Petrography and Geochemical Studies of Granitoids from Iro Lake South-East of Moyen Chari in Chad and Geodynamic Implication — Oak Academic Publishing
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Petrography and Geochemical Studies of Granitoids from Iro Lake South-East of Moyen Chari in Chad and Geodynamic Implication
Laboratory of Geology, Geomorphology and Teledetection, Geology Department, Faculty of Exact and Applied Sciences, University of N’Djamena, N’Djaména, Chad
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Laboratory of Hydro-Geoscience and Reservoir, Geology Department, Faculty of Exact and Applied Sciences, University of N’Djamena, N’Djaména, Chad
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Laboratory of Geology, Geomorphology and Teledetection, Geology Department, Faculty of Exact and Applied Sciences, University of N’Djamena, N’Djaména, Chad
1 Laboratory of Geology, Geomorphology and Teledetection, Geology Department, Faculty of Exact and Applied Sciences, University of N’Djamena, N’Djaména, Chad
2 Laboratory of Hydro-Geoscience and Reservoir, Geology Department, Faculty of Exact and Applied Sciences, University of N’Djamena, N’Djaména, Chad
3 Laboratory of Geology, Geomorphology and Teledetection, Geology Department, Faculty of Exact and Applied Sciences, University of N’Djamena, N’Djaména, Chad
Located in Southeastern Chad. The Iro lake offers a great opportunity for the study of Precambrian formations and their Phanerozoic cover. Pluton is a Cal-alkaline granite. Due to its geographical location and geological features, it holds crucial information for understanding the evolution of the Saharan Meta craton (central Africa), which remains poorly studied. One of the objectives is to map the formations Precambrian age in Southeastern Chad. Based on the petrographic and geochemical results, we identified granitoids of pan-African age (biotite granite, aplite granite and pegmatite granite). This Precambrian basement is covered with sedimentary formations (clays, argillites, lateritic cuirasses, etc.). The mineral assemblage is characteristic of acid rocks. Geochemistry reveals rocks with a high SiO 2 range (62% - 77%) giving sub-alkaline to calc-alkaline acid rocks with high k (4.62% to 6.39%). The granitoids are classified as S-type hyperaluminous granites. This classification is supported by the presence of peraluminous minerals (e.g., muscovite) within the Iro granitoids, which also have high (>1%). Geochemical variation within the granites is largely due to extensive crystal fractionation. The Pattern of REEs normalized to the primitive mantle shows a pronounced negative Eu anomaly, reflecting the crystallization process and fractional crystallization of plagioclase in the rock, and a positive Yb anomaly. The role of plagioclase fractionation was relatively major during the earlier intrusive stages (consistent with the presence of Eu anomalies) and slightly increased, together with biotite and K-feldspar fractionation, during the later (granitic) rock crystallization. The Pattern of the spider normalized to MORBs shows two pronounced negative anomalies in TiO 2 and Cs and a slight negative anomaly in Ba. The loss of Ba, Ti and Cs may be caused by the plagioclase fractionation, apatite and ilmenite crystal. The Ba anomaly is also controlled by the presence of K-feldspar and mica. The observed Ti anomalies are due to the fractionation of magnetite indicating a subduction environment (or remelting of a source from a subduction environment).
Goodge, J.W. and Vervoort, J.D. (2006) Origin of Mesoproterozoic A-Type Granites in Laurentia: Hf Isotope Evidence. Earth and Planetary Science Letters , 243, 711-731. https://doi.org/10.1016/j.epsl.2006.01.040
Kemp, A.I.S. and Hawkesworth, C.J. (2003) Granitic Perspectives on the Generation and Secular Evolution of the Continental Crust. Treatise on Geochemistry , 3, 349-410. https://doi.org/10.1016/b0-08-043751-6/03027-9
Heilimo, E., Elburg, M.A. and Andersen, T. (2014) Crustal Growth and Reworking during Lapland-Kola Orogeny in Northern Fennoscandia: U-Pb and Lu-Hf Data from the Nattanen and Litsa-Aragub-Type Granites. Lithos , 205, 112-126. https://doi.org/10.1016/j.lithos.2014.06.014
Taylor, S.R. and McLennan, S.M. (1985) The Continental Crust: Its Composition and Evolution. Blackwell Scientific Publications.
Hawkesworth, C.J., Dhuime, B., Pietranik, A.B., Cawood, P.A., Kemp, A.I.S. and Storey, C.D. (2010) The Generation and Evolution of the Continental Crust. Journal of the Geological Society , 167, 229-248. https://doi.org/10.1144/0016-76492009-072
White, A.J.R. and Chappell, B.W. (1983) Granitoid Types and Their Distribution in the Lachlan Fold Belt, Southeastern Australia. In: Roddick, J.A., Ed., Geological Society of America Memoirs , Geological Society of America, 21-34. https://doi.org/10.1130/mem159-p21
Chappell, B.W. and White, A.J.R. (1992) I-and S-Type Granites in the Lachlan Fold Belt. Earth and Environmental Science Transactions of the Royal Society of Edinburgh , 83, 1-26. https://doi.org/10.1017/s0263593300007720
Champion, D.C. and Chappell, B.W. (1992) Petrogenesis of Felsic I-Type Granites: An Example from Northern Queensland. Earth and Environmental Science Transactions of the Royal Society of Edinburgh , 83, 115-126. https://doi.org/10.1017/s026359330000780x
Chappell, B.W. and White, A.J.R. (1974) Two Contrasting Granite Types. Pacific Geology , 8, 173-174.
Bouyo Houketchang, M., Toteu, S.F., Deloule, E., Penaye, J. and Van Schmus, W.R. (2009) U-Pb and Sm-Nd Dating of High-Pressure Granulites from Tcholliré and Banyo Regions: Evidence for a Pan-African Granulite Facies Metamorphism in North-Central Cameroon. Journal of African Earth Sciences , 54, 144-154. https://doi.org/10.1016/j.jafrearsci.2009.03.013
Couzinié, S., Ménot, R., Doumnang, J., Paquette, J., Rochette, P., Quesnel, Y., et al . (2020) Crystalline Inliers Near Lake Iro (SE Chad): Post-Collisional Ediacaran A2-Type Granitic Magmatism at the Southern Margin of the Saharan Metacraton. Journal of African Earth Sciences , 172, Article ID: 103960. https://doi.org/10.1016/j.jafrearsci.2020.103960
Reimold, W.U. and Koeberl, C. (2014) Impact Structures in Africa: A Review. Journal of African Earth Sciences , 93, 57-175. https://doi.org/10.1016/j.jafrearsci.2014.01.008
Poulin, C., Hamelin, B., Vallet-Coulomb, C., Amngar, G., Loukman, B., Cretaux, J., et al . (2019) Unraveling the Hydrological Budget of Isolated and Seasonally Contrasted Subtropical Lakes. Hydrology and Earth System Sciences , 23, 1705-1724. https://doi.org/10.5194/hess-23-1705-2019
Bessole, B. and Trompette, R. (1980) La chaine panafricaine zone mobile d’Afrique Centrale et zone mobile soudanaise. Géologie Afrique, mÉmoire BRGM Orléans (France) 2, 397.
Castaing, C., Feybesse, J.L., Thiéblemont, D., Triboulet, C. and Chèvremont, P. (1994) Palaeogeographical Reconstructions of the Pan-African/brasiliano Orogen: Closure of an Oceanic Domain or Intracontinental Convergence between Major Blocks? Precambrian Research , 69, 327-344. https://doi.org/10.1016/0301-9268(94)90095-7
Black, M. and Kasse, Y. (1995) Mission géologique au Tchad. Rapport de mission BRGM-PNUD (Rapport inédit).
Liégeois, J.P., Latouche, L., Navez, J. and Black, R. (1994) Earth and Late Pan-African Orogenies in the Tuareg Shield: Relations with East Saharan Ghost Craton and the West African Craton. Journal of African Earth Sciences , 30, 53-54.
Toteu, S.F., Penaye, J. and Djomani, Y.P. (2004) Geodynamic Evolution of the Pan-African Belt in Central Africa with Special Reference to Cameroon. Canadian Journal of Earth Sciences , 41, 73-85. https://doi.org/10.1139/e03-079
Ngako, V. (1999) Les déformations continentales panafricaines en Afrique Centrale. Résultats d’un poinçonnement de type himalayen. Master’s Thesis, Université de Yaoundé I.
Ferré, E., Gleizes, G. and Caby, R. (2002) Obliquely Convergent Tectonics and Granite Emplacement in the Trans-Saharan Belt of Eastern Nigeria: A Synthesis. Precambrian Research , 114, 199-219. https://doi.org/10.1016/s0301-9268(01)00226-1
Schneider, J.L. and Wolff, J.P. (1992) Carte géologique et cartes Hydrogéologiques à 1/1.500.000 de la République du Tchad: Mémoire explicatif. Bureau de Recherches Géologiques et Minières.
Maurin, J. and Guiraud, R. (1993) Basement Control in the Development of the Early Cretaceous West and Central African Rift System. Tectonophysics , 228, 81-95. https://doi.org/10.1016/0040-1951(93)90215-6
Shellnutt, J.G., Lee, T.Y., Torng, P.K., Yang, C.C. and Lee, Y.H. (2016) Late Cretaceous Intraplate Silicic Volcanic Rocks from the Lake Chad Region: An Extension of the Cameroon Volcanic Line? Geochemistry , Geophysics , Geosystems , 17, 2803-2824. https://doi.org/10.1002/2016gc006298
Pouclet, A., Vidal, M., Doumnang, J.-C., Vicat, J.-P. and Tchameni, R. (2006) Neoproterozoic Crustal Evolution in Southern Chad: Pan-African Ocean Basin Closing, Arc Accretion and Late-to Post-Orogenic Granitic Intrusion. Journal of African Earth Sciences , 44, 543-560. https://doi.org/10.1016/j.jafrearsci.2005.11.019
Schneider, J. and Wolff, J. (1992) Carte géologique et cartes hydrogéologiques à 1/1 500 000 de la République du Tchad. Mémoire explicatif [Geological Map and Hydrogeological Maps at 1/1,500,000 of the Republic of Chad. Explanatory Memorandum]. Memoire Explicatif. Documents du BRGM no 209, Orleans (France), 443.
Kusnir, I. (1995) Géologie, ressources minérales et ressources en eau du Tchad; Travaux et documents scientifiques du Tchad, connaissance du Tchad. Centre National de Recherche, 115.
Gsell, J. and Sonnet, J. (1960) Carte géologique de reconnaissance au 1/500.000 et notice explicative sur la feuille Adre. Brazzaville. BRGM, 42.
Pias, J. and Barbery, J. (1965) Cartes pédologiques de reconnaissance au 1:200 000, feuille de lac Iro-Djouna. République du Tchad, 106.
Doumnang, J.C. (2006) Géologie des formations néoprotérozoïques du Mayo-Kebbi (Sud-ouest du Tchad): Apports de la pétrologie et de la géochimie, implications sur la géodynamique au Panafricain. Université d’Orléans, 86-117.
Irvine, T.N. and Baragar, W.R.A. (1971) A Guide to the Chemical Classification of the Common Volcanic Rocks. Canadian Journal of Earth Sciences , 8, 523-548. https://doi.org/10.1139/e71-055
Le Maitre et al . (1989) Download Scientific Diagram/Diagramme SiO 2 vs Na 2 O+K 2 O appliqué aux roches magmatiques du Group de Ouarzazate (NP3sW).
Rickwood, P.C. (1989) Boundary Lines within Petrologic Diagrams Which Use Oxides of Major and Minor Elements. Lithos , 22, 247-263. https://doi.org/10.1016/0024-4937(89)90028-5
Barbarin, B. (1996) Genesis of the Two Main Types of Peraluminous Granitoids. Geology , 24, 295-298. https://doi.org/10.1130/0091-7613(1996)024<0295:gottmt>2.3.co;2
Mandler, J.M., Bauer, P.J. and McDonough, L. (1991) Separating the Sheep from the Goats: Differentiating Global Categories. Cognitive Psychology , 23, 263-298. https://doi.org/10.1016/0010-0285(91)90011-c
Pearce, J.A. (1983) Role of the Sub-Continental Lithosphere in Magma Genesis at Active Continental Margins. In: Hawkesworth, C.J. and Norry, M.J., Eds., Continental Basalts and Mantle Xenoliths , Shiva Cheshire, 230-249.
Kamenetsky, V.S. (2001) Factors Controlling Chemistry of Magmatic Spinel: An Empirical Study of Associated Olivine, Cr-Spinel and Melt Inclusions from Primitive Rocks. Journal of Petrology , 42, 655-671. https://doi.org/10.1093/petrology/42.4.655
Barbarin, B. (1990) Granitoids: Main Petrogenetic Classifications in Relation to Origin and Tectonic Setting. Geological Journal , 25, 227-238. https://doi.org/10.1002/gj.3350250306
Barbarin, B. (2005) Mafic Magmatic Enclaves and Mafic Rocks Associated with Some Granitoids of the Central Sierra Nevada Batholith, California: Nature, Origin, and Relations with the Hosts. Lithos , 80, 155-177. https://doi.org/10.1016/j.lithos.2004.05.010
Barbarin, B. and Didier, J. (1992) Genesis and Evolution of Mafic Microgranular Enclaves through Various Types of Interaction between Coexisting Felsic and Mafic Magmas. Earth and Environmental Science Transactions of the Royal Society of Edinburgh , 83, 145-153. https://doi.org/10.1017/s0263593300007835
Castro, A., de la Rosa, J.D. and Stephens, W.E. (1990) Magma Mixing in the Subvolcanic Environment: Petrology of the Gerena Interaction Zone near Seville, Spain. Contributions to Mineralogy and Petrology , 106, 9-26. https://doi.org/10.1007/bf00306405
Turnbull, R., Weaver, S., Tulloch, A., Cole, J., Handler, M. and Ireland, T. (2010) Field and Geochemical Constraints on Mafic-Felsic Interactions, and Processes in High-Level Arc Magma Chambers: An Example from the Halfmoon Pluton, New Zealand. Journal of Petrology , 51, 1477-1505. https://doi.org/10.1093/petrology/egq026
Chappell, B.W. and White, A.J.R. (2001) Two Contrasting Granite Types: 25 Years Later. Australian Journal of Earth Sciences , 48, 489-499. https://doi.org/10.1046/j.1440-0952.2001.00882.x
Nesbitt, H.W., Markovics, G. and price, R.C. (1980) Chemical Processes Affecting Alkalis and Alkaline Earths during Continental Weathering. Geochimica et Cosmochimica Acta , 44, 1659-1666. https://doi.org/10.1016/0016-7037(80)90218-5
Li, J., Qian, Y., Tekoumc, L., Zhao, C., Sun, J., Zheng, T., et al . (2021) Petrogenesis of Jurassic Granitoids on Liaodong Peninsula, Northeast China: Constraints on the Evolution of the Mongol-Okhotsk and Pacific Tectonic Regimes. Journal of Earth Science , 32, 127-143. https://doi.org/10.1007/s12583-020-1372-0
Guo, Z. and Wilson, M. (2012) The Himalayan Leucogranites: Constraints on the Nature of Their Crustal Source Region and Geodynamic Setting. Gondwana Research , 22, 360-376. https://doi.org/10.1016/j.gr.2011.07.027
Harris, N.B.W., Pearce, J.A. and Tindle, A.G. (1986) Geochemical Characteristics of Collision-Zone Magmatism. Geological Society , London , Special Publications , 19, 67-81. https://doi.org/10.1144/gsl.sp.1986.019.01.04
Abdelsalam, M.G., Liégeois, J. and Stern, R.J. (2002) The Saharan Metacraton. Journal of African Earth Sciences , 34, 119-136. https://doi.org/10.1016/s0899-5362(02)00013-1
Patino Douce, A.E. and Harris, N. (1998) Experimental Constraints on Himalayan Anatexis. Journal of Petrology , 39, 689-710. https://doi.org/10.1093/petroj/39.4.689
Pin, C. and Poidevin, J. (1987) U-pb Zircon Evidence for a Pan-African Granulite Facies Metamorphism in the Central African Republic. a New Interpretation of the High-Grade Series of the Northern Border of the Congo Craton. Precambrian Research , 36, 303-312. https://doi.org/10.1016/0301-9268(87)90027-1