A Gondwana pre-break up related magmatism in Bafoussam area, west Cameroon: source characteristics and 40Ar/39Ar geochronology

  • Authors

    • Gus Djibril Kouankap Nono The University of Bamenda
    • Pierre Wotchoko The University of Bamenda
    • Evine Laure Tanko Njiosseu Université de Dschang
    • Sylvestre Ganno Université de Yaoundé 1
    • Joelle Flore Tene Djoukam Université de Yaoundé 1
    • Yannick Seplong Université de Yaoundé 1
    • David Guimolaire Nkouathio Université de Dschang
    2019-05-05
    https://doi.org/10.14419/ijag.v7i1.21354
  • 40Ar-39Ar Dating, Dolerites, Gondwana Break-Up, Primitive Mantle.

  • The Gondwana pre-break up related formations in Bafoussam area are transitional calc-alkaline doleritic dykes exhibiting high Alumina and low Ti-Mg contents. Their REE compositions are similar to those of E-MORB (Nd/Nb≈1, Zr/Nb≤20). A high partial melting of about 20% of Garnet peridotites source having primitive mantle composition, is inferred to the studied rocks. They are slightly evolved 50<Mg#<54, and its clinopyroxenes are augite of high temperature (600°C-1100°C). The studied dykes were emplaced in a within-plate tectonic setting and yield a 40Ar-39Ar plateau ages of 229±7Ma. These ages are slightly different from those of dolerites from the Oban-Obudu massif (Nigeria), from the basaltic dyke of the Cameroon Volcanic Line and from the Karoo-Ferrar mafic magmatism, all interpreted as magmatism that preceded the break-up of Gondwana. The emplacement age of 229±7Ma of dolerites from Bafoussam area relates them to the very early stage of Gondwana pre-break up magmatism in central Africa.

     

     

     

     


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    Djibril Kouankap Nono, G., Wotchoko, P., Laure Tanko Njiosseu, E., Ganno, S., Flore Tene Djoukam, J., Seplong, Y., & Guimolaire Nkouathio, D. (2019). A Gondwana pre-break up related magmatism in Bafoussam area, west Cameroon: source characteristics and 40Ar/39Ar geochronology. International Journal of Advanced Geosciences, 7(1), 23-30. https://doi.org/10.14419/ijag.v7i1.21354