New K–AR ages of tchabal mbabo alkaline volcano massif, Cameroon volcanic line and adamawa plateau (central Africa)

  • Abstract
  • Keywords
  • References
  • PDF
  • Abstract

    Tchabal Mbabo in Central Africa is a voluminous volcano massif composed of alkali lava series. K-Ar geochronology data obtained from three samples of basanite - trachyandesite composition defined at least two volcanic activities. The first at end Eocene (38.22 ± 0.80 Ma) and the second during Oligocene (28.88 ± 0.61 and 28.60 ± 0.60Ma). The distribution of different ages along the Cameroon Volcanic Line is difficult to council with any migration of magmatic activity, as previously suggested. The most realistic scenario for the formation of Cameroon Line is that the ascent of lavas has been favored by the crustal discontinuities inherited from the Pan-African orogeny and reactivated during Mesozoic and Cenozoic. ICP MS and ICP AES analyses show that basanite lavas are the result of 2 % melting of sub-lithospheric mantle source containing garnet and phlogopite phases; the trachyandesites are formed by fractional crystallization of K-feldspar, amphibole, clinopyroxene and Fe-Ti oxides.

  • Keywords

    K-Ar Age; Tchabal Mbabo Volcano; Cameroon Volcanic Line; Adamawa Plateau; Central Africa.

  • References

    1. [1] Aka FT, Nagao K, Kusakabe M, Sumino H, Tanyileke G, Bekoa A & Hell J (2004) Symmetrical Helium isotope distribution on the Cameroon Volcanic Line, West Africa. Chemical Geology 203, 205-223.

      [2] Aka FT, Nagao K, Kusakabe M &Nfomou N (2009).) Cosmogenic helium and neon in mantle xenoliths from the Cameroon Volcanic Line (West Africa): Preliminary observations. Journal of African Earth Sciences 55, 175-184.

      [3] Bellon H & Rangin C (1991) Geochemistry and isotopic dating of Cenozoic volcanic arc sequences around the Celebes and Sulu Seas. In Proceedings of the Ocean Drilling Program (Silver EA, Rangin C, Breymann MT ed.), Scientific Results 124, pp 321–338.

      [4] Carignan J, Hild P, Mévelle G, Morel J &Yeghicheyan D (2001) Routine analyses of trace elements in geological samples using flow injection and low pressure on-line liquid chromatography coupled to ICP-MS: a study of geochemical reference materials BR, DR-N, UB-N, AN-G and GH. Geostandards Newslett 25, 187-198.

      [5] Charbit S, Guillou H & Turpin L (1998) Cross calibration of K-Ar standard minerals using an unspikedAr measurement technique. Chemical Geology 150, 147–159.

      [6] Chauvel C, Hofmann AW & Vidal P (1992) HIMU—EM: The French Polynesian connection. Earth Planet Science Letters 110, 99-119.

      [7] Déruelle B, Moreau C, Nkoumbou C, Kambou R, Lissom J, Njonfang E, Ghogomu RT &Nono A (1991) The Cameroon Line: a review. In Magmatism in Extensional Structural Settings (Kampunzu AB &Lubala R eds.), Springer-Verlag, Berlin, 274-327.

      [8] Déruelle B, Ngounouno I &Demaiffe D (2007) The ‘Cameroon Hot Line’ (CHL): a unique example of active alkaline intraplate structure in both oceanic and continental lithospheres. ComptesRendus Geosciences 339, 589-600.

      [9] Déruelle B (1994) Le magmatisme de la ‘’Ligne du Cameroun’’: le bilanpositif des deuxdernièresdécennies de coopération Franco-Camerounaise. Pangea, 30-36.

      [10]Dorbath C, Dorbath L, Fairhead JD & Stuart GW (1986) ateleseismic delay time study across the Central African Shear Zone in the Adamawa region of Cameroon, West Africa. Geophys. J. R. Astr. Soc. 86, 751-766.

      [11]Dorbath L, Dorbath C, Stuart GW &Fairhead JD (1984) Structure de la croûte sous le plateau de l’Adamaoua (Cameroun). C. R. Acad. Sci. Paris 298, 539–542.

      [12]Dunlop HM (1983) Strontium isotope geochemistry and potassium-argon study on volcanic rocks from the Cameroon Line,West Africa. PhD Thesis, Univ. Edinburgh, UK.

      [13]Fagny AM, Nkouandou OF, Déruelle B & NGOUNOUNO I (2012) revised petrology and new chronological data on the peralkaline felsic lavas of Ngaoundéré volcanism (Adamawa Plateau, Cameroon, Central Africa): evidence of open-system magmatic processes. AnaleleStiintifice ale Universitatii “Al. I. Cuza” din Iasi SeriaGeologie 58, 5-22.

      [14]Fitton JG & Dunlop HM (1985) The Cameroon Line, West Africa and its bearing on the origin of oceanic and continental alkali basalt. Earth. Planet. Sci. Lett. 72, 23-38.

      [15]Fitton JG (1980) The Benue trough and Cameroon line-a migrating rift system in West Africa. Earth and Planetary Science Letters 51, 132-138.

      [16]Fitton JG (1987) The Cameroon line, West Africa: a comparison between oceanic and continental alkaline volcanism. In Alkaline Igneous Rocks (Fitton JG & Upton BCG eds). Geol. Soc., London, 273-291.

      [17]Fitton JG (1983) Active versus passive continental rifting: evidence from the West African rift system. Tectonophysics 94, 473-481.

      [18]Fuhrmann U, Lippolt H & Hess JC (1987) HD-B1 Biotite reference material for K-Ar chronometry. Chemical Geology 66, 41-51.

      [19]Ganwa AA, Frisch W, Siebel W, Ekodeck GE, Cosmas SK &Ngako V (2008) Archean inheritances in the pyroxene-amphibole bearing gneiss of the Méiganga area (Central North Cameroon): Geochemical and 207Pb/206Pb age imprints. C. R. Géosciences 340, 211–222.

      [20]Gouhier J, Nougier J &Nougier D (1974) Contribution à l’étudevolcanologique du Cameroun: Ligne du Cameroun-Adamaoua. Annales Fac. Sci., Cameroun 17, 3-49.

      [21]Hautmann S &Lippolt HJ (2000) Ar-40/Ar-39 dating of central European K-Mn oxides - a chronological framework of supergene alteration processes during the Neogene. Chemical Geology 170, 1-4, 37-80.

      [22]Hess JC &Lippolt HJ (1994) Compilation of K–Ar measurements on HD-B1 standard biotite. Odin, G.S. (Ed.), Phanerozoic Time scale. Bulletin Liaison Informations, I.U.G.S. Subcommission on Geochronology 12, 19-23.

      [23]Hofmann AW (1988) Chemical differentiation of the Earth: the relationship between mantle, continental crust, and oceanic crust. Earth and Planetary Science Letters 90, 297-314.

      [24]Kamdem JB, Kraml M, Keller J, Henjes-Kunst F (2002) Cameroon Line magmatism: conventional K/Ar and single-crystal laser 40Ar/39Ar ages of rocks and minerals from the HossereNigoanorogenic complex, Cameroon. Journal of African Earth Sciences 35, 1, 99-105.

      [25]Kamgang P, Njonfang E, Nono A, Dedzo MG &Tchoua FM (2010) Petrogenesis of a silicic magma system: Geochemical evidence from Bamenda Mountains, NW Cameroon, Cameroon Volcanic Line. Journal of African Earth Sciences 58, 285-304.

      [26]Kampunzu AB &Popoff M (1991) Distribution of the main Phanerozoic African rifts and associated magmatism: introductory notes. In Magmatism in Extensional Structural Settings, the Phanerozoic African Plate (Kampunzu AB &Lubala RT eds.), Springer-Verlag, Berlin, 2–10.

      [27]Le Maitre RW (2002) Igneous Rocks— A Classification and Glossary of Terms. Recommendations of the IUGS Sub-Commission on the Systematics of Igneous Rocks. 2nd edn, Cambridge University Press, Cambridge, pp 236.

      [28]Leake BE, Woolley AR, Arps CES, Birch WD, Gilbert MC, Grice JD, Hawthorne FC, Kato A, Kisch HJ, Krivovichev VG, Linthout K, Laird J, Mandarino JA, Maresch WV, Nickel EH, Rock NMS, Schumacher JC, Smith DC, Stephenson NCN, Ungaretti L, Whittaker EJW &Youzhi G (1997) Nomenclature of amphiboles: report of the subcommittee on amphiboles of the international mineralogical association, commission on new minerals and mineral names. The Canadian Mineralogist 35, 219-246.

      [29]Lee DC, Halliday AN, Fitton JG &Poli G (1994a). Isotopic variations with distance and time in the volcanic islands of the Cameroon line: evidence for a mantle plume origin. Earth lume origin. Earth Planet. Sci. Lett. 123, 119–138.

      [30]Lee DC, Halliday AN, Hall CM &Fitton JG (1994b) Similarities and differences between continental and oceanic basalts in the Cameroon Line (abstract). Eighth International Conference on Geochronology, Cosmochronology and Isotope Geology, Berkeley, pp 188.

      [31]Marzoli A, Renne PR, Piccirillo EM, Castorina F, Bellieni G, Melfi AJ, Nyobe JB &N'ni J (1999) silicic magmas from the continental Cameroon Volcanic Line (Oku, Bambouto and Ngaoundere):40Ar-39Ar dates, petrology, Sr-Nd-O isotopes and their petrogenetic significance. Contrib. Mineral. Petrol. 135, 133-150.

      [32]Mbowou GIB, Lagmet C, Nomade S, Ngounouno I, Déruelle B &Ohnenstetter D (2012) Petrology of the Late Cretaceous peralkaline rhyolites (pantellerite and comendite) from Lake Chad, Central Africa. Journal of Geosciences 57, 127–141.

      [33]Moreau C, Regnoult JM, Déruelle B &Robineau B (1987) A new tectonic model for the cameroun line, central Africa. Tectonophysics 139, 317-334.

      [34]Morgan WJ (1971) Convective plumes in the lower mantle. Nature 230, 42-43.

      [35]Morgan WJ (1972a).) Deep mantle convection plumes and plate motions. Bull. Am. Assoc. Pet. Geol. 56, 203-213.

      [36]Morgan WJ (1972b) Plate motions and deep mantle convection. Geol. Soc. Am. Mere. 132, 7-22.

      [37]Morimoto N, Fabriès J, Ferguson AK, Ginzburg IV, Ross M, Seifert FA, Zussman J, Aoki K &Gottardi G (1988) Nomenclature of pyroxenes. Mineral. Mag. 52, 535-550.

      [38]Ngounouno I, Déruelle B, Demaiffe D &Montigny R (2003) Petrology of the Cenozoic volcanism in the Upper Benue valley, northern Cameroon (Central Africa). Contrib. Mineral. Petrol. 145, 87–106.

      [39]Nkouandou OF, Ngounouno I &Deruelle B (2010) Géochimie des laves basaltiquesrécentes des zones Nord etEst de Ngaoundéré (Cameroun, Plateau de l’Adamaoua, Afriquecentrale): pétrogenèse et nature de la source. International Journal of Biological and Chemical Sciences 4, 984-1003.

      [40]Nkouandou OF, Ngounouno I, Déruelle B, Onhenstetter D, Montigny R &Demaiffe D (2008) Petrology of the Mio-Pliocene Volcanism to the North and East of Ngaoundéré (Adamawa-Cameroon). ComptesRendus Geoscience 340, 28-37.

      [41]Nono A, Déruelle B, Demaiffe D &Kambou R (1994) Tchabal Nganha volcano in Adamawa (Cameroon): petrology of a continental alkaline lava series. J. Volcanol. Geotherm. Res. 60, 147–178.

      [42]Pouchou JL &Pichoir F (1991) Quantitative analysis of homogeneous or stratified microvolumes applying the model “PAP”. In Electron Probe Quantification (Heinriche DE ed.). Plenum Press, New York, 31–75.

      [43]Scarrow JH & Cox KG (1995) Basalts generated by decompressive adiabatic melting of a mantle plume: a case study from the Isle of Skye, NW Scotland. Journal of Petrology 36, 3–22.

      [44]Tchameni R, Pouclet A, Penaye J, Ganwa AA &Toteu SF (2006) Petrography and geochemistry of the Ngaoundéré Pan-African granitoids in central North Cameroon: implications for their sources and geological setting. J. Afr. Earth Sci. 44, 511–529.

      [45]Temdjim R, Njilah IK, Kamgang P, Nkoumbou C (2004) Donnéesnouvellessur les laves felsiques de Ngaoundéré (Adamaoua, ligne du Cameroun): chronologie K-Ar et pétrologie. African Journal of Science and Technology Science and Engineering 5, 2, 113-123.

      [46]Wandji P, Tsafack JPF, Bardintzeff JM, Nkouathio DG, Kagou DA, Bellon H &Guillou H (2009) Xenoliths of dunites, wehrlites and clinopyroxenite in the basanites from Batoke volcanic cone (Mount Cameroon, Central Africa): petrogenetic implications. Mineralogy and Petrology 96, 81-98.

      [47]Wilson JT (1973) Mantle plumes and plate motions. Tectonophysics 19, 149-164.

      [48]Wilson WJ 1965. Evidence from ocean islands suggesting movement in the earth, Philos. Trans. R. Soc. London 258, 145-167.

      K-Ar Age; Tchabal Mbabo Volcano; Cameroon Volcanic Line; Adamawa Plateau; Central Africa.




Article ID: 6516
DOI: 10.14419/ijag.v4i2.6516

Copyright © 2012-2015 Science Publishing Corporation Inc. All rights reserved.