IJG  Vol.3 No.3 , July 2012
Geochemistry and Geochronology of Peraluminous High-K Granitic Leucosomes of Yaoundé Series (Cameroon): Evidence for a Unique Pan-African Magmatism and Melting Event in North Equatorial Fold Belt
Abstract: Geochemical and geochronological studies have been carry out on the leucosomes of Yaoundé series with the aims to identify the magma sources and to indicate their production periods and emplacement within the formations of the Pan-African North-Equatorial Fold Belt (PANEFB) in Cameroon. The Yaoundé series belongs to the Southern domain of the PANEFB and it is composed of migmatites in which two types of granitic leucosomes (in situ leucosomes and injected leucosomes) have been distinguished. These rocks display characteristic of calc-alkaline (in situ leucosomes) and high-K calc-alkaline to shoshonitic series (injected leucosomes). All the rocks are peraluminous with in situ leucosomes conform to S-type and injected leucosomes conform to I- and S-type granitoids. Major and trace elements composition reveal that in situ leucosomes derived from the partial melting of the host metapelite whereas injected leucosomes derived from the melting of metagreywacke. These sources are similar to those of granitoids from central and northern domains of the PANEFB. Th-U-Pb dating by electron microprobe (EMP) and LA-ICP-MS U-Pb dating on zircon have been used to constraints the melting event and emplacement of leucosomes in Yaoundé series. Th-U-Pb monazite dating, undertaken in two samples of leucosomes, gives two groups of monazite ages. The older group gives an age of 658 Ma whereas the age of younger group is 592 Ma. U-Pb dating of zircons from the leucosomes reveals a Pan-African age ranging from 626 to 654 Ma whereas zircons from metapelitic host rock reveal the overprinting of an early Pan-African event 911 - 1127 Ma on Palaeoproterozoic (2127 Ma) inheritance. These data clearly indicate that the host rocks of leucosomes of Yaoundé series have been firstly metamorphosed during Tonien-Stenien period (911 - 1127 Ma) and reveal the existence of extended unique melting event (592 and 658 Ma) in the Yaoundé series which is contemporaneous with the magmatism responsible for the emplacement of granitoids in the other domains of the PANEFB.
Cite this paper: N. Timoleon, G. Sylvestre, N. Paul, S. Bernhard, T. Depesquidoux I and S. Emmanuel, "Geochemistry and Geochronology of Peraluminous High-K Granitic Leucosomes of Yaoundé Series (Cameroon): Evidence for a Unique Pan-African Magmatism and Melting Event in North Equatorial Fold Belt," International Journal of Geosciences, Vol. 3 No. 3, 2012, pp. 525-548. doi: 10.4236/ijg.2012.33055.

[1]   M. Pichavent, D. J. Kontak, L., Briqueu, J. V. Herrera and A. H. Clark, “The Miocene-Pliocene Macusani Volcanic, SE Peru. II. Geochemistry and Origin of a Peraluminous Magma,” Contribution to Mineralogy and Petrology, Vol. 100, No. 3, 1988, pp. 325-338

[2]   M. Pichavent, D. J. Kontak, J. V. Herrera and A. H. Clark, “The Miocene-Pliocene Macusani Volcanic, SE Peru I. Mineralogy and Magmatic Evolution of a Two Mica Aluminosilicate Bearing Ignimbrite Suite,” Contribution to Mineralogy and Petrology, Vol. 100, No. 3, 1988, pp. 300-324.

[3]   J. P. Nzenti, E. L. T. Njiosseu and A. N. Nchare, “The Metamorphic Evolution of the Palaeoproterozoic High Grade Banyo Gneisses (Adamawa, Cameroon, Central Africa),” Journal of the Cameroon Academy of Sciences, Vol. 7, No. 2, 2007, pp. 95-109.

[4]   J. P. Nzenti, B. Abaga, C. E. Suh and C. Nzolang, “Petrogenesis of Peraluminous Magmas from the Akum-Bamenda Massif, Pan-African Fold Belt, Cameroon,” International Geology Review, Vol. 53, No. 10, 2011, pp. 1121-1149. doi:10.1080/00206810903442402

[5]   D. T. Tchato, B. Schulz and J. P. Nzenti, “Electron Microprobe (EMP) Monazite Dating and P-T Data of the Neoproterozoic Metamorphic and Mylonitic Events in the Kekem Area, Cameroon North Equatorial Fold Belt,” Neues Jahbur of Paleontology, Vol. 186, No.1, 2009, pp. 95-109.

[6]   J. P. Nzenti, P. Barbey, J. Macaudiere and D. Soba, “Origin and Evolution of the Late Precambrian High-Grade Yaoundé Gneisses (Cameroon),” Precambrian Research, Vol. 38, No. 2, 1988, pp. 91-109.doi:10.1016/0301-9268(88)90086-1

[7]   T. Ngnotué, J. P. Nzenti, P. Barbey and F. M. Tchoua, “The Ntui-Betamba High Grade Gneisse: A Northward Extension of the Pan-African Yaoundé Gneisses in Cameroon,” Journal of African Earth Sciences, Vol. 31, No. 2, 2000, pp. 369-381.

[8]   J. P. Nzenti, P. Barbey, P. Jegouzo and C. Moreau, “Un Nouvel Exemple de Ceinture Granulitique dans une Cha?ne Protérozo?que de Transition: Les Migmatites de Yaoundé au Cameroun,” Compte Rendu Académie des Sciences de Paris, Vol. 299, No. 17, 1984, pp. 1197-1199

[9]   J. Penaye, S. F. Toteu, W. R. Van Schmus and J. P. Nzenti, “U-Pb and Sm-Nd Preliminary Geochronology Data on the Yaoundé Series, Cameroon: Re-Interpretation of the Granulitic Rocks as the Suture of Collision in the ‘Centrafrican’ Belt,” Comptes Rendus de l’Académie des Sciences de Paris, Vol. 317, No. 2, 1993, pp. 789-794.

[10]   S. F. Toteu, W. R. Van Schmus, J. Penaye and J. B. Nyobe, “U-Pb and Sm-Nd Evidence of Eburnian and Pan-African High Grade Metamorphism in Cratonic Rocks of Southern Cameroon,” Precambrian Research, Vol. 67, No. 3-4, 1994, pp. 321-347.doi:10.1016/0301-9268(94)90014-0

[11]   S. Owona, B. Schulz, L. Ratschbacher, J. M. Ondoa, G. E. Ekodeck, F. M. Tchoua and P. Affaton, “Pan-African Metamorphic Evolution in the Southern Yaoundé Group (Oubanguide Complex, Cameroon) as Revealed by EMP Monazite Dating and Thermobarometry of Garnet Metapelites,” Journal of African Earth Sciences, Vol. 59, No. 1, 2010, pp. 125-139. doi:10.1016/j.jafrearsci.2010.09.003

[12]   J. P. Nzenti, “Pétrogenèse des Migmatites de Yaoundé (Cameroun): Eléments pour un Modèle Géodynamique de la Cha?ne Panafricaine Nord-Equatoriale,” These Doc- torat, University of Nancy I, Nancy, 1987.

[13]   P. Barbey, J. Macaudière and J. P. Nzenti, “High-Pressure Dehydration Melting of Metapelites: Evidence from Migmatites of Yaoundé (Cameroon),” Journal of Petrology, Vol. 31, No. 2, 1990, pp. 401-428.

[14]   V. Ngako, “Evolution Métamorphique et Structurale de la Bordure Sud-Ouest de la ‘Série de Poli’, Segment Camerounais de la Cha?ne Panafricaine,” Mémoire et documents du C.A.E.S.S., Vol. 5, 1986, 185 p.

[15]   S. F. Toteu, A. Michard, J. M. Bertrand and G. Rocci “U/Pb of Precambrian Rocks from Northern Cameroon, Orogenic Evolution and Chronology of the Pan-African Belt of Central Africa,” Precambrian Research, Vol. 37, No. 1, 1987, pp. 71-87. doi:10.1016/0301-9268(87)90040-4

[16]   J. Penaye, S. F. Toteu, A. Michard, J. M. Bertrand and D. Dautel, “Reliques Granulitiques d’Age Protérozo?que Inférieur dans la Zone Mobile Panafricaine d’Afrique Centrale au Cameroun: Géochronologie U-Pb sur Zircons,” Comptes Rendus de l’Académie des Sciences de Paris, Vol. 309, No. 2A, 1989, pp. 315-318.

[17]   J. P. Nzenti, “Prograde and Retrograde Garnet Zoning at High Pressure and Temperature in Metapelitic and Gre- natite Rocks from Yaoundé,” Journal of African Earth Sciences, Vol. 15, No. 1, 1992, pp. 73-79.doi:10.1016/0899-5362(92)90008-Z

[18]   J. P. Nzenti, P. Barbey and F. M. Tchoua, “Evolution Crustale au Cameroun: Eléments pour un Modèle Géodynamique de l’Orogenèse Néoprotérozo?que,” In: J.-P. Vicat and P. Bilong, Eds., Géologie et Environments au Cameroun, GEOCAM, Vol. 2, 1999, pp. 397-407.

[19]   E. L. T. Njiosseu, J. P. Nzenti, T. Njanko, B. Kapajika and A. Nédelec, “New U-Pb Zircon Ages from Tonga (Cameroon): Coexisting Eburnean-Transamazonian (2.1 Ga) and Pan-African (0.6 Ga) Imprints,”Comptes Rendus Géosciences, Vol. 337, No. 16, 2005, pp. 551-562. doi:10.1016/j.crte.2005.02.005

[20]   A. A. Ganwa, W. Frisch, W. Siebel, G. E. Ekodeck, C. K. Shang and V. Ngako, “Archean Inheritances in the Pyroxene-Amphibole-Bearing Gneiss of the Méiganga Area (Central North Cameroon): Geochemical and Pb/Pb Age Imprints,” Comptes Rendus Geosciences, Vol. 340, No. 4, 2008, pp. 211-222.doi:10.1016/j.crte.2007.12.009

[21]   M. L. Djouka-Fonkwe, B. Schulz, J. P. Tchouankoué and C. Nzolang, “Geochemistry of the Bafoussam Pan-Afri- can I- and S-type Granitoids in Western Cameroon,” Journal of African Earth Sciences, Vol. 50, No. 2-3, 2008, pp. 148-167. doi:10.1016/j.jafrearsci.2007.09.015

[22]   G. D. K. Nono, J. P. Nzenti, C. E. Suh and S. Ganno, “Geochemistry of Ferriferous, High-K Calc-Alkaline Gra- nitoids from Banefo-Mvoutsaha Massif (NE Bafous- sam), Central Domain of the Pan-African Fold Belt, Cameroon,” The Open Geology Journal, Vol. 4, No. 1, 2010, pp. 21-34.

[23]   A. N. Nchare, J. P. Nzenti, E. L. T. Njiosseu, S. Ganno and T. Ngnotué, “Synkinematic Ferro-Potassic Magmatism from the Mekwene-Njimafofire Foumban Massif, along the Foumban- Banyo Shear Zone in Central Domain of Cameroon Pan-African Fold Belt,” Journal of Geology and Mining Research, Vol. 2, No. 6, 2010. pp. 142-158.

[24]   C. Chebeu, C. D. N. Nlend, J. P. Nzenti and S. Ganno, “Neoproterozoic High-K Calc-Alkaline Granitoids from Bapa-Batié, North Equatorial Fold Belt, Central Cameroon: Petrogenesis and Geodynamic Significance,” The Open Geology Journal, Vol. 5, 2011, pp. 1-20.doi:10.2174/1874262901105010001

[25]   D. Soba, A. Michard, S. F. Toteu, D. I. Norman, J. Penaye, V. Ngako, J. P. Nzenti and D. Dautel, “Données Géochronologiques Nouvelles (Rb-Sr, U-Pb et Sm-Nd) sur la Zone Mobile Panafricaine de l’Est-Cameroun: Age Protérozoique Supérieur de la Série de Lom,”Comptes Rendus de l’Académie des Sciences de Paris, Vol. 312, No. 2, 1991, pp. 1453-1458.

[26]   G. Njiekak, W. D?rr, J. P. Tchouankoue and G. Zulauf, “U-Pb Zircon and Microfabric Data of (Meta) Granitoids of Western Cameroon: Constraints on the Timing of Pluton Emplacement and Deformation in the Pan-African Belt of Central Africa,” Lithos, Vol. 102, No. 3-4, 2008, pp. 460-477. doi:10.1016/j.lithos.2007.07.020

[27]   K. Govindaraju and R. Montanary, “Routine Performance of a Matrix-Correction Free X-Ray Flurorescence Spec- trometric Method for Rock Analysis,” X-ray Spectrome- try, Vol. 7, No. 3, 1978, pp. 148-151.doi:10.1002/xrs.1300070307

[28]   K. Govindaraju, “Report (1980) on Three GIT-IWG Rock Reference Samples: Anorthosite from Greenland, AN-G; Basalte d’Essey-la-Cote, BE-N; Granite de Beauvoir, MA-N,” Geostandards Newsletters, Vol. 4, No. 1, 1980, pp. 49-138. doi:10.1111/j.1751-908X.1980.tb00274.x

[29]   B. M. Jahn, P. Vidal and G. R. Tilton, “Archean Mantle Heterogeneity: Evidence from Chemical and Isotopic Abundances in Archean Igneous Rocks,” Philosophical Transactions of the Royal Society, Vol. 297, 1980, pp. 353-364. doi:10.1098/rsta.1980.0221

[30]   B. Schulz, H. Br?tz, K. Bombach and E. Krenn, “In situ Th-Pb Dating of Monazite by 266 nm Laser Ablation and ICP-MS with a Single Collector, and Its Control by EMP Analysis-Z. Angew,” Geology, Vol. 35, No. 4, 2007, pp. 377-392.

[31]   E. Jarosewich and L. A. Boatner, “Rare-Earth Element Reference Samples for Electron Microprobe Analysis,” Geostandards Newsletter, Vol. 15, No. 2, 1991, pp. 397- 399. doi:10.1111/j.1751-908X.1991.tb00115.x

[32]   J. J. Donovan, J. M. Hanchar, P. M. Picolli, M. D. Schrier, L. A. Boatner and E. Jarosewich, “A Re-Examination of the Rare-Earth-Element Orthophosphate Standards in Use for Electron-Microprobe Analysis,” Canadian Minera- logist, Vol. 41, No. 1, 2003, pp. 221-232.doi:10.2113/gscanmin.41.1.221

[33]   F. Finger and H. M. Helmy, “Composition and Total-Pb Model Ages of Monazite High Grade Paragneisses in the Abu Swayel Area, southern Eastern Desert, Egypt,” Mineralogy and Petrology, Vol. 62, No. 3-4, 1998, pp. 269- 289. doi:10.1007/BF01178032

[34]   J. M. Montel, S. Foret, M. Veschambre, C. Nicollet and A. Provost, “A Fast, Reliable, Inexpensive in-Situ Dating Technique: Electron Microprobe Ages of Monazite,” Chemical Geology, Vol. 131, No. 1, 1996, pp. 37-53. doi:10.1016/0009-2541(96)00024-1

[35]   M. J. Jercinovic and M. L., Williams, “Analytical Perils (and Progress) in Electron Microprobe Trace Element Analysis Applied to Geochronology: Background Acqui- sition, Interferences, and Beam Irradiation Effects,” American Mineralogist, Vol. 90, No. 5, 2005, pp. 526- 546. doi:10.2138/am.2005.1422

[36]   B. Buhn, M. M. Pimentel, M. Matteini and E. L. Dantas, “High Spatial Resolution Analysis of Pb and U Isotopes for Geochronology by Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC- ICP-MS),” Anais da Academia Brasiliera de Ciências, Vol. 81, No. 1, 2009, pp. 1-16.doi:10.1590/S0001-37652009000100011

[37]   S. E. Jackson, N. J. Pearson and W. L. Griffin, “The Ap- plication of Laser Ablation-Inductively Coupled Plasma- Mass Spectrometry to in situ U-Pb Zircon Geochronology,” Chemical Geology, Vol. 211, No. 1-2, 2004, pp. 47-69. doi:10.1016/j.chemgeo.2004.06.017

[38]   F. Albarède, P. Telouk, J. Blichert-Toft, M. Boyet, A. Agranier and B. Nelson, “Precise and Accurate Isotopic Measurements Using Multiple Collector ICPMS,” Geo- chimical and Cosmochimical Acta, Vol. 68, No. 12, 2004, pp. 2725-2744. doi:10.1016/j.gca.2003.11.024

[39]   L. P. Black, S. L. Kamo, C. M. Allen, D. W. Davis, J. N. Aleinikoff, J. W. Valley, R. Mundil, I. H. Campbell, R. J. Korsch, I. S. William and C. Foudoulis, “Improved 206Pb/238U Microprobe Geochronology by the Monitoring of a Trace-Element-Related Matrix Effect: SHRIMP, ID-TIMS, LA-ICP-MS and Oxygen Isotope Documen- tation for a Series of Zircon Standards,” Chemical Geology, Vol. 205, No. 1-2, 2004, pp. 115-140.doi:10.1016/j.chemgeo.2004.01.003

[40]   J. S. Stacey and J. D. Kramers, “Approximation of Ter- restrial Lead Isotope Evolution by a Two-Stage Mode,” Earth Planetary Science Letters, Vol. 26, No. 2, 1975, pp. 207-221. doi:10.1016/0012-821X(75)90088-6

[41]   K. R. Ludwig, “Users Manual for Isoplot/Ex rev. 2.49. A Geochronological Toolkit for Microsoft Excel,” Berkeley Geochronology Center Special Publication, Vol. 1a, 2001, pp. 1-55.

[42]   K. R. Ludwig, “User’s Manual for Isoplot/Ex v. 3.00. A Geochronological Toolkit for Microsoft Excel,” BGC Special Publication, Vol. 4, No. 1, 2003, pp. 1-71.

[43]   E. A. K. Middlemost, “Magmas and Magmatic Rocks,” Longman, London, 1985.

[44]   J. M. Bertrand, C. Dupuy, J. Dostal and I. Davidson, “Geochemistry and Geotectonic Interpretation of Grani- toids from Central Iforas (Mali, West Africa),” Precam- brian Research, Vol. 26, No. 3-4, 1984, pp. 265-283. doi:10.1016/0301-9268(84)90004-4

[45]   R. Ayuso and J. G. Arth, “The Northeast Kingdom Batho- liths, Vermon: Magmatic evolution and Geochemical Con- straints on the Origin of Acadian Granitics Rocks,” Con- tribution to Mineralogy and Petrology, Vol. 111, No. 1, 1992, pp. 1-23. doi:10.1007/BF00296574

[46]   K. Suzuki, M. Adachi and I. Kajisuka, “Electron Mic- roprobe Observations of Pb Diffusion in Metamorphosed Detrital Monazites,” Earth and Planetary Sciences Let- ters, Vol. 128, No. 3-4, 1994, pp. 391-405. doi:10.1016/0012-821X(94)90158-9

[47]   M. P. Searle, R. R. Parrish, K. V. Hodges, A. Hurford, M. W. Ayres and M. J., Whitehouse, “Shisha Pangma Leucogranite, South Tibetan Himalayan: Field Relations, Geochemistry, Age, Origin and Emplacement,” Journal of Geology, Vol. 105, No. 3, 1997, pp. 295-317.doi:10.1086/515924

[48]   B. Barbarin, “A Review of the Relationships between Granitoids Types, Their Origin and Their Geodynamics Environments,” Lithos, Vol. 46, No. 4, 1999, pp. 605- 626. doi:10.1016/S0024-4937(98)00085-1

[49]   P. I. Nabalek and M. Liu, “Petrology and Thermal Con- straints on the Origin of Leucogranites in Collisional Orogens,” Transactions of the Royal Society of Edin- burgh, Earth Sciences, Vol. 95, No. 1, 2004, pp. 73-85. doi:10.1017/S0263593304000094

[50]   C. F. Miller, “Are Strongly Peraluminous Magmas De- rived from Pelitic Sedimentary Sources?” Journal of Geology, Vol. 93, No. 6, 1985, pp. 673-689.doi:10.1086/628995

[51]   A. E. P. Douce, “Experimental Generation of Hybrid Si- licic Melts by Reaction of High Al Basalt with Meta- morphic Rocks,” Journal of Geophysical Research, Vol. 100, No. B8, 1995, pp. 623-639.

[52]   P. Le Fort, M. Cuney, C. Deniel, C. France-Lanord, S. M. F. Sheppard, B. N. Upreti and P. Vidal, “Crustal Genera- tion of the Himalayan Leucogranites,” Tectonophysics, Vol. 134, No. 1, 1987, pp. 39-57.doi:10.1016/0040-1951(87)90248-4

[53]   A. J. R. White and B. W. Chappell, “A-Type Granites: Geochemical Characteristics, Discrimination and Petro- genesis,” Contribution to Mineralogy and Petrology, Vol. 95, No. 4, 1987, pp. 407-419. doi:10.1007/BF00402202

[54]   N. B. W. Harris and S. Inger, “Trace Element Modelling of Pelitte-Derived Granites,” Contributions to Mineralogy and Petrology, Vol. 110, No. 1, 1992, pp. 46-56.doi:10.1007/BF00310881

[55]   B. J. Williamson, H. Downes, M. F. Thirlwall and A. Beard, “Geochemical Constraints on Restite Composition and Unmixing in the Velay Anatectic Granite, French Massif Central,” Lithos, Vol. 40, No. 2-4, 1997, pp. 295- 319. doi:10.1016/S0024-4937(97)00033-9

[56]   M. Cuney, P. Sabaté, P. Vidal, M. Marinho and H. Com- cei?ao, “The 2 Ga Peraluminous Magmatism of Jaco- bina-Contendas Mirante Belt (Bahia-Brasil): Major- and Trace-Element Geochemistry and Metallogenic Poten- tial,” Journal of Volcanology and Geothermal Research, Vol. 44, No. 1-2, 1990, pp. 123-141.doi:10.1016/0377-0273(90)90015-8

[57]   D. Vielzeuf and J. Hollaway, “Experimental Determina- tion of the Fluid-Absent Melting Relations in the Pelitic System,” Contribution to Mineralogy and Petrology, Vol. 98, No. 3, 1988, pp. 257-276. doi:10.1007/BF00375178

[58]   A. E. P. Douce and A. D. Johnston, “Phase Equilibria and Melt Productivity in the Politic System: Implications for the Origin of Peraluminous Granitoids and Aluminous Granulites,” Contribution to Mineralogy and Petrology, Vol. 107, No. 2, 1991, pp. 202-218. doi:10.1007/BF00310707

[59]   B. R. Frost, C. G. Barnes, W. J. Collins, R. J. Arculus, D. J. Ellis and C. D. Frost, “A Geochemical Classification for Granitic Rocks,” Journal of Petrology, Vol. 42, No. 11, 2001, pp. 2033-2048. doi:10.1093/petrology/42.11.2033

[60]   F. F. Altherr, A. Holl, E. Hegner, C. Langer and H. Kreuser, “High-Potassium, Calc-Alcaline I-Type Plutonism in the European Variscides: Nothern Vosges (France) and Northern Schwarzwald (Germany),” Lithos, Vol. 50, No. 1-3, 2000, pp. 51-73.doi:10.1016/S0024-4937(99)00052-3

[61]   C. Nzolang, H. Kagami, J. P. Nzenti and F. Holz, “Geochemistry and Preliminary Sr-Nd Isotopic Data on the Neoproterozoic Granitoids from the Bantoum Area, West Cameroon: Evidence for a Derivation from a Paleoproterozoic to Archean Crust,” Polar Geoscience, Vol. 16, 2003, pp. 196-226.

[62]   T. Njanko, A. Nedélec and P. Affaton, “Synkinematic High-K Calc-Alkaline Plutons Associated to the Pan-Af- rican Central Cameroon Shear Zone (West-Tibati area): Petrology and Geodynamic Significance,” Journal of African Earth Sciences, Vol. 44, No. 4-5, 2006, pp. 494- 510. doi:10.1016/j.jafrearsci.2005.11.016

[63]   J. P. Nzenti, B. Kapajika, G. W?rner and R. T. Lubala, “Synkinematic Emplacement of Granitoids in a Pan-Af- rican Shear Zone in Central Cameroon,” Journal of Afri- can Earth Sciences, Vol. 45, No. 1, 2006, pp. 74-86.doi:10.1016/j.jafrearsci.2006.01.005

[64]   J. P. Nzenti, P. Barbey, J. M. Bertrand and J. Macaudière, “La Cha?ne Panafricaine au Cameroun: Cherchons Suture et Modèle!” 15th Réunion des Sciences de la Terre, Nancy, 26-28 April 1994.

[65]   A. A. Ganwa, W. Frisch, W. Siebel, G. E. Ekodeck, C. K. Shang, J. M. Ondoa, M. Satir and J. T. Numbem, “Zircon Pb/Pb Evaporation Ages of Panafrican Metasedimentary Rocks in the Kombé-II Area (Bafia Group, Cameroon): Constraints on Protolith Age and Provenance,” Journal of African Earth Sciences, Vol. 51, No. 2, 2008, pp. 77-88.doi:10.1016/j.jafrearsci.2007.12.003

[66]   A. A. Ganwa, W. Siebel, C. K. Shang, N. Seguem and G. E. Ekodeck, “New Constraints from Pb-Evaporation Zircon Ages of the Méiganga Amphibole-Biotite Gneiss, Central Cameroon, on Proterozoic Crustal Evolution,” International Journal of Geosciences, Vol. 2, No. 2, 2011, pp. 138-147.

[67]   J. P. Nzenti, “Neoproterozoic Alkaline Meta-Ignous Rocks from the Pan-African North Equatorial Fold Belt (Yaoundé, Cameroon): Biotitites and Magnetite Rich Pyroxenites,” Journal of African Earth Sciences, Vol. 26, No. 1, 1998, pp. 37-47. doi:10.1016/S0899-5362(97)00135-8