The Pan-African Biotite-Muscovite Granite and Amphibole-Biotite Granite of Doua (Central Cameroon): Zircon Features, LA-MC-ICP-MS U-Pb Dating and Implication on Their Tectonic Setting

Amadou Diguim Kepnamou¹, Ganwa Alembert Alexandre^{1, 2,} , Klötzli Urs², Hauzenberger Christoph³, Ngounouno Ismaïla¹ and Naïmou Seguem^{1, 4}

¹Department of Earth Sciences, Faculty of Sciences, University of Ngaoundere, PoBox 454 Ngaoundere, Cameroon

²Labor für Geochronologie, Department für Lithosphärenforschung, Universität Wien, Althanstrasse 14, 1090 Wien, Austria

³Institut für Erdwissenschaften, Bereich Mineralogie & Petrologie, A-8010 Graz, Universitätsplaz 2/2.Stock, Austria

⁴Department of Geology, Faculty of Sciences and Techniques, University Adam Barka of Abeche, Abeche, Chad

Cite this paper

Amadou Diguim Kepnamou, Ganwa Alembert Alexandre, Klötzli Urs, Hauzenberger Christoph, Ngounouno Ismaïla and Naïmou Seguem. The Pan-African Biotite-Muscovite Granite and Amphibole-Biotite Granite of Doua (Central Cameroon): Zircon Features, LA-MC-ICP-MS U-Pb Dating and Implication on Their Tectonic Setting. Journal of Geosciences and Geomatics. 2017; 5(3):119-129. doi: 10.12691/JGG-5-3-3

Abstract

The Doua area belongs to the Adamawa-Yadé domain (AYD) of the Central African Fold Belt (CAFB) in Cameroon. It is crossed by the Central Cameroonian Shear Zone (CCSZ). The purpose of this research is to determine the tectonic setting of granites of the studied area, based on their petrography, zircons feature and their ages. Petrographicaly, the Doua area is made up of plutonic rocks hosted in an ortho or paraderivative metamorphic basement. Amphibole-biotite granite (ABG) and biotite-muscovite granite form hills and crop out on the hill side, as flagstones in the valley or river bed, and as huge blocks. Amphibole-biotite granite is granular in texture and made up of amphibole, biotite, feldspar, accessory minerals (Sphene, zircon, and apatite) and secondary minerals (sericite). Biotite-muscovite granite (BMG) is granular to granular porphyritic in texture, made up of biotite, muscovite, plagioclase, K-feldspar, quartz, accessory minerals (zircon, opaques minerals) and secondary minerals (chlorite, sericite). ABG show elongated zircon grains with well-developed magmatic oscillatory zonation. LA-ICP-MS U-Pb data from these zircons define a concordia age of 607 ± 3 Ma and considered as crystallization age of the granite. BMG shows zircon with various shape and various internal structures (oscillatory zonation, sector zonation, blurred oscillatory zonation …) which are divided into two sets. The first set regarded as xenocryst from Paleoproterozoic granitoids emplaced at 2126 ±36 Ma or from sediments which detritus comes from such granitoids. The second set of zircons shows effects of recent lead lost and a subconcordant U-Pb age of 646 ± 39 Ma . ABG was emplaced during the D3 deformational phase, date at 607 ± 3 Ma , while BMG was trigger because of syn-D1 activity of the CCSZ at 647 ±46 Ma in association with the collisional process.

Keywords

zircon features, U-Pb ages, granites, Doua, continental collision, central african fold belt

Copyright

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References

[1]	Ganwa, A.A. (2005). Les granitoïdes de Méiganga: étude pétrographique, géochimique, structurale et géochronologique. Leur place dans la chaîne panafricaine. Thèse de doctorat d’Etat, Univ. Ydé I, 162p.
[2]	Ganwa, A.A., Frisch, W., Siebel, W., Ekodeck, G.E., Shang Kongyuy, C., Ngako, V. (2008). Archean inheritances in the pyroxene–amphibole-bearing gneiss of the Méiganga area (Central North Cameroon): Geochemical and 207Pb/206Pb age imprints. Comptes Rendus Geoscience, 340, 211-222.
[3]	Ganwa, A.A., Siebel, W., Frisch, W., Shang Kongnyuy, C. (2011a): Geochemistry of magmatic rocks and time constraints on deformational phases and shear zone slip in the Méiganga area, central Cameroon. International Geology Review, Vol. 33, N° 7, June 2011, 759-784.
[4]	Ganwa, A. A., Siebel, W., Frisch, W., Shang, C. K. and Ekodeck, G. E. (2011b). Geochemistry and geochronology of the Méiganga metadiorite: implications on the timing of D2 deformational phase in Adamawa Yadé Domain in Cameroon. Int. J. Biol. Chem. Sci. 5(4): 1754-1767, August 2011.
[5]	Ganwa, A.A., Klötzli, U.S., Hauzenberger, C. (2016). Evidence for Archean inheritance in the pre-Panafrican crust of Central Cameroon: Insight from zircon internal structure and LA-MCICP-MS U-Pb ages. Journal of African Earth Sciences 120 (2016) 12-22.
[6]	Hoskin, P.W.O., Black, L.P. (2000). Metamorphic zircon formation by solid-state recrystallization of protolith igneous zircon. J. Metamorph. Geol. 18, 423e439.
[7]	Klötzli, E., Klötzli, U.,Kosler, J. (2007). A possible laser ablation xenotime U–Pb age standard: reproducibility and accuracy. Geochimica et Cosmochimica Acta 71, A495-A495.
[8]	Klötzli, U., Klötzli, E, Günes, Z. and Kosler, J. (2009). Accuracy of Laser Ablation U-Pb Zircon Dating: Results from a Test Using Five Different Reference Zircons. Geostandards and Research Geoanalytical, Vol.33, N°1, 5-15.
[9]	Lasserre, M. (1961). Etude géologique de la partie orientale de l’Adamaoua (Cameroun Central) et les principales sources minéralisées de l’Adamaoua. Bulletin de la Direction des Mines et Géologie du Cameroun, 4: 131p.
[10]	Le Fort, P. (1981). Manaslu leucogranite: a collision signature of the Himalaya. A model for its genesis and emplacement. J. Geophys. Res. 86, 10545-iO568.
[11]	Ludwig, K.R. (2003). User’s manual for Isoplot/Ex version 3.00, a geochronological toolkit for Microsoft Excel. Berkeley Geochronology Center Special Publications, 4, 72pp.
[12]	MCKENZIE, C.B. & CLARKE, D.B. (1975). Petrology of the South Mountain Batholith, Nova Scotia. Can. J. Earth Sci. 12, 1209-1218.
[13]	Naïmou Seguem, Ganwa, A.A., Klötzli, U., Diguim Kepnamou, A., Ekodeck, G.E. (2014). Petrography and Geochemistry of Precambrian Basement Straddling the Cameroon-Chad Border: The Touboro Baïbokoum Area. International Journal of Geosciences, 2014, 5, 418-431.
[14]	Ngako, V., Affaton, P., Njonfang, E. (2008). Pan-African tectonics in northwestern Cameroon: Implication for the history of western Gondwana. Gondwana Research 14 (2008) 509-522.
[15]	Ngako, V., Affaton, P., Njonfang, E. (2009). Reply Pan-African tectonics in northwestern Cameroon: Implication for the history of western Gondwana. Gondwana Research 16 (2009) 165-166.
[16]	Ngnotué, T., Nzenti, J.P., Barbey, P., Tchoua, F.M., 2000. The Ntui Bétamba high-grade gneisses: a northward extension of the panafrican Yaoundé gneisses in Cameroon. Journal of African Earth Sciences 31, 369-381.
[17]	Njanko, T., Nédélec, A., Affaton, P. (2006). Synkinematic high-K calc-alkaline plutons associated with the Pan-African Central Cameroon Shear Zone (WTibati area): petrology and geodynamic significance. Journal of African Earth Sciences 44, 494-510.
[18]	Nzenti, J.P. (1994). L’Adamaoua panafricain (région de Banyo) une zone clé pour un modèle géodynamique de la chaîne panafricaine nord équatoriale au Cameroun. Thèse Doct. d’Etat Univ.Cheick Anta Diop-Univ de Nancy I.176p.
[19]	Nzenti, J.P., Kapajika, B., Wörner, G., Lubala, T.R., (2006). Synkinematic emplacement of granitoids in a Pan-African shear zone in Central Cameroon. Journal of African Earth Sciences 45, 74-86.
[20]	Penaye, M.P., Toteu, S.F., Michard, A., Bertrand, J.M. And Dautel, D. (1989). Reliques granulitiques d´âge Protérozoïque inférieur dans la zone mobile panafricaine d´Afrique Centrale au Cameroun; géochronologie U/Pb sur Zircons. Comptes Rendus de l´Académie Sciences 309, 315-318.
[21]	Penaye, J., Toteu, S.F., Van Schmus, W.R., Nzenti, J.P., (1993). U–Pb and Sm–Nd preliminary geochronologic data on the Yaoundé series, Cameroon: reinterpretation of the granulitic rocks as the suture of a collision in the “Centrafrican” belt. Comptes Rendus de l'Académie des Sciences, Paris 317, 789-794.
[22]	Penaye, J., Toteu, S.F., Tchameni, R., Van Schmus, W.R., Tchakounte, J., Ganwa, A., Miyem, D., Nsifa, E.N. (2004). The 2.1 Ga West Central African Belt in Cameroon: extension and evolution. J. Afr. Earth Sci. 39, 159-164.
[23]	Rottura, A., Caggianelli, A, Campana, R. and Del Moro, A. (1993). Petrogenesis of Hercynian peraluminous granites from the Calabrian Arc, Italy. Eur. J. Mineral. 5, 737-754.
[24]	Rubatto, D., Williams, I.S., Buick, I.S. (2001). Zircon and monazite response to prograde metamorphism in the Reynolds Range, central Australia. Contrib Mineral Petrol (2001) 140: 458-468.
[25]	Rubatto, D. (2002). Zircon trace element geochemistry: partitioning with garnet and the link between U–Pb ages and metamorphism. Chemical Geology 184 (2002) 123-138.
[26]	Rubatto, D., Hermann, J., Berger A., Engi, M. (2009). Protracted fluid-induced melting during Barrovian metamorphism in the Central Alps. Contrib Mineral Petrol (2009) 158: 703-722.
[27]	Sláma, J., Kosler, J., Condon, D.J., Crowley, J.L., Gerdes, A., Hanchar, J.M., Horstwood, M.S.A., Morris, G.A., Nasdala, L., Norberg, N., Schaltegger, U., Schoene, B., Tubrett, M.N. and Whitehouse, M.J. (2008). Plesovice zircon - A new natural reference material for U-Pb and Hf isotopic microanalysis. Chemical Geology, 249, 1-35.
[28]	Stacey, J. S., Kramers, J. D. (1975). Approximation of terrestrial lead isotope evolution by a two-stage model. Earth Planet. Sci. Lett. 26, 207-221.
[29]	Sylvester, P.J., Ghaderi, M. (1997). Trace element analysis of scheelite by excimer laser ablation-inductively coupled plasma-mass spectrometry (EELA-ICP-MS) using a synthetic silicate glass standard. Chemical Geology, 141, 49-65.
[30]	Tchameni, R., Pouclet, A., Penaye, J., Ganwa, A.A., Toteu, S.F. (2006). Petrography and geochemistry of the Ngaoundéré Pan-African granitoids in Central North Cameroon: Implications for their sources and geological setting. Journal of African Earth Sciences 44 (2006) 511-529.
[31]	Toteu, S.F., Macaudière, J., Bertrand, J.M., Dautel, D., 1990. Metamorphic zircons from northern Cameroon: implications for the Pan-African evolution of central Africa. Geologisch Rundschau 79, 777-786.
[32]	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, Vol. 41, No. 1, January 2004, pp. 73-85.
[33]	WHITE, A.J.R. & CHAPPELL, B.W. (1983). Granitoid types and their distribution in the Lachlan Fold Belt, southeastern Australia. Geol. Soc. Am., Mem. 159, 21-34.