The Toumodi-Fetêkro region, located in the heart of the Ivorian Paleoproterozoic domain, has been the subject of numerous petrographic, structural, and geochemical studies aimed at understanding its geological evolution. These studies, mainly conducted in the central part of the Fetêkro greenstone belt, around the Toumodi region, have focused on localities such as Lomo Nord, Akakro N’zipri, Anikro-Kadjokro, Angoda, Gbonti, Loukou-Yaokro, Konan-Kokorékro, and Zaakro. The main goal of this study is to broaden the understanding of the mafic volcaniclastic deposits found in the central part of the Toumodi-Fetêkro greenstone belt, with a specific focus on their depositional context while providing detailed volcanological insights. To achieve this, we conducted comprehensive fieldwork, including geological mapping, petrographic analysis, and sedimentological studies, complemented by thin-section analyses in the laboratory. The results obtained were carefully analyzed and interpreted from a volcanological perspective. Petrographic observations revealed the presence of various volcaniclastic deposits, including breccias (both monolithological and polylithological), lapilli tuffs, and cinerites. Detailed sedimentological analysis uncovered several key structures, including cross-laminations at tight angles, large amplitude parallel laminations, and depositional features based on the Bouma and Lowe classification systems. These sedimentary structures allowed us to construct three stratigraphic logs at the Lomo Nord, Akakro N’zipri, and Anikro localities. Volcanological interpretations of these deposits suggest that they are the result of pyroclastic fallout, debris avalanche deposits, hyperconcentrated debris flow deposits, and riverine deposits. These are all secondary deposits formed in a hydrovolcanic environment, reflecting the complex interactions between volcanic activity and water. The deposits are interpreted as originating from an avalanche phase during a sectoral collapse of an unstable volcanic edifice, likely triggered by significant hydromagmatic events. This study highlights the role of volcanic instability and hydromagmatic processes in the formation of mafic volcaniclastic deposits in the central Toumodi-Fetêkro region, offering new insights into the volcanic history and geological processes of the Birimian greenstone belt.
Perinotto, H. (2014) Dynamique de mise en place des avalanches de débris sur les flancs aériens des volcans insulaires: Le cas de La Réunion. Thèse, Université Bordeaux, 323 p.
Ui, T. and Glicken, H. (2000) Debris Avalanches. In: Sigurdsson, H., Houghton, B., Rymer, H., Stix, J. and McNutt, S., Eds., Encyclopedia of Volcanoes , Academic Press, 617-626.
Doumbia, S., Pouclet, A., Kouamelan, A., Peucat, J.J., Vidal, M. and Delor, C. (1998) Petrogenesis of Juvenile-Type Birimian (Paleoproterozoic) Granitoids in Central Côte-D’ivoire, West Africa: Geochemistry and Geochronology. Precambrian Research , 87, 33-63. https://doi.org/10.1016/s0301-9268(97)00201-5
Nommade, S. (2001) Evolution géodynamique des cratons des Guyanes et d’Afrique de l’Ouest. Apport des données paléomagnétiques, géochronologiques ( 40 Ar/ 39 Ar) et géochimiques en Guyane et Côte-d’Ivoire. Thèse de Doctorat, Université d’Orléans.
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 (Côte D’ivoire): Evidence for a 2.3 Ga Crustal Growth Event in the Palaeoproterozoic of West Africa? Precambrian Research , 127, 329-354. https://doi.org/10.1016/s0301-9268(03)00209-2
Soumaila, A., Henry, P., Garba, Z. and Rossi, M. (2008) REE Patterns, Nd-Sm and U-Pb Ages of the Metamorphic Rocks of the Diagorou-Darbani Greenstone Belt (Liptako, SW Niger): Implication for Birimian (Palaeoproterozoic) Crustal Genesis. Geological Society , London , Special Publications , 297, 19-32. https://doi.org/10.1144/sp297.2
Taylor, P.N., Moorbath, S., Leube, A. and Hirdes, W. (1992) Early Proterozoic Crustal Evolution in the Birimian of Ghana: Constraints from Geochronology and Isotope Geochemistry. Precambrian Research , 56, 97-111. https://doi.org/10.1016/0301-9268(92)90086-4
Hirdes, W., Davis, D.W., Lüdtke, G. and Konan, G. (1996) Two Generations of Birimian (Paleoproterozoic) Volcanic Belts in Northeastern Côte D’ivoire (West Africa): Consequences for the “Birimian Controversy”. Precambrian Research , 80, 173-191. https://doi.org/10.1016/s0301-9268(96)00011-3
Sakyi, P.A., Kwayisi, D., Nunoo, S., Ocran, E., Su, B. and Malaviarachchi, S.P.K. (2024) Crustal Evolution of Alternating Paleoproterozoic Belts and Basins in the Birimian Terrane in Southeastern West African Craton. Journal of African Earth Sciences , 220, Article ID: 105449. https://doi.org/10.1016/j.jafrearsci.2024.105449
Bessoles, B. (1977) Géologie de l’Afrique, le craton ouest africain (Mém. B.R.G.M., Paris vol n088). Bureau de Recherches Géologiques et Minières.
Junner, N.R. (1940) The Geology of the Gold Coast and Western Togoland with Revised Geological Map (1:1,000,000). Gold Coast Geological Survey Bulletin, 11, 40 p.
Tagini, B. (1971) Esquisse structurale de la Côte d’Ivoire. Thèse de l’Université de Lausanne et publication SODEMI, 302 p.
Camil, J. (1984) Pétrographie, chronologie des ensembles granulitiques archéens et formations associées de la région de Man (Côte d’Ivoire). Implications pour l’histoire géologique du craton Ouest africain. Thèse de doctorat ès Sciences, Université d’Abidjan.
Yao, K.A. (1993) Le volcanisme du sillon de Boundiali, phénomène principal du Paléoprotérozoïque inférieur de cette région N. NW de la Côte d’Ivoire. Pétrologie, géochimie, géochronologie. Thèse, Université Clermont-Ferrand 2, 218 p.
Hurley, P.M. and Rand, J.R. (1973) Outline of Precambrian Chronology in Lands Bordering the South Atlantic, Exclusive of Brazil. In: Nairn, A.E.M. and Stehli, F.G., Eds., The South Atlantic , Springer US, 391-410. https://doi.org/10.1007/978-1-4684-3030-1_10
Mériaud, N., Thébaud, N., Masurel, Q., Hayman, P., Jessell, M., Kemp, A., et al . (2020) Lithostratigraphic Evolution of the Bandamian Volcanic Cycle in Central Côte D’ivoire: Insights into the Late Eburnean Magmatic Resurgence and Its Geodynamic Implications. Precambrian Research , 347, Article ID: 105847. https://doi.org/10.1016/j.precamres.2020.105847
Boya Tokpa, K.L.D., Adingra, M., Gnanzou, A, Gbele, O., Apo, R. and Coulibaly, Y. (2022) The Birimien Granitoids of the Toumodi-Fetekro Belt in the West Africa Craton (Côte d’Ivoire): Petrogenetic Overview and Link to Mineralization. Journal of Geosciences and Geomatics , 10, 139-152.
Le Maitre, R.W. (2002) Terminology Recommended by the International Union of Geological Sciences (IUGS) for Clastic Formations. https://doi.org/10.1017/CBO9780511535581
Voight, B., Janda, R.J., Glicken, H. and Douglass, P.M. (1983) Nature and Mechanics of the Mount St Helens Rockslide-Avalanche of 18 May 1980. Géotechnique , 33, 243-273. https://doi.org/10.1680/geot.1983.33.3.243
Glicken, H. (1996) Rockslide-Debris Avalanche of May 18, 1980, Mount St. Helens Volcano, Washington (U.S. Geological Survey Open-File Report 96-677). https://doi.org/10.3133/ofr96677
Belousov, A., Belousova, M. and Voight, B. (1999) Multiple Edifice Failures, Debris Avalanches and Associated Eruptions in the Holocene History of Shiveluch Volcano, Kamchatka, Russia. Bulletin of Volcanology , 61, 324-342. https://doi.org/10.1007/s004450050300
Siebert, L., Glicken, H. and Ui, T. (2019) Volcanic Sector Collapse and Debris Avalanches: Characteristics, Behavior, and Hazards. In: Sigurdsson, H., Ed., Encyclopedia of Volcanoes , 2nd Edition, Academic Press, 627-652.
Vallance, J.W. and Iverson, R.M. (2015) Lahars and Debris Flows from Volcanic Edifices. In: Sigurdsson, H., Ed., The Encyclopedia of Volcanoes , 2nd Edition, Academic Press, 649-664.
Thompson, N., Bennett, M.R. and Petford, N. (2009) Analyses on Granular Mass Movement Mechanics and Deformation with Distinct Element Numerical Modeling: Implications for Large-Scale Rock and Debris Avalanches. Acta Geotechnica , 4, 233-247.
Vallance, J.W. (2024) Lahars: Origins, Behavior and Hazards. In: Jakob, M., McDougall, S. and Santi, P., Eds., Advances in Debris - Flow Science and Practice , Springer International Publishing, 347-382. https://doi.org/10.1007/978-3-031-48691-3_12
Romero, J.E., Polacci, M., Watt, S., Kitamura, S., Tormey, D., Sielfeld, G., et al . (2021) Volcanic Lateral Collapse Processes in Mafic Arc Edifices: A Review of Their Driving Processes, Types and Consequences. Frontiers in Earth Science , 9, Article ID: 639825. https://doi.org/10.3389/feart.2021.639825
Siebert, L. and Roverato, M. (2020) A Historical Perspective on Lateral Collapse and Volcanic Debris Avalanches. In: Roverato, M., Dufresne, A. and Procter, J., Eds., Volcanic Debris Avalanches , Springer International Publishing, 11-50. https://doi.org/10.1007/978-3-030-57411-6_2
Davies, T., McSaveney, M. and Kelfoun, K. (2010) Runout of the Socompa Volcanic Debris Avalanche, Chile: A Mechanical Explanation for Low Basal Shear Resistance. Bulletin of Volcanology , 72, 933-944. https://doi.org/10.1007/s00445-010-0372-9
Valderrama, P., Roche, O., Samaniego, P., van Wyk de Vries, B., Bernard, K. and Mariño, J. (2016) Dynamic Implications of Ridges on a Debris Avalanche Deposit at Tutupaca Volcano (Southern Peru). Bulletin of Volcanology , 78, Article No. 14. https://doi.org/10.1007/s00445-016-1011-x
Makris, S., Manzella, I., Cole, P. and Roverato, M. (2020) Grain Size Distribution and Sedimentology in Volcanic Mass-Wasting Flows: Implications for Propagation and Mobility. International Journal of Earth Sciences , 109, 2679-2695. https://doi.org/10.1007/s00531-020-01907-8
Vallance, J.W. and Iverson, R.M. (2015) Lahars and Their Deposits. In: The Encyclopedia of Volcanoes , Elsevier, 649-664. https://doi.org/10.1016/b978-0-12-385938-9.00037-7
Thouret, J., Antoine, S., Magill, C. and Ollier, C. (2020) Lahars and Debris Flows: Characteristics and Impacts. Earth - Science Reviews , 201, Article ID: 103003. https://doi.org/10.1016/j.earscirev.2019.103003
Pothin, K.B. (1993) Un exemple de volcanisme du Protérozoïque inférieur en Côte d’Ivoire: Zone de subduction ou zone de cisaillement? Journal of African Earth Sciences ( and the Middle East ), 16, 437-443. https://doi.org/10.1016/0899-5362(93)90102-v
Vidal, M. (1987) Les déformations eburnéennes de l’unité birrimienne de la comoé (Côte d’Ivoire). Journal of African Earth Sciences (1983), 6, 141-152. https://doi.org/10.1016/0899-5362(87)90056-x
Lompo, M. (2010) Paleoproterozoic Structural Evolution of the Man-Leo Shield (West Africa). Key Structures for Vertical to Transcurrent Tectonics. Journal of African Earth Sciences , 58, 19-36. https://doi.org/10.1016/j.jafrearsci.2010.01.005
Vidal, M., Gumiaux, C., Cagnard, F., Pouclet, A., Ouattara, G. and Pichon, M. (2009) Evolution of a Paleoproterozoic “Weak Type” Orogeny in the West African Craton (Ivory Coast). Tectonophysics , 477, 145-159. https://doi.org/10.1016/j.tecto.2009.02.010
Baratoux, L., Jessell, M.W. and Kouamelan, A.N. (2024) The West African Craton. In: Hamimi, Z., et al ., Eds., The Geology of North Africa , Springer International Publishing, 47-68. https://doi.org/10.1007/978-3-031-48299-1_3
Herbosch, A., Liégeois, J., Gärtner, A., Hofmann, M. and Linnemann, U. (2020) The Stavelot-Venn Massif (Ardenne, Belgium), a Rift Shoulder Basin Ripped off the West African Craton: Cartography, Stratigraphy, Sedimentology, New U-Pb on Zircon Ages, Geochemistry and Nd Isotopes Evidence. Earth - Science Reviews , 203, Article ID: 103142. https://doi.org/10.1016/j.earscirev.2020.103142
Elsworth, D. and Voight, B. (1996) Evaluation of Volcano Flank Instability Triggered by Dyke Intrusion. Geological Society , London , Special Publications , 110, 45-53. https://doi.org/10.1144/gsl.sp.1996.110.01.03
Tibaldi, A. and Groppelli, G. (2002) Volcano-Tectonic Activity along Structures of the Unstable NE Flank of Mt. Etna (Italy) and Their Possible Origin. Journal of Volcanology and Geothermal Research , 115, 277-302. https://doi.org/10.1016/s0377-0273(01)00305-5