Geology, mineralogy and geochemistry of the Kekem dyke swarm (Western Cameroon): Insights into Paleozoic–Mesozoic magmatism and geodynamic implications - 07/09/17
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Abstract |
The broadly N70°–90°E-trending dykes swarm at Kekem cut across the Paleoproterozoic-to-Achean terranes of West Cameroon remobilized during the Pan-African orogeny. They are picrite basalts and basalts with tholeiitic/transitional affinity, as shown by mineralogical and geochemical data, with variable major and trace element contents, MgO ranges from 7.3 to 12.4wt.%, Cr from 190 to 411ppm, Ni from 15 to 234ppm. All the dykes are light REE enriched with LaN/YbN values of 5.3–8.1, suggesting a co-magmatic origin. They originated from a 2.8% partial melting of a spinel-mantle source with no or little crustal input. The geochemical features of Kekem dykes are similar to those of Paleozoic and Mesozoic dykes recorded in North and Central Africa, suggesting multiple reactivations of pre-existing fractures that resulted in the fragmentation of western Gondwana and the opening of Central and South Atlantic Oceans.
Le texte complet de cet article est disponible en PDF.Keywords : Dyke swarm, Tholeiitic/transitional basalts, Spinel mantle source, Rifting, Basement control, Western Gondwana
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Vol 349 - N° 4
P. 175-185 - juillet 2017 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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