Petrological and Geochemical Studies on the Si-Undersaturated Rocks of the Mount Cameroon: Genesis of the Camptonite and Nephelinite at the Cameroon Hot Line

作     者：Ntoumbé Mama Amaya Adama Diguim Kepnamou Amadou Mbowou Gambie Isaac Bertrand Naimou Seguem Ngounouno Ismaïla Ntoumbé Mama;Amaya Adama;Diguim Kepnamou Amadou;Mbowou Gambie Isaac Bertrand;Naimou Seguem;Ngounouno Ismaïla

作者机构：Department of Mines Geology School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon Department of Geomatic and Geology Mapping School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon Department of Geology Faculty of Sciences and Techniques University Adam Barka of Abeche Abeche Chad 

出 版 物：《Open Journal of Geology》 (地质学期刊（英文）)

年 卷 期：2021年第11卷第6期

页      面：239-252页

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

主　　题：Nephelinite Camptonite Link Source Cameroon Hot Line 

摘      要：The Cameroon hot line is dominated by magmatic rocks. The variations of magma and chemistry are generally due to the difference of physical conditions and chemistry in the magma source region during the ascent of magma. The Mt Etinde and the Mt Cameroon, both edifices belong to the Cameroon Hot line, have a particularity some rare rocks such as camptonite and nephelinite. The relationship between the silica undersaturated rocks in the both edifices is characterized by the lateral variation appear through the petrography of the different rocks. The concerned geochemical data allow to compare the Mount Etinde nephelinite and Mount Cameroon camptonite where the differentiation process reflects geochemical affinities from a basaltic magma source on the Cameroon hot line. The compatible elements between the Mount Etinde nephelinite and the Mount Cameroon camptonite and basalt correlate with the difference in modal compositions of mineral phases. The lateral variation of major and trace element contents in the Mount Cameroon camptonite and Mount Etinde nephelinite seem to be related to the difference in the fractional crystallization processes of mineral phases, the difference in the partial melting processes and the metasomatism source rich in volatile. The silica-undersaturated character of the camptonite and nephelinite could be attributed to assimilation of carbonate rocks within depth-level magma chambers. Trace element AFC modelling revealed that the parental magmas of both edifice volcanic rocks were mostly affected by fractional crystallisation coupled with metasomatism process in Ca rich source.