-d'Ivoire, West-Africa: geochemistry and geochronology[END_REF][START_REF] Doumbia | Petrogenesis of juvenile-type Birimian (Paleoproterozoic) granitoids in Central Côte-d'Ivoire, West-Africa: geochemistry and geochronology[END_REF][START_REF] Gueye | New evidences for an early Birimian evolution in the West African Craton: An example from the Kédougou-Kénieba Inlier, Southeast Sénégal[END_REF][START_REF] Perrouty | Revised Eburnean geodynamic evolution of the gold-rich southern Ashanti Belt, Ghana, with new field and geophysical evidence of pre-Tarkwaian deformations[END_REF][START_REF] Parra-Avila | Crustal evolution of the Paleoproterozoic Birimian terranesof the Baoulé-Mossi domain, southern West African Craton: U-Pb and Hf-isotopestudies of detrital zircons[END_REF]. During this period of time, two orogenic events are distinguished throughout the Birimian with different ages and terminology. In Ghana, the earlier event is referred as the Eoeburnean (2195-2150 Ma) or the Eburnean I (2266-2150 Ma) and the latter as the Eburnean (2148( -2090 Ma) Ma) or the Eburnean II (2216-2088 Ma) [START_REF] Allibone | Structural controls on gold mineralization at the Ashanti gold deposit, Obuasi, Ghana[END_REF]de Kock et al., 2011). In Burkina Faso the earlier event is the Tangaean (2170-2130 Ma) and is followed by the Eburnean (2130( -1980 Ma) Ma) [START_REF] Tshibubudze | The Markoye shear zone in NE Burkina Faso[END_REF][START_REF] Hein | Succession of structural events in the Goren greenstone belt (Burkina Faso): implications for West African tectonics[END_REF].

The Eoeburnean to Eburnean orogenies are characterized by a complex tectono-magmatic evolution [START_REF] Ledru | Tectonique transcurrente et évolution polycyclique dans le Birimien, Protérozoïque inférieur du Sénégal-Mali (Afrique de l'Ouest)[END_REF][START_REF] Ledru | Transcurrent tectonics and polycyclic evolution in the lower Proterozoic of Senegal-Mali[END_REF][START_REF] Milési | Early Proterozoic ore deposits and tectonics of the Birimian orogenic belt, West Africa[END_REF]Feybesse et al., 1994;Pons et al. 1994;[START_REF] Vidal | Evolution of a Paleoproterozoic "weak type" orogeny in the West African Craton (Ivory Coast)[END_REF][START_REF] Lompo | Paleoproterozoic structural evolution of the Man-Leo Shield (West Africa). Key structures for vertical to transcurrent tectonics[END_REF][START_REF] Dabo | Structural Styles and Tectonic evolution of the Kolia-Boboti sedimentary basin, Kédougou-Kéniéba inlier, eastern Senegal[END_REF][START_REF] Diatta | The structural evolution of the Dialé-Daléma basin, Kédougou-Kéniéba Inlier, eastern Sénégal[END_REF][START_REF] Masurel | The tectono-magmatic framework to gold mineralisation in the Sadiola-Yatela gold camp and implications for the paleotectonic setting of the Kédougou-Kénieba inlier, West Africa[END_REF]. At the scale of the WAC, they are now considered as polycyclic with two models of evolution: (i) the dome and basin geometry model which results of vertical movements due to gravitation instabilities followed by regional-scale transcurrent tectonics [START_REF] Vidal | Evolution of a Paleoproterozoic "weak type" orogeny in the West African Craton (Ivory Coast)[END_REF][START_REF] Lompo | Paleoproterozoic structural evolution of the Man-Leo Shield (West Africa). Key structures for vertical to transcurrent tectonics[END_REF][START_REF] Pitra | Palaeoproterozoic high-pressure granulite overprint of the Archean continental crust: evidence for homogeneous crustal thickening (Man Rise, Ivory Coast)[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF]; (ii) the tangential to transcurrent model with nappes stacking along orogen parallel thrust faults [START_REF] Ledru | Tectonique transcurrente et évolution polycyclique dans le Birimien, Protérozoïque inférieur du Sénégal-Mali (Afrique de l'Ouest)[END_REF][START_REF] Milési | Early Proterozoic ore deposits and tectonics of the Birimian orogenic belt, West Africa[END_REF][START_REF] Feybesse | The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling[END_REF]. This paper contributes to the details characterization of the Eoeburnean to Eburnean orogenies in the Mako Greenstone Belt southwestern part of the Kédougou-Kéniéba Inlier (KKI). The goal is to propose a tectonic evolution model based on the analyses of the field structural features.The methodology consists of cartography, detailed structural analysis of field data and satellite images, in order to better constrain the evolution of the Mako Greenstone Belt.

Geological setting

The volcanic, volcano-sedimentary and sedimentary rocks of Paleoproterozoic Birimian of the KKI are arranged into two Supergroups [START_REF] Bassot | Le complexe volcano-plutonique calco-alcalin de la rivière Daléma (Est Sénégal): discussion de sa signification géodynamique dans le cadre de l'orogénie éburnéenne (Protérozoïque inférieur)[END_REF], which are tectonically separated by the SW-NE to NS trends crustal-scale shear zone, the Main Transcurrent Zone (MTZ)(Fig. 1b). The MakoSupergroup to the west is dominantly composed of submarine volcanics, pillowed basalts, andesitic to rhyolitic flows associated with pyroclastites and ultramafic bodies. The volcano-plutonic rocks are bimodal and consist of basal tholeiitic sequence and upper calc-alkaline sequence. The tholeiitic sequence consists of pillowed and massive basalt and ultramafic bodies [START_REF] Bassot | Etude géologique du Sénégal oriental et de ses confins guinéo-maliens[END_REF][START_REF] Ngom | Caractérisation de la croûte birimienne dans les parties centrale et méridionale du Supergroupe de Mako. Implications géochimiques et pétrogénétiques[END_REF][START_REF] Dia | Isotopic constraints on the age and formation of a Palaeoproterozoic volcanic arc complex in the Kedougou inlier, eastern Senegal, West Africa[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF]. The mafic and ultramafic assemblages are petrogenetically co-magmatic [START_REF] Ngom | Caractérisation de la croûte birimienne dans les parties centrale et méridionale du Supergroupe de Mako. Implications géochimiques et pétrogénétiques[END_REF].

They show a tholeiitic affinity relative to mantle plume basalts environment [START_REF] Abouchami | A Major 2.1 Ga old event of mafic magmatism in West Africa: an early stage of crustal accretion[END_REF][START_REF] Boher | Crustalgrowthin West-Africa at 2.1 Ga[END_REF]Pawlig et al., 2006 ;[START_REF] Ngom | Sr and Nd isotopic geochemistry of the early ultramafic-mafic rocks of the Mako bimodal volcanic belt of the Kedougou-Kenieba inlier (Senegal)[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF]. The emplacement age of the mafic rocks estimated by Sm/Nd method on the whole rock (WR) is 2197±13 Ma (Dia etal., 1992).

The ultramafic rocks are not dated yet, however, they are found in inclusions within the mafic rocks and can be regarded as the base of an ophiolitic sequence characteristic of the Birimian formations of the Mako sector [START_REF] Dabo | Lithological Architecture and Petrography of the MakoBirimian Greenstone Belt, Kédougou-Kéniéba Inlier, Eastern Senegal[END_REF]. It should be noted that previous geochemical, geochronological and lithostratigraphicworks [START_REF] Dia | Caractère et signification des complexes magmatiques et métamorphiques du secteur de Sandikounda-Laminia (Nord de la boutonnière de Kédougou, Est du Sénégal): un modèle géodynamique du Birimien de l'Afrique de l'Ouest[END_REF]Bertrand etal., 1989;Dia et al., 1992) consider the amphibolitegneisses of Sandikounda-Laminia dated at 2206±6Ma (Pb/Pb on zircon, Dia et al., 1992) as the base of the Mako Supergroup.

The calc-alkaline rocks are composed of andesitic to rhyolitic flows associated with volcano-sediments (tuffs, pyroclastites, epiclastites) [START_REF] Ngom | Caractérisation de la croûte birimienne dans les parties centrale et méridionale du Supergroupe de Mako. Implications géochimiques et pétrogénétiques[END_REF][START_REF] Dia | Isotopic constraints on the age and formation of a Palaeoproterozoic volcanic arc complex in the Kedougou inlier, eastern Senegal, West Africa[END_REF]. They show a geochemical affinity of subduction zones [START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF], and of an Island-arc [START_REF] Dia | Caractère et signification des complexes magmatiques et métamorphiques du secteur de Sandikounda-Laminia (Nord de la boutonnière de Kédougou, Est du Sénégal): un modèle géodynamique du Birimien de l'Afrique de l'Ouest[END_REF]Pawlig et al., 2006 ;[START_REF] Lambert-Smith | Palaeotectonic setting of the south-eastern Kédougou-Kéniéba Inlier, West Africa: New insights from igneous trace element geochemistry and U-Pb zircon ages[END_REF]. These intermediate and felsic rocks are dated between 2160±16 Ma and 2070 Ma (Calvez et al., 1990;[START_REF] Boher | Crustalgrowthin West-Africa at 2.1 Ga[END_REF][START_REF] Hirdes | U/Pb Geochronology of Paleoproterozoic rocks in the Southern part of the Kedougou-Kéniéba inlier, Senegal, West Africa: evidence for diachronous accretionary development of the eburnean province[END_REF]. The sedimentary rocks are represented by lenses of quartzites, ribbons of limestones and of conglomerates interstratified within the mafic, intermediate and felsic rocks [START_REF] Diallo | Caractérisation, d'une portion de croûte d'âge protérozoïque inférieur du craton ouest africain: Cas de l'encaissant des granitoïdes dans le Supergroupe de Mako (boutonnière de Kédougou) -implications géodynamiques[END_REF][START_REF] Ngom | Caractérisation de la croûte birimienne dans les parties centrale et méridionale du Supergroupe de Mako. Implications géochimiques et pétrogénétiques[END_REF]. The volcano-sediments and sediments represent the top of the lithological sequence of the Mako Supergroup [START_REF] Dabo | Lithological Architecture and Petrography of the MakoBirimian Greenstone Belt, Kédougou-Kéniéba Inlier, Eastern Senegal[END_REF].

The Dialé-Daléma Supergroup is dominantly sedimentary (Table 1) and consists of interlayered pelites, sandstones, greywackes, marbles, quartzites and breccias [START_REF] Milési | Les minéralisations aurifères de l'Afrique de l'Ouest. Leurs relations avec l'évolution lithostructurale au Protérozoïque inférieur[END_REF][START_REF] Dabo | Late Eburnean deformation in the Kolia-Boboti sedimentary basin, Kédougou-Kéniéba inlier, Sénégal[END_REF]. It is represented by the upper part of the stratigraphic KKI Birimian formations [START_REF] Ngom | Sr and Nd isotopic geochemistry of the early ultramafic-mafic rocks of the Mako bimodal volcanic belt of the Kedougou-Kenieba inlier (Senegal)[END_REF]Delor et al., 2010). Geochronological data from zircons of Dialé-Daléma detrital sedimentary rocks indicate an age between 2093±7 Ma and 2165±1Ma [START_REF] Boher | Crustalgrowthin West-Africa at 2.1 Ga[END_REF][START_REF] Hirdes | U/Pb Geochronology of Paleoproterozoic rocks in the Southern part of the Kedougou-Kéniéba inlier, Senegal, West Africa: evidence for diachronous accretionary development of the eburnean province[END_REF].

The sedimentary sequence is cross-cut by a calc-alkaline volcanic complex (andesite, rhyodacite, rhyolite) which has orogenic volcanic arc affinities [START_REF] Milési | Les minéralisations aurifères de l'Afrique de l'Ouest. Leurs relations avec l'évolution lithostructurale au Protérozoïque inférieur[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF][START_REF] Lambert-Smith | Palaeotectonic setting of the south-eastern Kédougou-Kéniéba Inlier, West Africa: New insights from igneous trace element geochemistry and U-Pb zircon ages[END_REF]. Rhyolitic flow of Daléma has been dated at 2099±4 Ma [START_REF] Hirdes | U/Pb Geochronology of Paleoproterozoic rocks in the Southern part of the Kedougou-Kéniéba inlier, Senegal, West Africa: evidence for diachronous accretionary development of the eburnean province[END_REF].

Several generations of Eburnean granitoids occurred into the Birimian rocks of the KKI. They form three batholiths: Badon-Kakadian, Saraya and Boboti [START_REF] Bassot | Etude géologique du Sénégal oriental et de ses confins guinéo-maliens[END_REF]. Recent works of [START_REF] Théveniaut | Notice explicative de la carte géologique du Sénégal oriental à 1/500 000[END_REF] regard these batholiths as a suite of granitoids. They distinguish thus three suites of granitoids: Soukouta (former Badon-Kakadian batholith of [START_REF] Bassot | Etude géologique du Sénégal oriental et de ses confins guinéo-maliens[END_REF]), Saraya and Boboti. The Badon-Kakadian batholith is an assemblage of plutons mainly composed of felsic rocks, dated in the range of 2140 Ma to 2213 Ma [START_REF] Bassot | Etude géologique du Sénégal oriental et de ses confins guinéo-maliens[END_REF][START_REF] Dia | Caractère et signification des complexes magmatiques et métamorphiques du secteur de Sandikounda-Laminia (Nord de la boutonnière de Kédougou, Est du Sénégal): un modèle géodynamique du Birimien de l'Afrique de l'Ouest[END_REF][START_REF] Dia | Isotopic constraints on the age and formation of a Palaeoproterozoic volcanic arc complex in the Kedougou inlier, eastern Senegal, West Africa[END_REF][START_REF] Gueye | Intrusive rocks tectono-metamorphic evolution of the Mako Paleoproterozoic belt (Eastern Senegal, West Africa)[END_REF]. The Saraya and Boboti batholiths are composed of various granitoids (diorites, granodiorites, granites) with ages ranging between 2100-2060 Ma (Saraya) and 2080-2060 Ma (Boboti) [START_REF] Bassot | Etude géologique du Sénégal oriental et de ses confins guinéo-maliens[END_REF][START_REF] Hirdes | U/Pb Geochronology of Paleoproterozoic rocks in the Southern part of the Kedougou-Kéniéba inlier, Senegal, West Africa: evidence for diachronous accretionary development of the eburnean province[END_REF][START_REF] Théveniaut | Notice explicative de la carte géologique du Sénégal oriental à 1/500 000[END_REF][START_REF] Lambert-Smith | Palaeotectonic setting of the south-eastern Kédougou-Kéniéba Inlier, West Africa: New insights from igneous trace element geochemistry and U-Pb zircon ages[END_REF]. Recent U-Pb ages data from Boboti and Balangouma plutons in the Boboti batholith, indicate crystallization at 2088.5±8.6 Ma and 2112±13 Ma, respectively and inherited zircons in the the Boboti pluton indicatea magmatic activity in the Falémé Belt (Daléma) at 2218±83 Ma [START_REF] Lambert-Smith | Palaeotectonic setting of the south-eastern Kédougou-Kéniéba Inlier, West Africa: New insights from igneous trace element geochemistry and U-Pb zircon ages[END_REF][START_REF] Masurel | The tectono-magmatic framework to gold mineralisation in the Sadiola-Yatela gold camp and implications for the paleotectonic setting of the Kédougou-Kénieba inlier, West Africa[END_REF].

TheKKIBirimian formations are affected by a regional metamorphism of greenschist facies [START_REF] Bassot | Etude géologique du Sénégal oriental et de ses confins guinéo-maliens[END_REF]. The amphibolite facies is found in the contact aureole around some granitoid massifs [START_REF] Bassot | Etude géologique du Sénégal oriental et de ses confins guinéo-maliens[END_REF][START_REF] Dia | Caractère et signification des complexes magmatiques et métamorphiques du secteur de Sandikounda-Laminia (Nord de la boutonnière de Kédougou, Est du Sénégal): un modèle géodynamique du Birimien de l'Afrique de l'Ouest[END_REF] and associated with the ultramafic rocks particularly at Lamé sector in the SE of Mako [START_REF] Dabo | Lithological Architecture and Petrography of the MakoBirimian Greenstone Belt, Kédougou-Kéniéba Inlier, Eastern Senegal[END_REF]. At the scale of the WAC, the greenschist facies metamorphism affected most of the Birimian formations [START_REF] Debat | A new metamorphic constraint for the Eburnean orogeny from Palaeoproterozoic formations of the Man shield (Aribinda and Tampelga countries, Burkina Faso)[END_REF][START_REF] Block | Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) orogeny, NW Ghana, West African Craton[END_REF]. It resulted from a large retrograde metamorphism of amphibolite facies which are reworked to greenschist facies [START_REF] John | The metamorphic evolution of the Paleoproterozoic (Birimian) volcanic Ashanti belt (Ghana, West Africa)[END_REF][START_REF] Klemd | Metamorphism of the country rocks hosting gold-sulfide bearing quartz veins in the Paleoproterozoic southern Kibi-Winneba belt (southeast-Ghana)[END_REF][START_REF] Block | Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) orogeny, NW Ghana, West African Craton[END_REF].The greenschist to amphibolite-facies metamorphic assemblages that developed during the Eburnean orogeny are superimposed on an early thermal regime that produced high-pressure greenschist-to blueschist-facies metamorphic assemblages [START_REF] Ganne | Thermo-mechanical modelling of lower crust exhumationcontraints from the metamorphic record of the Palaeoproterozoic Eburnean orogeny, West African Craton[END_REF].

The Eburnean metamorphism is accompanied by deformation whose phases and styles are variously interpreted (Table 2). Some authors (e.g. [START_REF] Leube | The early Proterozoic Birimian Supergroup of Ghana and some aspects of its associated gold mineralization[END_REF][START_REF] Eisenlohr | The structural development of the early Proterozoic Birimian and Tarkwaian rocks of southwest Ghana, West Africa[END_REF][START_REF] Hirdes | Two generations of Birimian (Paleoproterozoic) volcanic belts in northeastern Cote d'Ivoire (West Africa): consequences for the 'Birimian controversy[END_REF][START_REF] Gasquet | Structure Sr-Nd isotope geochemistry and zircon U-Pbgeochronologyof the granitoids of the Dabakala area (Cote d'Ivoire): evidence for a 2.3 Ga crustal growth event in the Palaeoproterozoic of West Africa[END_REF] argued for a single orogenic cycle. Other authors considered a polycyclic model with two [START_REF] Ledru | Tectonique transcurrente et évolution polycyclique dans le Birimien, Protérozoïque inférieur du Sénégal-Mali (Afrique de l'Ouest)[END_REF], three [START_REF] Ouedraogo | Mise en évidence des relations entre schistosités et plissements dans la ceinture volcanique birimienne de Yako-Batié (Burkina Faso)[END_REF][START_REF] Ouedraogo | Cartographie minérale et implications métallogéniques au Burkina-Faso[END_REF]Feybesse et al., 1989[START_REF] Feybesse | The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling[END_REF][START_REF] Milési | Early Proterozoic ore deposits and tectonics of the Birimian orogenic belt, West Africa[END_REF] or more than three [START_REF] Block | Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) orogeny, NW Ghana, West African Craton[END_REF][START_REF] Block | Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) orogeny, NW Ghana, West African Craton[END_REF] major phases of Eburnean deformation with variable styles of deformation.

1-The first D 1 thrusting phase [START_REF] Feybesse | La limite Archéen-Protérozoïque inférieur de l'Afrique de l'Ouest: une zone de chevauchement majeur antérieure à l'accident de Sanssandra: l'exemple des régions d'Odienné et de Touba (Côte d'Ivoire)[END_REF][START_REF] Ledru | Tectonique transcurrente et évolution polycyclique dans le Birimien, Protérozoïque inférieur du Sénégal-Mali (Afrique de l'Ouest)[END_REF][START_REF] Ledru | Transcurrent tectonics and polycyclic evolution in the lower Proterozoic of Senegal-Mali[END_REF][START_REF] Milési | Early Proterozoic ore deposits and tectonics of the Birimian orogenic belt, West Africa[END_REF] or a peri-plutonic deformation [START_REF] Pons | Mechanism of pluton emplacement and structural evolution of 2.1Ga juvenile continental crust: the Birimian of south-western Niger[END_REF][START_REF] Vidal | Evolution géodynamique de l'Afrique de l'Ouest entre 2,2 Ga et 2 Ga: le style "archéen" des ceintures vertes et des ensembles sédimentaires birimiens du nord-est de la Côte d'Ivoire[END_REF][START_REF] Debat | A new metamorphic constraint for the Eburnean orogeny from Palaeoproterozoic formations of the Man shield (Aribinda and Tampelga countries, Burkina Faso)[END_REF][START_REF] Pitra | Palaeoproterozoic high-pressure granulite overprint of the Archean continental crust: evidence for homogeneous crustal thickening (Man Rise, Ivory Coast)[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF].

2-The second D 2 transcurrent to transpressive phase is responsible for large NS-to NE-trending Eburnean tectonic shear zones and the emplacement of several intrusions within Proterozoic terranes [START_REF] Ledru | Tectonique transcurrente et évolution polycyclique dans le Birimien, Protérozoïque inférieur du Sénégal-Mali (Afrique de l'Ouest)[END_REF][START_REF] Ledru | Transcurrent tectonics and polycyclic evolution in the lower Proterozoic of Senegal-Mali[END_REF][START_REF] Liégeois | Short-lived Eburnian orogeny in South Mali. Geology, tectonics, U-Pb&Rb-Sr geochronology[END_REF][START_REF] Pons | Kinematics of large syn-orogenic intrusions: example of the lower Proterozoic Saraya batholith (eastern Senegal)[END_REF].

3-The third D 3 phase is currently recognized in all the Birimian provinces of the WAC with variable tectonic styles: transcurrent or transtension and/or brittle ductile deformation [START_REF] Feybesse | La limite Archéen-Protérozoïque inférieur de l'Afrique de l'Ouest: une zone de chevauchement majeur antérieure à l'accident de Sanssandra: l'exemple des régions d'Odienné et de Touba (Côte d'Ivoire)[END_REF][START_REF] Feybesse | The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling[END_REF][START_REF] Ouedraogo | Mise en évidence des relations entre schistosités et plissements dans la ceinture volcanique birimienne de Yako-Batié (Burkina Faso)[END_REF][START_REF] Ouedraogo | Cartographie minérale et implications métallogéniques au Burkina-Faso[END_REF][START_REF] Dabo | Late Eburnean deformation in the Kolia-Boboti sedimentary basin, Kédougou-Kéniéba inlier, Sénégal[END_REF][START_REF] Lawrence | The geology and mineralogy of the Loulo mining district, Mali, West Africa: Evidence for two distinct styles of orogenic gold mineralization[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF]. 4-The other deformation phases are differently described throughout the WAC according to the Birimian provinces and the authors [START_REF] Block | Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) orogeny, NW Ghana, West African Craton[END_REF]Block et al., 2016).

Lithologyof the Mako area

The Mako sector, in the southern part of the Mako Supergroup (Fig. 1b), is primarily made up of ultramafic, mafic, intermediate and felsic rocks associated with some sedimentary quartzite slices (Fig. 2a). Mafic rocks are most significant and constitute the main part of the greenstone hills between Sékhoto Peul to the north and Wassadou in the south. Associated with the greenstone mafic hills appear the Lamé and Massanritana black hills that consist of ultramafic rocks, located at the east and west of Mako village, respectively. Kilometric lenses of quartzites, NNW-SSE and NE-SW oriented, are intercalated within the mafic rocks. Breccias and lavas of intermediate and felsic rocks occupy the tectonic corridors cross-cutting the previous units. Several generations of plutons (granitoids and gabbros) constitute the main part of the outcrops in Niéméniké village (Fig. 2).The NW-SE cross-section between Lamé and Sékhoto Peul (Fig. 2b), shows lateral succession of ultramafic rocks, layered metagabbros, pegmatitic metagabbros and isotropic metagabbros separated by diffuse and irregular subvertical contacts. In the mylonitic corridor of Bafoundou, the metagabbros are cross-cut by altered andesitic breccias and pass laterally to quartzites then to metabasalts in pillow lavas. The metabasalts, often pillowed, are frequent towards Sékhoto Peul. In addition, several generations of plutonic intrusions (granitoids and gabbros) with variable tectonic fabrics, are emplaced in volcanic and volcanosedimentary units between Niéméniké and Sékhoto Peul (Fig. 2).

Based on the field geometrical relationship between the different facies, [START_REF] Dabo | Lithological Architecture and Petrography of the MakoBirimian Greenstone Belt, Kédougou-Kéniéba Inlier, Eastern Senegal[END_REF] distinguished two lithological units in the Mako area: the tholeiitic ophiolitic complex at the base and the calc-alkaline mixed volcanic complex at the top, separated by lenses of quartzites (Fig. 3).

Structural features

The ophiolitic sequence and the mixed volcano-sedimentary complex of the Birimian Greenstone Belt rocks of Mako [START_REF] Ngom | Caractérisation de la croûte birimienne dans les parties centrale et méridionale du Supergroupe de Mako. Implications géochimiques et pétrogénétiques[END_REF][START_REF] Ngom | Diversité du volcanisme et évolution géodynamique au Paléoprotérozoïque: exemple du Birimien de la boutonnière de Kédougou-Kéniéba (Sénégal)[END_REF][START_REF] Dabo | Lithological Architecture and Petrography of the MakoBirimian Greenstone Belt, Kédougou-Kéniéba Inlier, Eastern Senegal[END_REF] were subject to polyphase deformations. These deformations are attributed to Eoeburnean (2195-2150 Ma) and Eburnean (2148-2060 Ma) events [START_REF] Bonhomme | Contribution à l'étude géochronologique de la plate-forme del'Ouest Africain[END_REF][START_REF] Allibone | Structural controls on gold mineralization at the Ashanti gold deposit, Obuasi, Ghana[END_REF][START_REF] Tshibubudze | The Markoye shear zone in NE Burkina Faso[END_REF][START_REF] Hein | Succession of structural events in the Goren greenstone belt (Burkina Faso): implications for West African tectonics[END_REF]de Kock et al., 2011). Three phases of deformation are distinguished, they are composed of a major (D 1 ) Eoeburnean deformation phase and two (D 2 ,D 3 ) major Eburnean deformation phases.

The Eoeburnean D 1 compressive to thrust phase

The Eoeburnean D 1 phase is a compressive deformation which reveals thrust and sinistral reverseshearing structures and large overturned folds (Figs. 4;5;6). The thrusts are the early manifestation of the D 1 phase which ends by sinistral reverse-shearing. The structures of this early deformation phase are locally preserved in certain rigid lithologies (metaperidotites, metagabbros, metabasalts and ribboned quartzites) (Figs. 5a-d). The ductile deformation structures are constituted of thrust zones, sinistral reverse-shearing, folds, L 1 stretching lineation and S 1 foliation (Figs. 4;5;6g,h).

The thrust zones and sinistral reverse-shearing are identified and characterized at the scale of the outcrops (Fig. 5). They mainly show a NE-SW direction which locally varies because of postdeformation (Eburnean). In the field, the thrust structures are poorly preserved as a result of subsequent deformation. The thrust planes are marked out by a rough N40°-45°foliation (highlighted by chlorite and sericite minerals) with a variable dip (20°-30°) towards the SE or the NW (Figs. 5b,c). The stretching lineation (L 1 ) which accompanies the displacement is hardly identifiable in the metabasalts. However, in the layers of the ribboned quartzites north of Niéméniké, it is slightly underlined by quartz-sericite minerals aggregates stretched in the N125°-25° direction along N20°-20°SE oriented foliation planes (S 1 ) (Figs. 5c,d).

The criteria of displacement associated with these thrusts are shown by the XZ foliation planes by sigma clasts and microfolds which formed at the same time as the foliation and indicate an overlapping towards the NW (Fig. 5d).

The sinistral reverse-shearing is responsible for the Massanritana metaperidotites hill displacement by more than 1 km towards the SW (Fig. 2a).The L 1 stretching lineation associated with the displacements is marked by metabasalt enclaves stretching along N110°-70 direction in the Soukourtou granodiorite (Fig. 6h).

The folding (P 1 ) related to this first deformation phase appears at various scales. In the metabasalts, the limbs of the folds (P 1 ) are highlighted by the inclination and the bending of the pillow axial planes which define a primary bedding (S o ) modeled by a buckled folding of N60°-50SE axial plane (Figs. 5e,b). In Badian, the interpillow material of the metabasalts shows a P 1 folding (Fig. 6a) which involves highstrain characters. In addition, centimetric P 1 overturned folds are also highlighted by felsic injections within metabasalts. In the metaperidotites, remnants of P 1 folds are locally observed with curvilinear axis (Fig. 6c). On the Aster satellite images, kilometric megafolds, buckled towards the NW, appear on digital terrain models (DTM) in two (2D) and three (3D) dimensions (Fig. 4). These large folds are highlighted by alternation of asymmetric hills and depressions. In the pillow-lava hills, from backlimb to forelimb, the altitude of the main axis dip of pillow bodies indicate asymmetric folding (Figs. 6c,d).

Their axes, on average NE-SW oriented, are sometimes upturned by the second post-folding P 2 (Fig. 6b).

The principal stress responsible for this Eoeburnean deformation phase would logically be oriented SE-NW taking into consideration conjugate shear joint cross-cutting the pillowed metabasalts body (Figs.

6e,f), the asymmetry of P 1 folding (Fig. 5e) as well as criteria of shearing observed in the S 1 foliation planes (Fig. 5d).

In addition, the granodiorite of Soukourtou (southern part of the Badon granodiorite) shows ptygmatitic overturned folds with N75-70SE oriented axial plane, relative to synmagmatic deformation of the D 1 phase (Fig. 6g). These folds appear also in the gneiss enclosing the granodiorite and are cross-cut by N25° oriented S 2 foliation. This granodiorite contains locally deformed metabasalt enclaves which are often stretched along the N110-40 L 1 stretching lineation (Fig. 6h). The boundaries between enclaves and granodiorite are sinuous and irregular (contact often in flower structure shape) that attests the contemporaneous emplacements between the two magmatic materials (Fig. 6h). The Badon granitoid is dated around c. 2213 Ma [START_REF] Bassot | Données géochronologiques et géochimiques nouvelles sur les granitoïdes de l'Est Sénégal: implication sur l'histoire géologique du Birrimien de cette région[END_REF][START_REF] Gueye | New evidences for an early Birimian evolution in the West African Craton: An example from the Kédougou-Kénieba Inlier, Southeast Sénégal[END_REF], i.e. during the Eoeburnian period.

Thus, the D 1 deformation is constrained by the age of emplacement of the early granitoids and metabasalts estimated by Pb/Pb methods on WR and single Zrat 2213±3 Ma and 2195±11 Ma, respectively [START_REF] Dia | Caractère et signification des complexes magmatiques et métamorphiques du secteur de Sandikounda-Laminia (Nord de la boutonnière de Kédougou, Est du Sénégal): un modèle géodynamique du Birimien de l'Afrique de l'Ouest[END_REF][START_REF] Gueye | New evidences for an early Birimian evolution in the West African Craton: An example from the Kédougou-Kénieba Inlier, Southeast Sénégal[END_REF]. This D 1 deformation would therefore be late to the emplacement of the metabasalts (≤ c. 2195 Ma) and corresponds to the Eoeburnean period. The emplacement of intermediate and felsic volcanic rocks dated at 2160±16 Ma by Sm/Nd on WR [START_REF] Boher | Crustalgrowthin West-Africa at 2.1 Ga[END_REF] marks the end of the D 1 Eoeburnean phase.

The Eburnean D 2 transpressive deformation phase

The D 2 deformation phase is well expressed in the Birimian formation of the Mako area by reverse-shear zones of variable dimensions in which foliation (S 2 ), lineation (L 2 ), and folding (P 2 ) are concentrated and revealed clearly. The semi-ductile and brittle structures (tension gashes, shear joints, rolls, fractures, faults) have a random distribution and are not always located in the shear zones.

The reverse-shear zones are oriented according to three conjugate principal directions, NNE-SSW (N20°-35°), NNW-SSE (N160°-170°) and ENE-WNW (N60°-70°)(Figs. 2a,c). A fourth direction, NS oriented, is interpreted to result from local flexure of the path of the NNE-SSW oriented shear zones (Figs. 2a;6e;7a). These shear zones are associated with three major directions of foliation S 2a (N20°-35°), S 2b (N150°-180°) and S 2c (N60°-70°) (Figs. 7b-d). The stretching lineations associated with these various shear zones show a rather moderate to steep plunge (> 35°) and a NE-SW to NW-SE and NNW-SSE direction (Fig. 7e).

The gentle ENE-WSW (N60°-70°) reverse-shear zones, with main S 2c N70°-65 SSW and minor S 2a N30°-55 SE foliations, are observed in the andesitic tuffs and ultramafic rocks of the Lamé sector. These shear zones reveal the kinematics criteria of a dextral movement (Fig. 7d) associated with the N140°-25 oriented mineral stretching lineation. In the Lamé sector the abundance of weathering surface and alluvial deposits often mask these shear zones paths and their contact with the other shear zones (NNE-SSE, NNW-SSE) which were not observed in the field. The most illustrative example of these ENE-WSW dextral reverse-shear zones is the Lamé Shear Zone (LSZ) located in the southeast of Lamé village (Fig. 2a).

The reverse-shear zones oriented NNE-SSW are more represented in the north at the Niéméniké sector (Fig. 2a). The NNE-SSW major foliation is associated with a stretching lineation of clasts along with the N100°-120° direction and dip of 25°-60° (Fig. 7e). The criteria of rotation in the XY and XZ foliation planes are clasts which indicate a sinistral reverse-shear (Figs. 7e,f).

The most important NNW-SSE (N170°) shear zone in the study area is that of Bafoundou Corridor (BC) (Fig. 2a). It is a mylonitic corridor which lengthens in the form of depression from the south of the village of Bafoundou until the north of Niéméniké on several kilometers in the NNW-SSE direction (Fig. 2a). Its lateral extension is variable and can reach 3 km locally. The principal foliation N165°-50°SW oriented (S 2b ), crenulates a former foliation (S 2a ) of N25° to N30°direction with a dip around 70°SE (Figs. 7b;8c). The criteria of shearing in the XZ and XY foliation planes (delta clasts, S/C, synfolial folds, etc.) indicate a sinistral reverse-shear (Figs. 7b,c;8c). The stretching lineation in the N160° foliation planes is roughly oriented N175°-40°.

Throughout this NNW-SSE BC mylonitic corridor most rigid facies (quartzites, metaperidotites) underwent a stretching and a boudinage accompanied by a sinistral shear on their edges (Fig. 2a). They would behave like rigid cores packed in a soft coat represented by the mylonitic facies (breccias, tuffs). Thus, the metaperidotites hill of Massanritana would have undergone at the same time as the ribboned quartzite beds of western Mako, a stretching and a boudinage accompanied by a sinistral shear in the N170° direction. On the vertical plane the conjugate NE-SW and NNW-SSE reverse faults with opposed dips, reveal locally graben structures (Figs. 8c;9a).

The P 2 folds related to the Eburnean D 2 compressive phase are mostly of modest size (metric to centimetric). They are often concentrated in the shear zones and sometimes superimposed on the P 1 folds. Thus, the gabbros and the rhyolitic tuffs of the BC shear zone show isoclinal folds (P 2 ) with tilted curved axis oriented N40°-18°and N310°-46°, respectively (Figs. 7e;9b).

In addition, on the Aster satellite images, P 2 folding appears by the bending of the P 1 folds axes (Fig. 4).

Stereoplot projection of measurements relative to the geometry of the semi-ductile to brittle structures (conjugated joints, slickenside in slip plane) indicate the NNW-SSE direction of the principal maximum stress of this phase (Figs. 6e,f;8b,c). The whole of the structures relevant to D 2 assumes a sinistral transpressive phase with a partitioning of the deformation between the mylonitic zones and the rigid cores which they pack.

The transtensive D 3 deformation phase

It is a dextral transtensional phase whose deformations are less intense than those of the former phases, primarily marked by semi-ductile and brittle structures. It appears locally by mostly dextral narrow shear zones some of which are related to a reactivation of former sinistral shear zones (Figs. 8d;9e,f). The D 3 shear zones are generally oriented NNE-SSW and NNW-SSE with a variable foliation of N20° and N150° direction cross-cutting those of the D 2 Eburnean deformation. The stretching lineation associated with this phase is seldom expressed. In the NNE-SSW shear zone affecting the mottled gabbros of Niéméniké, the lineation is underlined by the stretching of the pyroxene needles ouralitized along the N25° direction (Fig. 2a). The criteria of the movement observed in these shear zones (extrusion, folds synchronous with foliation development and clasts) reveal a dextral shear (Fig. 9f). However, the relics of a sinistral shear are still perceptible in certain NNE-SSW shear zones (Fig. 9e).

In the tuffs of Laméthe NNE-SSW foliation is affected by N160°-60°SE dextral crenulated foliation (Fig. 10a) related to D 2 phase. Also, a crenulated foliation, N160°-60°NW oriented, in a dextral shear appears locally in the pink granite of Niéméniké (Fig. 10b).

The semi-ductile deformation is demonstrated by very frequent tension gashes cross-cutting the S 2 foliation. In the quartz diorites of Niéméniké and the metabasalts in pillow lavas of western Mako appear tension gashes cross-cutting S 2 indicating a dextral shear. In the light diorite of northern Niéméniké, "en echelon" tension gashes relative to the N70°-60°SE normal fault plane appear locally (Fig. 10c).

The brittle deformation appears in the metaperidotites and the tuffs of Mako, marked by a system of conjugate normal faults oriented N140° with opposite dips (NE and SW). They involve the tilt of S 1 foliation in the form of drag fold with downthrown side indicating a collapse (Figs. 10d,e). These conjugate normal faults with opposite dips created a graben structure along the Mako village (Figs. 8d;10f). In the north of Niéméniké, the graben structure observed in the silicified metabasalts looks like a negative flower structure (Fig. 10f).

Discussion and Conclusions

The architecture of the Birimian formations of the KKI is primarily related to the Eoeburnean and Eburnean orogenesis which presents a polyphase evolution at the scale of the WAC [START_REF] Ledru | Transcurrent tectonics and polycyclic evolution in the lower Proterozoic of Senegal-Mali[END_REF][START_REF] Feybesse | The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF][START_REF] Lompo | Paleoproterozoic structural evolution of the Man-Leo Shield (West Africa). Key structures for vertical to transcurrent tectonics[END_REF][START_REF] Dabo | Structural Styles and Tectonic evolution of the Kolia-Boboti sedimentary basin, Kédougou-Kéniéba inlier, eastern Senegal[END_REF][START_REF] Baratoux | Juvenile Paleoproterozoic crust evolution during the Eburnean orogeny (~2.2-2.0 Ga), western Burkina Faso[END_REF][START_REF] Jessell | Crustal-scale transcurrent shearing in the Paleoproterozoic Sefwi-Sunyani-Comoé region, West Africa[END_REF].

Our investigations in the Mako area allowed us to distinguish three major phases of Eoeburnean (D 1 ) and Eburnean (D 2 , D 3 ) deformations evolving in different tectonic styles (Fig. 8). The D 1 phase is a compressive event which leads to thrust and sinistral reverse-shear zones. It is marked by large overturned folds towards the NW (Figs. 6c,d;8a), relics of thrust and sinistral reverse-shearing associated with stretching lineation generally oriented NW-SE with a variable dip (Fig. 2a). The principal shortening direction associated with this phase of deformation is NW-SE oriented (Figs. 6e,f;8a). These early deformation structures are filled and/or cross-cut by intermediate to acid rocks which are dated around c. 2160 Ma [START_REF] Boher | Crustalgrowthin West-Africa at 2.1 Ga[END_REF]. The high-strain folding of pillowed metabasalt and ptygmatic folding in granodiorite (Fig. 6a,g) suppose a high temperature deformation at the end of the basaltic magma cooling between 2197±13 Ma and 2195±11 Ma using Nd/Sm and Pb/Pb methods on WR, respectively [START_REF] Bassot | Données géochronologiques et géochimiques nouvelles sur les granitoïdes de l'Est Sénégal: implication sur l'histoire géologique du Birrimien de cette région[END_REF][START_REF] Dia | Caractère et signification des complexes magmatiques et métamorphiques du secteur de Sandikounda-Laminia (Nord de la boutonnière de Kédougou, Est du Sénégal): un modèle géodynamique du Birimien de l'Afrique de l'Ouest[END_REF][START_REF] Gueye | New evidences for an early Birimian evolution in the West African Craton: An example from the Kédougou-Kénieba Inlier, Southeast Sénégal[END_REF]. Therefore, the D 1 deformation phase is believed to have began around c. 2195Ma, after the emplacement of the pillowlavas basalts. This period of time corresponds to the early Paleoproterozoic event which age and terminology differs throughout the Birimian. In Ghana, the earlier event is referred as Eburnean I (2266-2150 Ma) [START_REF] Allibone | Structural controls on gold mineralization at the Ashanti gold deposit, Obuasi, Ghana[END_REF] or as Eoeburnean (2195-2150 Ma) (de Kock et al., 2011). In Burkina Faso, the early Paleoproterozoic event is the Tangaean which corresponds to the period between2170 Ma and 2130 Ma [START_REF] Tshibubudze | The Markoye shear zone in NE Burkina Faso[END_REF][START_REF] Hein | Succession of structural events in the Goren greenstone belt (Burkina Faso): implications for West African tectonics[END_REF]. In the Birimian of the KKI, [START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF] revealed an early Eburnean phase of gravity deformation (Dg) related to Eoeburnean diapirism associated with the plutonism of the Sandikounda-Soukouta Suites.

Our interpretation is that in the Mako area of KKI, the early Eoeburnean deformation (D 1 ), characterized by thrust to sinistral reverse-shear deformation is associated with large overturned folds and a regional NNW-SSE shortening that occurred at approximately 2.19-2.17Ga.

An early Eburnean compressive to thrust deformation, i.e. D 1 deformation phase, was announced in the sedimentary Birimian formations of the Dialé-Daléma Supergroup [START_REF] Ledru | Tectonique transcurrente et évolution polycyclique dans le Birimien, Protérozoïque inférieur du Sénégal-Mali (Afrique de l'Ouest)[END_REF][START_REF] Milési | Early Proterozoic ore deposits and tectonics of the Birimian orogenic belt, West Africa[END_REF][START_REF] Dabo | Structural Styles and Tectonic evolution of the Kolia-Boboti sedimentary basin, Kédougou-Kéniéba inlier, eastern Senegal[END_REF]. The age of this early Eburnean deformation is not specified in this Supergroup.

In the Birimian formations of Ghana, a D 1 -thrust deformation with SW vergence [START_REF] Feybesse | The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling[END_REF] associated with reverse shear zone and large scale folds (Block et al., 2016), similar to those of Mako, is reported in the D 1 Eburnean phase.

The Eoeburnean event has variably characteristics through the WAC. In Ghana, it reveals the development of regional scale folds and bedding parallel foliation, associated with the development of east-west trending structures during a regional north-south shortening [START_REF] Perrouty | Revised Eburnean geodynamic evolution of the gold-rich southern Ashanti Belt, Ghana, with new field and geophysical evidence of pre-Tarkwaian deformations[END_REF]. In Burkina Faso, the Tangaean event (2170-2130 Ma) is characterized by northwest to north-northwest trending dextral-reverse shear zones, and fold-thrust belts that developed during a period of northeast-southwest crustal shortening [START_REF] Tshibubudze | The Markoye shear zone in NE Burkina Faso[END_REF][START_REF] Hein | Succession of structural events in the Goren greenstone belt (Burkina Faso): implications for West African tectonics[END_REF].

The late stage of the D 1 deformation phase is marked by the emplacement of intermediate and felsic volcanic rocks which are dated around c. 2160 Ma [START_REF] Boher | Crustalgrowthin West-Africa at 2.1 Ga[END_REF].

In NW of Ghana, the N-S extensional deformation followed the D 1 Eburnean phase (Block et al., 2016).

According to [START_REF] Feybesse | The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling[END_REF], this period of extensional tectonic precedes or was partly contemporaneous with the first Eburnean deformation phase in Ghana.

The structures of the Eoeburnean phase are generally disturbed and overturned by the Eburnean deformations (Fig. 8b). The Eburnean D 2 phase of deformation is a transpressive tectonics which revealed sinistral NNE-SSW and NNW-SSE,and dextral ENE-WSW conjugate reverse-shear zones (Fig. 8c'). These NNW-SSE and NNW-SSE shears may have played the part of R and P structures in a NS oriented Riedel system where ENE-SSW shears represent the R' structures (Fig. 8c').

The principal shortening is NNW-SSE oriented according to brittle structures geometries (Figs. 9c,d; 8d'). In the course of the deformation the NNW-SSE oriented sinistral reverse-shear zones which crosscut the preceding ones (NNE-SSW), involve a flexure of their ends according to a N-S direction (Fig. 7a).

The anastomosed interconnection of very deformed shear zones (NNE-SSW and NNW-SSE) which frame the cores of little-deformed rocks results in the deformation partitioning. This Eburnean D 2 phase is similar to those described in the Dialé-Daléma Supergroup [START_REF] Ledru | Tectonique transcurrente et évolution polycyclique dans le Birimien, Protérozoïque inférieur du Sénégal-Mali (Afrique de l'Ouest)[END_REF][START_REF] Dabo | Structural Styles and Tectonic evolution of the Kolia-Boboti sedimentary basin, Kédougou-Kéniéba inlier, eastern Senegal[END_REF] as well as in the Birimian of Burkina Faso [START_REF] Block | Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) orogeny, NW Ghana, West African Craton[END_REF][START_REF] Tshibubudze | The relative and absolute chronologyofstratotectonic events in the Gorom-Gorom granitoid terrane and Oudalan-Gorouol belt, northeast Burkina Faso[END_REF] and Ghana [START_REF] Feybesse | The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling[END_REF].

Throughout the WAC the age of the early Eburnean deformation phase (denoted here D 2 ) is estimated between 2140 Ma and 2100 Ma contemporaneously with the emplacement of the syntectonic Eburnean granitoids dated between c. 2142 Ma and c. 2102 Ma [START_REF] Bassot | Données géochronologiques et géochimiques nouvelles sur les granitoïdes de l'Est Sénégal: implication sur l'histoire géologique du Birrimien de cette région[END_REF][START_REF] Liégeois | Short-lived Eburnian orogeny in South Mali. Geology, tectonics, U-Pb&Rb-Sr geochronology[END_REF][START_REF] Dia | Isotopic constraints on the age and formation of a Palaeoproterozoic volcanic arc complex in the Kedougou inlier, eastern Senegal, West Africa[END_REF]Hirdesand Davis, 2002;[START_REF] Gueye | New evidences for an early Birimian evolution in the West African Craton: An example from the Kédougou-Kénieba Inlier, Southeast Sénégal[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF][START_REF] Goujou | Notice explicative de la cartegéologique à 1/200 000 du Sénégal, feuille Kossanto-Dalafi Est[END_REF][START_REF] Block | Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) orogeny, NW Ghana, West African Craton[END_REF][START_REF] Lambert-Smith | Palaeotectonic setting of the south-eastern Kédougou-Kéniéba Inlier, West Africa: New insights from igneous trace element geochemistry and U-Pb zircon ages[END_REF].

The Eburnean D 3 phase is a dextral transtension mainly with semi-ductile and brittle structures. It is characterized by narrow shear zones NNE-SSW and NNW-SSE oriented with dextral movement. Some of these shear zones could result from a reactivation of D 2 sinistral reverse-shear zones (Figs. 9e,f). The other structures of this phase are the graben structures which result from a set of conjugate normal faults (Figs. 10d-f). The principal shortening responsible for these deformations is inferred to be oriented d). All these Eburnean structures of the D 3 deformation phase indicate a less intense deformation than those of the Eburnean D 1 and D 2 deformation phases and characterize a dextral transtension.

The Eburnean D 3 deformation probably occurred between 2100 Ma and 2060 Ma associated with the emplacement of the syntectonic granitoids of Saraya and Boboti Suite which are dated between 2100 Ma and 2060 Ma [START_REF] Abouchami | A Major 2.1 Ga old event of mafic magmatism in West Africa: an early stage of crustal accretion[END_REF][START_REF] Hirdes | U/Pb Geochronology of Paleoproterozoic rocks in the Southern part of the Kedougou-Kéniéba inlier, Senegal, West Africa: evidence for diachronous accretionary development of the eburnean province[END_REF][START_REF] Gueye | New evidences for an early Birimian evolution in the West African Craton: An example from the Kédougou-Kénieba Inlier, Southeast Sénégal[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF].

In the Dialé-Daléma Supergroup, the D 3 Eburnean deformation characterized by different structures with local reactivation of old D 2 sinistralshear zones [START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF][START_REF] Dabo | Late Eburnean deformation in the Kolia-Boboti sedimentary basin, Kédougou-Kéniéba inlier, Sénégal[END_REF][START_REF] Lawrence | The geology and mineralogy of the Loulo mining district, Mali, West Africa: Evidence for two distinct styles of orogenic gold mineralization[END_REF]. At the scale of the KKI, [START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF] distinguished an Eburnean D 3 transcurrent phase (Dt 3 ) characterized by conjugate zones of NE-SW dextral and NW-SE sinistral shears.

In the other Birimian provinces of the WAC, the Eburnean D 3 phase is also less intense than the former Eburnean phases [START_REF] Feybesse | The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling[END_REF][START_REF] Lompo | Paleoproterozoic structural evolution of the Man-Leo Shield (West Africa). Key structures for vertical to transcurrent tectonics[END_REF][START_REF] Baratoux | Juvenile Paleoproterozoic crust evolution during the Eburnean orogeny (~2.2-2.0 Ga), western Burkina Faso[END_REF]. In Ghana, it involves major ENE-SSW to minor WNW-ESE dextral shear zones with a local reactivation into dextral of the old NE-SW sinistral shear zones [START_REF] Feybesse | The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling[END_REF]. In Burkina Faso, it is marked either by thrusts with northern or southern dip and an E-W crenulation foliation associated with kink folds [START_REF] Baratoux | Juvenile Paleoproterozoic crust evolution during the Eburnean orogeny (~2.2-2.0 Ga), western Burkina Faso[END_REF] or by a transtension with dominant NE-SW dextral shear faults [START_REF] Lompo | Paleoproterozoic structural evolution of the Man-Leo Shield (West Africa). Key structures for vertical to transcurrent tectonics[END_REF].

Thus, the Mako sector in line with many Birimian provinces of the WAC is marked by a polyphase Eoeburnean to Eburnean deformations. The Eoeburnean began with compression which leads to thrusts towards the southwest associated with a sinistral reverse shearing (D 1 ) and subsequently the emplacement of intermediate to felsic volcanic rocks at around c. 2.16 Ga. The Eburnean event is marked by a sinistral transpression with NNE-SSW shortening direction (D 2 ) followed by dextral transtension with ENE-WSW shortening direction (D 3 ). Plutonic intrusions emplaced before and during the Eburnean deformation phases, i.e. between 2213 Ma and 2060 Ma [START_REF] Abouchami | A Major 2.1 Ga old event of mafic magmatism in West Africa: an early stage of crustal accretion[END_REF]Dia et al. 1992;[START_REF] Hirdes | U/Pb Geochronology of Paleoproterozoic rocks in the Southern part of the Kedougou-Kéniéba inlier, Senegal, West Africa: evidence for diachronous accretionary development of the eburnean province[END_REF][START_REF] Gueye | New evidences for an early Birimian evolution in the West African Craton: An example from the Kédougou-Kénieba Inlier, Southeast Sénégal[END_REF][START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF]. The metamorphism evolves from greenschist to amphibolite facies [START_REF] Bassot | Etude géologique du Sénégal oriental et de ses confins guinéo-maliens[END_REF], Dia et al., 1992;[START_REF] Delor | Notice explicative de la carte géologique à 1/200 000 du Sénégal, feuilleSaraya-Kédougou Est[END_REF][START_REF] Dabo | Lithological Architecture and Petrography of the MakoBirimian Greenstone Belt, Kédougou-Kéniéba Inlier, Eastern Senegal[END_REF].

Tables Captions

Table 1: Lithostratigraphy of the Birimian formations of KKI from bottom to top [START_REF] Pouclet | Geodynamic setting of Birimian volcanism in central Ivory Coast (western Africa) and its place in the Paleoproterozoic evolution of the man Shield[END_REF]. (b) Simplified geological map of the Birimian of KKI (modified after [START_REF] Pons | Kinematics of large syn-orogenic intrusions: example of the lower Proterozoic Saraya batholith (eastern Senegal)[END_REF]. Rectangle delimits the study area. Bo: Boboti; Gm: Gamaye; MTZ: Main Transcurrent Zone; SMF: Senegalo-Malian Fault. [START_REF] Dabo | Lithological Architecture and Petrography of the MakoBirimian Greenstone Belt, Kédougou-Kéniéba Inlier, Eastern Senegal[END_REF]. The thickness of the facies is estimated approximatively. From bottom to top it appears a mafic ophiolitic complex mainly of tholeiitic nature, topped by mixed volcanic complex with calc-alkali trend. The unit is intruded by three generations of granitoid (early, syn-and posttectonic).

ACCEPTED MANUSCRIPT

Highlights -Paleoproterozoic rocks of KKI were affected by Eoeburnean and Eburnean orogenic events with three deformation Phases.

-The Eoeburnean events are characterized by a compressive D1 phase.

-Age of D1 deformation deduced from emplacement of metabasalts in pillow lavas and the Badon granodiorite (c. 2198 Ma) -The Eburnean event is marked by two deformation phases: transpressional D2 followed by transtensional D3.

Figures captions Figure 1 :

 captions1 Figures captionsFigure 1: Kédougou-Kéniéba Inlier (KKI) in the Man shield, southern part of the West African Craton (WAC). (a) Schematic map of the major Precambrian greenstone belts of the southern part of the WAC (simplified from Pouclet et al., 2006). (b) Simplified geological map of the Birimian of KKI

Figure 2 :

 2 Figure 2:(a) Geological map of the Mako Paleoproterozoic Greenstone Belt (modified after Dabo et al., 2017): BC: BafoundouCorridor; LSZ: Lamé Shear Zone; MSZ: Mako Shear Zone. (b) Geological

Figure 3 :

 3 Figure 3: Schematic lithostratigraphic column of the Paleoprotezoic formations of the Mako sector

Figure 4 :

 4 Figure 4: Aster radar image of Mako sector showing (a) in two (2D) dimensions orientation of the features and the rose diagram of the different directional features; (b) in three (3D) dimensions the morphological aspect with large overturned folds (P 1 ) whose hinges are re-folded (P 2 ). (c) and (d) correspond to the location of images of Figs. 6c,d. TH:Trace of syncline hinges.

Figure 5 :

 5 Figure 5:(a) Pillowed metabasalts affected by a thrust fault, (b) and foliationS 1 affecting the normal limb of the overturned P 1 large fold within the metabasalts in pillows lavas. (c) Equal area projection, lower hemisphere, showing the position of the stretching lineation L 1 within S 1 foliation. (d) S 1 foliation, stretching lineation L 1 (underlined by stretched pebbles and recrystallization of fine quartz grains along L 1 in the microphoto) and sigma clasts indicating a SE-NW overlapping in the quartzites. (e) Overturned bending P 1 folds affecting the metabasalts in pillow lavas. Cl: clast; TF: Thrust Fault.

Figure 6 :

 6 Figure 6:(a) Metabasalts in pillow lavas showing high strain P 1 folds. (b) P 1 foldswith curved axis in the metaperidotites. (c,d) Arcuate and flatteningpillow lavas affected by P 1 mega-folds in the forelimb (c) and backlimb (d) of metabasalthills. (e) Metabasalts in pillow lavas flattened and affected by shear joints and conjugate tension gashed indicating an NW-SE principal stress. (f) Equal area projection, lower hemisphere, showing conjugate shear fractures and their relation to the position of the principal stress. (g) Ptygmatic overturned folds highlighted by leucosome facies in the granodiorite of Soukourtou and cross-cut by S 2 foliation. (h) Metabasalt enclaves in Soukourtou granodiorite showing flower structure border (Cf) and locally stretched along L 1 stretching lineation direction.

Figure 7 :

 7 Figure 7:(a) Bending of the trajectory of a NE-SW shear zone along with the N-S direction.(b) NW-SE shear zone affecting the tuffs of Bafoundou and showing two directions of foliation (S 2a , S 2b ) and a stretching lineation L 2 underlined by the micro-pebbles stretching. (c) Shear zone showing a foliation S 1 -S 2 and a sinistral movement underlined by the bending of the pillow lavas. (d) S 2a foliation crenulated by S 2c foliation in the andesitic tuffs of Lamé. (e) Rhyolitic tuffs affectinga thrust-shear highlighted by a synkinematic fold (P 2 ) of the sinistral shear (XZ plane), stretching lineation (f) and delta clasts (XY plane) indicating a NE vergence.

Figure 8 :

 8 Figure 8: Schematic block diagram of the structural evolution model of the Makosector: (a) EoeburneanD 1 phase with thrusting followed by(b) NW-SE sinistralreverse-shear zones; (c) early Eburnean D 2 phase which occured after emplacement of intermediate to felsic rocks and is marked

Figure 9 :

 9 Figure 9:(a) Metagabbros affected by conjugate reverse faults (RF) which shifted a quartz vein (Qv) that underlined positive flower structure shape; (b) P 2 folds with tilted and short axis affecting the metagabbros;(c) Slickenlines in fault surface (slickenside); (d) The pitch and the fault surface plotted on a stereonet (equal area, lower hemisphere) showing the orientation of the principal stress; (e) Relics of synfolial folding in sinistral NNE-SSW shear zone related to D 2 deformation phase in the silicified metabasalts. (f) This same shear zone shows also synfolial folding and boudinage of felsic intrusion along S 3 foliation direction indicating a dextral shearing (D 3 ).

Figure 10 :

 10 Figure 10:(a) S 3 foliationinvolving the S 2b foliationcrenulation in the granite of Niéméniké; (b) S 3 foliation involving the S 2 foliation crenulation in the NNW-SSE reverse-shear zone that affect the tuffs of Lamé; (c) "En-echelon" arranged extensional fractures related to normal faulting in the quartziticdiorite of Niéméniké; (d,e) Normal faults with opposite dips related to graben structure in the metaperidotites (Mp) and the tuffs (Tf); (f) Conjugate normal faults in the silicified metabasalts.

Table 2 :

 2 Eoeburnean and Eburnean deformation phases in some Birimian provinces of the WAC

Table 1 :

 1 Lithostratigraphy of the Birimian formations of KKI from bottom to top

		Bassot (1966)	Delor et al. (2010)	Ngom et al. (2011)
	Dialé-	-Granitoids	-Andesites, rhyodacites and	-Granitoids 4
	Daléma	-Flysch	volcano-sediments	-Graywackes, sandstones,
	Supergroup	-Cipolins, graywackes,	-Quartzites, sandstones	pelites
	(top)	quartzites, schists	-Graywackes, pelites, siltites	-Pyroclatics
			-Carbonates	-Andesitic flows
				-Graywackes, sandstones,
				pelites
				-Conglomerates
	Mako	-Late mafic rocks	-Volcano-sediments,	-Granitoids 2 and 3
	Supergroup	-Granitoids	sandstones, pelites and	-Volcano-sediments
	(bottom)	-Flysch and	conglomerates	-Massive felsics
		conglomerates	-Rhyolite and rhyodacite	-Massive basalts
		-Andesitics dominantly	-Basalts	-Sediments
		flows	-Ultrabasic rocks	-Granitoids 1
		-Ophiolitic rocks		-Peridotites
				-Pillowed basalts and jaspers

Table 2 :

 2 Eoeburnean and Eburnean deformation phases in some Birimian provinces of the WAC

	Authors	Study area	D 1 deformation	D 2 deformation	D 3 deformation	D 3+n deformation
	Delor et al.	Kédougou-	Eoeburnean:	Eburnean Dt 1
	(2010)	Kéniéba, SE	peri-plutonic	and Dt 2 :
		Senegal	gravity driven	transcurent
			deformations	tectonism
			(2.17-2.14 Ga)
	Feybesse et	Regional	Trust tectonism	D 2-3 strike-slip
	al. (2006)	Ghana	(2.13 -2.105 Ga)	movement
				(2.095 -1.98 Ga)
	Block et al.	NW Ghana	NS horizontal	NS extensional	EW shortening	D 4 -D 7	narrow
	(2015)		shortening with	shearing	and N to NNE	shear zones in
			reverse shear zones		stretching	dominantly
						transcurrent
						regime

Acknowledgments

This paper benefited from careful and constructive comments from L. Baratoux, N. Thébaud and an anonymous referee. This is an IGCP638 contribution.