The Mesozoic to Early Cenozoic Magmatism of the Benue Trough (Nigeria); Geochemical Evidence for the Involvement of the St Helen
JOURNAL OF PETROLOGY VOLUME 37 NUMBER 6 PAGES 1341-1358 1996 C. COULON1*, P. VIDAL2, C. DUPUY3, P. BAUDIN1, M. POPOFF*, H. MALUSKI5 AND D. HERMITTE1 'PETROLOGIE MAGMATIQUE, URA 1277, CEREGE, BP 80, 15545 AIX EN PROVENCE CEDEX 4, FRANCE 'CENTRE DE RECHERCHES VOLCANOLOGIQUES, URA 10, 63038 CLERMONT FERRAND CEDEX, FRANCE 'CENTRE GEOLOGIO.UE ET GEOPHYSIO.UE, CNRS, PLACE BATAILLON, J4095 MONTPELLIER CEDEX, FRANCE *INSTITUT DE GEODYNAMIQ.UE, URA 1279, UNIVERSITE DE NICE—SOPHIA ANTIPOLIS, AVENUE EINSTEIN, 06560 VALBONNE, FRANCE JLABORATOIRE DE GEOCHRONOLOGIE—GEOCHIMIE, URA 176J, PLACE BATAILLON, 34095 MONTPELLIER CEDEX, FRANCE The Mesozoic to Early Cenozoic Downloaded from https://academic.oup.com/petrology/article/37/6/1341/1406521 by guest on 28 September 2021 Magmatism of the Benue Trough (Nigeria); Geochemical Evidence for the Involvement of the St Helena Plume The Benue Trough is a continental rift related to the opening of Equatorial Atlantic. Moreover, the geochemical similarity the equatorial domain of the South Atlantic which was initi- between the alkaline magmatism of the Benue Trough and that ated in Late Jurassic-Early Cretaceous times. Highly diversi- of the Cameroon Line suggests that both magmatic provinces fied and volumetrically restricted Mesozoic to Cenozoic were related to the St Helena plume. Finally, the temporal magmatic products are scattered throughout the rift. Three per- change of the mantle sources observed in the Benue Trough can iods of magmatic activity have been recognized on the basis of be accounted for by the recent models of plume dynamics, in the *°Ar-39Ar ages: 147-106 Ma, 97-81 Ma and 68-49 Ma.
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