The Kampti-Loropeni greenstone belt (KLB) in south-west Burkina Faso forms part of the paleoproterozoic Baoulé-Mossi domain of the West African Craton. Its lithostratigraphic chronology and magmatic sources remain insufficiently constrained. This study integrates field observations, petrography, whole-rock and trace element geochemistry, whole-rock Sm-Nd isotopes and zircon U-Pb geochronology to refine the timing and petrogenesis of the KLB suite. The KLB records a bimodal magmatic succession that comprises tholeiitic basaltic rocks in the lower sequence and subordinate cal-alkaline andesite rocks together with tonalitic to potassic granitoids. The tholeiitic rocks display broadly flat REE patterns comparable to N-MORB like island arc composition, with slight negative εNd values at 2.2 Ga (？1.2 to ？0.22) indicating a primary magma source from or in interaction with an older reworked crust or previously differentiated mantle component. Their whole-rock Sm-Nd isochron age of 2264 ± 0.1 Ma provides a timeline for the lower volcanic sequence, whereas depleted-mantle ages of 3.86 to 3.22 Ga indicate an older source history. Zircon U-Pb analyses date the crystallization of a muscovite granite at 2161 ± 2.4 Ma and a monzodiorite at 2120 ± 1.8 Ma, defining at least two generations of paleoproterozoic plutonism. These results support a multistage evolutionary model involving early tholeiitic volcanism followed by calc-alkaline plutonism consistent with subduction-related arc magmatism, mantle metasomatism and crustal assimilation during the eburnean evolution of the southern West Africa Craton.
References
[1]
Boher, M., Abouchami, W., Michard, A., Albarede, F. and Arndt, N.T. (1992) Crustal Growth in West Africa at 2.1 Ga. JournalofGeophysicalResearch: SolidEarth, 97, 345-369. https://doi.org/10.1029/91jb01640
[2]
Feybesse, J.L. and Milési, J.P. (1994) The Archaean/Proterozoic Contact Zone in West Africa: A Mountain Belt of Décollement Thrusting and Folding on a Continental Margin Related to 2.1 Ga Convergence of Archaean Cratons? PrecambrianResearch, 69, 199-227. https://doi.org/10.1016/0301-9268(94)90087-6
[3]
Hirdes, W. and Davis, D.W. (1998) First U-Pb Zircon Age of Extrusive Volcanism in the Birimian Supergroup of Ghana/West Africa. JournalofAfricanEarthSciences, 27, 291-294. https://doi.org/10.1016/s0899-5362(98)00062-1
[4]
Gasquet, D., Barbey, P., Adou, M. and Paquette, J.L. (2003) Structure, Sr-Nd Isotope Geochemistry and Zircon U-Pb Geochronology of the Granitoids of the Dabakala Area (C？te d’Ivoire): Evidence for a 2.3 Ga Crustal Growth Event in the Palaeoproterozoic of West Africa? PrecambrianResearch, 127, 329-354. https://doi.org/10.1016/s0301-9268(03)00209-2
[5]
Petersson, A., Scherstén, A., Kemp, A.I.S., Kristinsdóttir, B., Kalvig, P. and Anum, S. (2016) Zircon U-Pb-Hf Evidence for Subduction Related Crustal Growth and Reworking of Archaean Crust within the Palaeoproterozoic Birimian Terrane, West African Craton, SE Ghana. PrecambrianResearch, 275, 286-309. https://doi.org/10.1016/j.precamres.2016.01.006
[6]
Parra-Avila, L.A., Kemp, A.I.S., Fiorentini, M.L., Belousova, E., Baratoux, L., Block, S., et al. (2017) The Geochronological Evolution of the Paleoproterozoic Baoulé-Mossi Domain of the Southern West African Craton. PrecambrianResearch, 300, 1-27. https://doi.org/10.1016/j.precamres.2017.07.036
[7]
Aidoo, F., Sun, F., Liang, T. and Nude, P.M. (2020) New Insight into the Dahomeyide Belt of Southeastern Ghana, West Africa: Evidence of Arc-Continental Collision and Neoarchaean Crustal Reworking. PrecambrianResearch, 347, Article ID: 105836. https://doi.org/10.1016/j.precamres.2020.105836
[8]
Sattran, V. and Wenmenga, U. (2002) Géologie du Burkina Faso/Geology of Burkina Faso. Czech Geological Survey, 136 p.
[9]
Castaing, C., Billa, M., Milési, J.P., Thiéblemont, D., Le Mentour, J., Egal, E., et al. (2003) Notice explicative de la carte géologique et miniére du Burkina Faso à 1/1,000,000. BRGM BUMIGEB, 147.
[10]
Block, S., Ganne, J., Baratoux, L., Zeh, A., Parra‐Avila, L.A., Jessell, M., et al. (2015) Petrological and Geochronological Constraints on Lower Crust Exhumation during Paleoproterozoic (Eburnean) Orogeny, NW Ghana, West African Craton. JournalofMetamorphicGeology, 33, 463-494. https://doi.org/10.1111/jmg.12129
[11]
Bossière, G., Bonkoungou, I., Peucat, J. and Pupin, J. (1996) Origin and Age of Paleoproterozoic Conglomerates and Sandstones of the Tarkwaian Group in Burkina Faso, West Africa. PrecambrianResearch, 80, 153-172. https://doi.org/10.1016/s0301-9268(96)00014-9
[12]
Doumbia, S., Pouclet, A., Kouamelan, A., Peucat, J.J., Vidal, M. and Delor, C. (1998) Petrogenesis of Juvenile-Type Birimian (Paleoproterozoic) Granitoids in Central C？te-D’ivoire, West Africa: Geochemistry and Geochronology. PrecambrianResearch, 87, 33-63. https://doi.org/10.1016/s0301-9268(97)00201-5
[13]
Tapsoba, B., Lo, C.H., Wenmenga, U., Jahn, B.M. and Sun-Lin, C. (2013) 40Ar/39Ar Thermochronology of Paleoproterozoic Granitoids of Northeast Burkina Faso, West African Craton: Implications for Regional Tectonics. PrecambrianResearch, 235, 208-229. https://doi.org/10.1016/j.precamres.2013.06.012
[14]
Lüdtke, G., Hirdes, W., Konan, G., Koné, Y., Diarra, S. and Zamblé, Z. (1998) Géologie de la région Haute Comoé Nord, avec carte géologique au 1/100.000—Feuilles Kong (coupures 4b et 4d) et Téhini-Bouna (coupures 3a et 3d), 1ère édition. Rep. N° 112713, Arch. BGR, 157 p.
[15]
Hirdes, W., Davis, D.W., Lüdtke, G. and Konan, G. (1996) Two Generations of Birimian (Paleoproterozoic) Volcanic Belts in Northeastern C？te D’ivoire (West Africa): Consequences for the “Birimian Controversy”. PrecambrianResearch, 80, 173-191. https://doi.org/10.1016/s0301-9268(96)00011-3
[16]
Kouamelan, A.N., Djro, S.C., Allialy, M.E., Paquette, J.L. and Peucat, J.J. (2015) The Oldest Rock of Ivory Coast. JournalofAfricanEarthSciences, 103, 65-70. https://doi.org/10.1016/j.jafrearsci.2014.12.004
[17]
Kouamelan, A.N., Kra, K.S.A., Djro, S.C., Paquette, J. and Peucat, J. (2017) The Logoualé Band: A Large Archean Crustal Block in the Kenema-Man Domain (Man-Leo Rise, West African Craton) Remobilized during Eburnean Orogeny (2.05 Ga). JournalofAfricanEarthSciences, 148, 6-13. https://doi.org/10.1016/j.jafrearsci.2017.09.004
[18]
Sakyi, P.A., Manu, J., Su, B., Kwayisi, D., Nude, P.M. and Dampare, S.B. (2018) Geochemical and Sm-Nd Isotopic Evidence for the Composition of the Palaeoproterozoic Crust of the West African Craton in Ghana. GeologicalJournal, 54, 3940-3957. https://doi.org/10.1002/gj.3387
[19]
Leube, A., Hirdes, W., Mauer, R. and Kesse, G.O. (1990) The Early Proterozoic Birimian Supergroup of Ghana and Some Aspects of Its Associated Gold Mineralization. PrecambrianResearch, 46, 139-165. https://doi.org/10.1016/0301-9268(90)90070-7
[20]
Davis, D.W., Hirdes, W., Schaltegger, U. and Nunoo, E.A. (1994) U-Pb Age Constraints on Deposition and Provenance of Birimian and Gold-Bearing Tarkwaian Sediments in Ghana, West Africa. PrecambrianResearch, 67, 89-107. https://doi.org/10.1016/0301-9268(94)90006-x
[21]
Lompo, M. (2009) Geodynamic Evolution of the 2.25-2.0 Ga Palaeoproterozoic Magmatic Rocks in the Man-Leo Shield of the West African Craton. A Model of Subsidence of an Oceanic Plateau. GeologicalSociety, London, SpecialPublications, 323, 231-254. https://doi.org/10.1144/sp323.11
[22]
Lompo, M. (2010) Paleoproterozoic Structural Evolution of the Man-Leo Shield (West Africa). Key Structures for Vertical to Transcurrent Tectonics. JournalofAfricanEarthSciences, 58, 19-36. https://doi.org/10.1016/j.jafrearsci.2010.01.005
[23]
Vidal, M., Delor, C., Pouclet, A., Siméon, Y. and Alric, G. (1996) évolution 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 C？te d’Ivoire. Bulletin de la Société Géologique de France, 167, 307-319.
[24]
Nanema, M., Wenmenga, U. and Ilboudo, H. (2017) Geochemical and Geodynamic Constrain of Tholeiitic Volcanism and Related Intrusions in the Kampti Gold District, Southwest Burkina Faso: Implication for Mineral Exploration. EarthScienceResearch, 7, 76-93. https://doi.org/10.5539/esr.v7n1p76
[25]
Baratoux, L., Metelka, V., Naba, S., Jessell, M.W., Grégoire, M. and Ganne, J. (2011) Juvenile Paleoproterozoic Crust Evolution during the Eburnean Orogeny (～2.2-2.0 Ga), Western Burkina Faso. PrecambrianResearch, 191, 18-45. https://doi.org/10.1016/j.precamres.2011.08.010
[26]
Koffi, Y.H., Wenmenga, U. and Djro, S.C. (2016) Tarkwaian Deposits of the Birimian Belt of Houndé: Petrological, Structural and Geochemical Study (Burkina-Faso, West Africa). InternationalJournalofGeosciences, 7, 685-700. https://doi.org/10.4236/ijg.2016.75053
[27]
Harris, C.P., le Roux, R., Cochrane, L., Martin, A.R., Duncan, J.S., Marsh, A.P., et al. (2015) The Oxygen Isotope Composition of Karoo and Etendeka Picrites: High δ18O Mantle or Crustal Contamination? ContributionstoMineralogyandPetrology, 170, 1-24. https://doi.org/10.1007/s00410-015-1164-1
[28]
Tanaka, T., Togashi, S., Kamioka, H., Amakawa, H., Kagami, H., Hamamoto, T., et al. (2000) JNdi-1: A Neodymium Isotopic Reference in Consistency with Lajolla Neodymium. ChemicalGeology, 168, 279-281. https://doi.org/10.1016/s0009-2541(00)00198-4
[29]
Vermeesch, P. (2018) IsoplotR: A Free and Open Toolbox for Geochronology. GeoscienceFrontiers, 9, 1479-1493. https://doi.org/10.1016/j.gsf.2018.04.001
[30]
Bolhar, R., Weaver, S.D., Palin, J.M., Cole, J.W. and Paterson, L.A. (2008) Systematics of Zircon Crystallisation in the Cretaceous Separation Point Suite, New Zealand, Using U/Pb Isotopes, REE and Ti Geothermometry. ContributionstoMineralogyandPetrology, 156, 133-160. https://doi.org/10.1007/s00410-007-0278-5
[31]
Nanema, M., Koffi, H.Y. and Wenmenga, U. (2016) étude pétrochimique et géodyna-mique du complexe mafique de Yelonhira dans la zone Sud du sillon de Houndé, Burkina Faso, Afrique de l’Ouest. Afrique Science, 12, 314-333. https://www.afriquescience.net/numero.php?nid=147
[32]
Taylor, P.N., Moorbath, S., Leube, A. and Hirdes, W. (1988) Geochronology and Crustal Evolution of Early Proterozoic Granite-Greenstone Terrains in Ghana/West Africa. Abstracts, International Conference on the Geology of Ghana with Special Emphasis on Gold, Commemorating the 75th Anniversary of the Ghana Geological Survey Department, Accra, 43-45.
[33]
Cox, K.G., Bell, J.D. and Pankhurst, R.J. (1979) The Interpretation of Igneous Rocks. George, Allen and Unwin.
[34]
De la Roche, H., Leterrier, J., Grandclaude, P. and Marchal, M. (1980) A Classification of Volcanic and Plutonic Rocks Using R1R2-Diagram and Major-Element Analyses—Its Relationships with Current Nomenclature. ChemicalGeology, 29, 183-210. https://doi.org/10.1016/0009-2541(80)90020-0
[35]
Galbraith, R.F. (1990) The Radial Plot: Graphical Assessment of Spread in Ages. International Journal of Radiation Applications and Instrumentation. Part D. NuclearTracksandRadiationMeasurements, 17, 207-214. https://doi.org/10.1016/1359-0189(90)90036-w
[36]
Peucat, J.-J., Capdevila, R., Drareni, A., Mahdjoub, Y. and Kahoui, M. (2005) The Eglab Massif in the West African Craton (Algeria), an Original Segment of the Eburnean Orogenic Belt: Petrology, Geochemistry and Geochronology. PrecambrianResearch, 136, 309-352. https://doi.org/10.1016/j.precamres.2004.12.002
[37]
Labou, I., Benoit, M., Baratoux, L., Grégoire, M., Ndiaye, P.M., Thebaud, N., et al. (2020) Petrological and Geochemical Study of Birimian Ultramafic Rocks within the West African Craton: Insights from Mako (Senegal) and Loraboué (Burkina Faso) Lherzolite/Harzburgite/Wehrlite Associations. JournalofAfricanEarthSciences, 162, Article ID: 103677. https://doi.org/10.1016/j.jafrearsci.2019.103677
[38]
Vidal, M. and Alric, G. (1994) The Palaeoproterozoic (Birimian) of Haute-Comoé in the West African Craton, Ivory Coast: A Transtensional Back-Arc Basin. PrecambrianResearch, 65, 207-229. https://doi.org/10.1016/0301-9268(94)90106-6
[39]
Thieblement, D. and Tegyey, M. (1994) Geochemical Discrimination of Differentiated Magmatic Rocks Attesting for the Variable Origin and Tectonic Setting of Calc-Alkaline Magmas. Comptes rendus de l’Académie des sciences. Série 2, Earth & Planetary Sciences, 319, 87-94.
[40]
Thiéblemont, D. (1999) Discrimination entre magmatismes calco-alcalins mantellique et crustal: L’exemple des Andes. ComptesRendusdel’AcadémiedesSciences-SeriesIIA-EarthandPlanetaryScience, 329, 243-250. https://doi.org/10.1016/s1251-8050(99)80242-0
