Rhyolites of the Mbépit Massif in the Cameroon Volcanic Line: an early extrusive volcanic episode of Eocene age
| Autor: | Pierre Wandji, Hervé Bellon, Dieudonné Tchokona Seuwui, Bernard Platevoet, Jacques-Marie Bardintzeff |
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| Přispěvatelé: | Laboratoire de Géologie, Université de Yaoundé I, Département des Sciences de la Terre, Laboratoire de pétrographie-volcanologie, Université Paris-Sud - Paris 11 (UP11), Institut universitaire de formation des maîtres - Académie de Versailles (IUFM Versailles), Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine, Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), ENS Yaoundé |
| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: |
geography
geography.geographical_feature_category Felsic 010504 meteorology & atmospheric sciences Lava Geochemistry [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography Massif 010502 geochemistry & geophysics 01 natural sciences Peralkaline rock Porphyritic Geophysics Volcano Geochemistry and Petrology Rhyolite Phenocryst Geology 0105 earth and related environmental sciences [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy |
| Zdroj: | Mineralogy and Petrology Mineralogy and Petrology, Springer Verlag, 2008, 94 (3-4), pp.271-286. ⟨10.1007/s00710-008-0013-6⟩ |
| ISSN: | 0930-0708 1438-1168 |
| Popis: | International audience; The Mbépit Massif, one of the oldest volcanoes of the Cameroon Volcanic Line, was built up during the Eocene (40K/40Ar ages of 45.5 and 44.0 Ma). Located in the Eastern part of the Noun Plain, North-East of Foumbot, this massif is made up mainly of rhyolitic domes and thick, viscous lava flows. Such felsic lavas are rather rare in the Cameroon Volcanic Line. Most rhyolites are porphyritic and contain phenocrysts of K-feldspars (Or97–89), Na-feldspars (Ab99–88) and quartz. Scarce Fe–Ti oxides comprise titanohaematite and hemo-ilmenite. Owing to their low CaO contents, rhyolite compositions range from metaluminous to peraluminous (with normative corundum) and less commonly, peralkaline (normative aegirine). Chondrite-normalised REE patterns show LREE enrichment; and LaN/YbN ratios between 12.2 and 17.2, with prominent negative Eu anomalies (0.16 |
| Databáze: | OpenAIRE |
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