 | | Journal (article/letter/editorial) | | Structural environmentof Zr in two inosilicatesfrom Cameroon: Mineralogical and geochemicalimplications Fru...l-2wto/oZrOr)from a phonolite of the Rumpi Hills volcanic complex, west Cameroon, were examined using X-ray absorption...the crystallization of the phonolites of the Rumpi Hills volcanic complex, in which Na- and Fe2*-rich...ratio during later stagesofdifferentiation ofthe Rumpi Hills peralkaline melt should favor the incompatible...New South Wales (Duggan, 1988), and the Rumpi Hills, Cameroon (Nkoumbou, 1990), and in alkaline igneousrocks |  | | Journal (article/letter/editorial) | | Clinopyroxene from some felsic alkaline rocks of the Cameroon Line, central Africa: petrological implications...rocks belonging to the continental part of the Cameroon Line (CL). The investigated samples include both...contamination on the observed trends. Key-words: Cameroon Line, alkaline complexes, felsic rocks, Zr- and...aegirines, clinopyroxene trends. 1. Introduction The Cameroon Line (CL) is a prominent geological feature in...represented by the volcanic massifs of Mount Cameroon, Rumpi, Manengouba, Bambouto, Oku and the volcanic |  | | Book | | ring complexes and the chapter devoted to the Cameroon line. A detailed review of African ring complexes... XIV 2 Contents Phanerozoic Volcanism of Southwest Uganda: A Case for Regional K and lile Enrichment...Ultrapotassic Mafic-Ultramafic Magmatism in the Southwest Uganda Region of the African Rift: Implications from...Mafic-Ultramafic Ultra potassic Rocks of the Southwest Ugandan Area ........................... 3 Inferences.... . . ... 3 The Crust Under the Canary Islands Region ............. 4 Network of Fractures and Identity |  | | Journal (article/letter/editorial) | | volcanism in the Upper Benue valley, northern Cameroon (Central Africa) Received: 16 June 2002 / Accepted:...mean) occur in the Upper Benue valley, northern Cameroon (Central Africa). The complete alkaline series...trachytic texture and contain xenocrysts of K-feldspar, apatite, quartz and unstable biotite. Phonolites...both the continental and oceanic sectors of the Cameroon Line. The Upper Benue valley basaltic magmas (87Sr/86Sr0...Garoua rift is the N120E–130E propagation in Cameroon of the Yola branch and is limited by strike-slip |  | | Book (volume) | | where is the mean cation radius (A) An unusual alkali amphibole which is di-octahedral, i.e. has appreciable...site is occupied largely by Mn. In the calcic and alkali amphiboles where M4 is occupied largely by Ca,...occupies the M4 site in holmquistite but in the alkali amphiboles it is a member of the C group cations...in richterite, katophorite and taramite. In the alkali amphiboles the glaucophane and eckermannite end...groups but play a lesser role in others, e.g. Na in alkali and Fe.Mg amphibole respectively. Special rules |
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