Research Article

Petrogenesis of Magnesian High-K Granitoids From Bitkine (Centrechad Massif): Major and Trace Elements Constraints

Mbaihoudou Diontar
Université Polytechnique de Mongo, Cameroon
Jean Claude Doumnang
Université de N’Djamena, Cameroon
Maurice Kwékam
Université de Dschang, Cameroon
* Corresponding author
Zagalo Al-hadj Hamid
Université de Dschang, Cameroon
Armand Kagou Dongmo
Université de Dschang, Cameroon
Julios Efon Awoum
Université de Dschang, Cameroon
Jules Tcheumenak Kouémo
University of Douala, Cameroon
DOI icon 10.24018/ejgeo.2020.1.5.78

Read Counter
454

Downloads
437

Citations

Share

Article Sidebar

Submitted 2020-10-09
Published 2020-10-09

Read counter = 454 times

Table of Contents

Article Main Content

Major and trace element data were used to constrain the nature and origin of the Bitkine gabbro-diorite magma.The gabbro-diorites of Bitkine within the Guéra Massif, and associated microgranular enclaves consist of plagioclase, k-feldspar, clinopyroxene, amphibole, biotite and quartz. Gabbro-diorites and enclaves are basic to intermediate rocks. They are high-K magnesian calc-alkaline with shoshonite affinity. ΣREE range from 132 to 436 ppm in gabbro-diorites, while they are from 134 to 207 ppm in enclaves. LREE are weakly enriched compared to HREE (La/Yb)N = (12.23 -41.40) and (6.20-31.86) respectively in gabbro-diorites and enclaves. These rocks show a weak negative anomaly in europium (Eu/Eu* = 0.78-1.07). They are rich in Ba and Sr, and show negative anomalies in Nb, Ta and Ti. The Nb/Ta, Rb/Cs and Ba/Nb ratios of the Bitkine gabbro-diorites and their enclaves indicate that they are derived from mantle magma modified by subducted fluids. This magma during its evolution by fractional crystallization was contaminated by crustal materials.

Keywords: Bitkine, Gabbro-diorite, High-k magnesian, Enriched mantle, Fractional crystallization

References

  1. M., Abdelsalam, J.P., Liégeois, R.J., Stern. The Saharan Metacraton. Journal of African Earth Sciences, vol. 34, pp.119–136. 2002.
     Google Scholar
  2. J.P., Liégeois, M.G., Abdelsalam, N., Ennih, A., Ouabadi. Metacraton: nature, genesis and behavior. Gondwana Research 23, pp.220-237. 2013.
     Google Scholar
  3. J.L., Schneider, J.P., Wol. Carte géologique et cartes hydrogéologiques à 1/1500000 de la République du Tchad. Mémoire explicatif. 2vol. Documents du BRGM. 209p. Orléans (France). 1992.
     Google Scholar
  4. I., Kusnir, H.A., Moutaye. Ressources minérales du Tchad : une revue. Journal of African Earth Sciences, vol. 24, pp.549-562.1997.
     Google Scholar
  5. M.Y., Kasser. Evolution précambrienne de la région du Mayo- Kebbi (Tchad). Un segment de la chaîne panafricaine. Thèse Muséum National d’Histoire Naturelle de Paris, 217p.1995.
     Google Scholar
  6. M., Isseini, A., Hamit, M., Abderamane. The tectonic and geological framework of the Mongo area, a segment of the Pan-African Guera Massif in Central Chad: evidences from field observations and remote sensing. Rev. Sci. Tchad, vol.1, pp.4–12. 2013.
     Google Scholar
  7. J.G., Shellnutt, N.H.T., Pham, W.D., Steven, M.W., Yeh, T.Y., Lee. Timing of collisional and post-collisional Pan-African Orogeny silicic magmatism in south-central Chad. Precambrian Research, vol. 301, pp.113-123. 2017.
     Google Scholar
  8. P., Louis. Contribution géophysique à la connaissance géologique du bassin du lac Tchad. Bulletin ORSTOM, 42p.
     Google Scholar
  9. N.H.T., Pham, J.G., Shellnutt, M.W., Yeh, T.Y., Lee, T.-Y. A-type granites from the Guéra Massif, Central Chad: Petrology, geochemistry, geochronology, and petrogenesis. EGU General Assembly Conference Abstracts 19, 6211. 2017.
     Google Scholar
  10. J.P., Liégeois, R., Black, J., Navez, L., Latouche. Early and late Pan-African orogenies in the Aïr assembly of terranes (Tuareg shield, Niger). Precambrian Research, vol. 68, pp.335-344. 1994.
     Google Scholar
  11. I.B., Suayah, J.S., Miller, B.V., Miller, T.M., Bayer, J.W., Rogers. Tectonic significance of Late Neoproterozoic granites from the Tibesti massif in southern Libya inferred from Sr and Nd isotopes and U-Pb zircon data. Journal of African Earth Science, vol. 44, pp.561–570.2006.
     Google Scholar
  12. R., Tchameni, A., Pouclet, J., Penaye, A.A., Ganwa, S.F., Toteu. Petrography and geochemistry of the Ngaoundéré Pan-African granitoids in Central North Cameroon: implications for their sources and geological setting. Journal of African Earth Science, vol. 44, pp.511-529. 2006.
     Google Scholar
  13. N., Fezaa, J.P., Liégeois, N., Abdallah, E.H., Cherfouh, B., De Waele, O., Bruguier, A., Ouabadi. Late Ediacaran geological evolution (575-555 Ma) of the Djanet terrane, eastern Hoggar, Algeria, evidence for a Murzukian intracontinental episode. Precambrian Research, vol. 180, pp.299-327. 2010.
     Google Scholar
  14. N.H.T., Pham, J.G., Shellnutt, M.W., Yeh, T.Y., Lee, T.-Y. Ediacaran juvenile continental crust formation within the Saharan Metacraton: evidence from the Guéra Massif, southern Chad. Geol. Soc. Taiwan Annu Meeting May 10th to 11th. 2017.
     Google Scholar
  15. N.H.T., Pham, J.G., Shellnutt, M.W., Yeh, Y., Iizuka. An Assessment of the Magmatic Conditions of Late Neoproterozoic Collisional and Post-collisional Granites Fromthe Guéra Massif, South-CentralChad. Front. Earth Sci. 8:318.doi: 10.3389/feart.2020.00318.2020.
     Google Scholar
  16. E., Ferré, G., Gleizes, R., Caby. Obliquely convergent tectonics and granite emplacement in the Trans-Saharan belt of Eastern Nigeria: a synthesis. Precambrian Research, vol.114, pp.199–219. 2002.
     Google Scholar
  17. S.F., Toteu, J., Penaye, Y.H.P., Djomani. Geodynamic evolution of the Pan-African belt in central Africa with special reference to Cameroon. Canadian Journal of Earth Science, vol. 41, pp.73–85. 2004.
     Google Scholar
  18. A., Peccerillo, S.R., Taylor. Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, Northern Turkey. Contribution to Mineralogy and Petrology, vol. 58, pp.63-81. 1976.
     Google Scholar
  19. P.C., Rickwood. Boundary lines within petrologic diagrams which use oxides of major and minor elements. Lithos, vol. 22, pp.247–264. 1989.
     Google Scholar
  20. M.P., Roberts, J.D., Clemens. Origin of high-potassium, calc-alkaline, I-type granitoids. Geology, vol. 21, pp.825-828. 1993.
     Google Scholar
  21. B.R., Frost, C.G., Barnes, W.J., Collins, R.J., Arculus, D.J., Ellis, C.D., Frost. A geochemical classification for granitic rocks. Journal of Petrology, vol. 42, pp.2033–2048. 2001.
     Google Scholar
  22. W.F. McDonough, S.S., Sun, A.E., Ringwood, E., Jagoutz, A.W., Hofmann. Potassium, rubidium, and cesium in the Earth and Moon and the evolution of the mantle of the Earth. Geochimica et Cosmochimica Acta, vol. 56, pp.1001-1012. 1992.
     Google Scholar
  23. W., Hofmann, K.P., Jochum, M., Seufert, W.M., White. Nb and Pb in oceanic basalts: new constraints on mantle evolution. Earth Planetary Science Letter, vol.79, pp.33-45. 1986.
     Google Scholar
  24. [24] B., Barbarin. A review of the relationships between granitoid types, their origins and their geodynamic environments. Lithos, vol.46, pp.605–626, 1999.
     Google Scholar
  25. J., Tarney, C.E., Jones. Trace element geochemistry of orogenic igneous rocks and crustal growth models. Journal of the Geological Society of London, vol. 151, pp.855-868. 1994.
     Google Scholar
  26. M.J., Defant, M.S., Drummond. Derivation of some modern arc magmas by melting of young subducted lithosphere. Nature, vol. 347, pp.662–665. 1990.
     Google Scholar
  27. M.P., Gorton, E.S., Schandl. From continents to island arcs: a geochemical index of tectonic setting for arc-related and within-plate felsic o intermediate volcanic rocks. Can. Mineral, vol. 38, pp.1065–1073. 2000.
     Google Scholar
  28. D., Müller, D.I, Groves. Potassic Igneous Rocks and Associated Gold–Copper Mineralization. 3rd edition. Springer-Verlag, Berlin (238 pp). 1997.
     Google Scholar
  29. K.C., Condie. Geochemical changes in basalts and andesites across the Archean Proterozoic boundary: identification and significance. Lithos vol.23, pp.1–18.1989.
     Google Scholar
  30. [30] S.S., Sun, W.F., McDonough. Chemical and isotopic systematic of oceanic basalts: implications for mantle composition and processes. Geological Society Special Publication, vol. 42, pp.313-345. 1989.
     Google Scholar
  31. C.R., Stern, R., Kilian. Role of the subducted slab, mantle wedge and continental crust in the generation of adakites from the Austral Volcanic Zone. Contribution to Mineralogy and Petrology, vol. 123, pp.263–281. 1996.
     Google Scholar
  32. N.L., Green. Influence of slab thermal structure on basalt source regions and melting conditions: REE and HFSE constraints from the Garibaldi volcanic belt, northern Cascadia subduction system. Lithos vol. 87, pp.23-49. 2006.
     Google Scholar
  33. [33] E., Bourdon, J.P., Eissen, M., Monzier, C., Robin, H., Martin, J., Cotton, M., Hall. Adakite-like lavas from Antisana Volcano (Ecuador): evidence for slab melt metasomatism beneath the Andean North Volcanic Zone. Journal of Petrology, Vol. 43, pp.199–217. 2002.
     Google Scholar
  34. J., Ahmadian, F., Sarjoughian, D., Lentz, A., Esna-Ashari, M., Murata, H., Ozawa. Eocene K-rich adakitic rocks in the Central Iran: Implications for evaluating its Cu–Au–Mo metallogenic potential. Ore Geology Reviews, vol. 72, pp.323-342. 2016.
     Google Scholar
  35. M., Kwékam, P., Affaton, O., Bruguier, J.P., Liégeois, G., Hartmann, E., Njonfang. The pan-African kekem gabbro-norite (West-Cameroon), U-Pb zircon age, geochemistry and Sr-Nd isotopes: Geodynamical implication for the evolution of the Central African fold belt. Journal of African Earth Sciences, vol. 84, pp.70-88, 2013.
     Google Scholar


Most read articles by the same author(s)