Skip to Main Content
Book Chapter

Cameroon Line alkaline magmatism (central Africa): A reappraisal

By
Emmanuel Njonfang
Emmanuel Njonfang
Laboratoire de Géologie, Ecole Normale Supérieure, Université de Yaoundé I, B.P. 47, Yaoundé, Cameroon
Search for other works by this author on:
Alexandre Nono
Alexandre Nono
Département des Sciences de la Terre, Faculté des Sciences, Université de Dschang, B.P. 67, Dschang, Cameroon
Search for other works by this author on:
Pierre Kamgang
Pierre Kamgang
Département des Sciences de la Terre, Faculté des Sciences, Université de Yaoundé I, B.P. 812, Yaoundé, Cameroon
Search for other works by this author on:
Vincent Ngako
Vincent Ngako
Mega Uranium Corporation Cameroon PLC, P.O. Box 14055, Yaoundé, Cameroon
Search for other works by this author on:
Félix M. Tchoua
Félix M. Tchoua
Département des Sciences de la Terre, Faculté des Sciences, Université de Yaoundé I, B.P. 812, Yaoundé, Cameroon
Search for other works by this author on:
Published:
June 01, 2011

Alkaline magmatism along the Cameroon Line has been active for at least 67 m.y. and is currently defined by an almost SW-NE geological lineament (mean value: N30°E). Available petrological, geochemical, and structural data obtained over the last 20 yr lead us to reappraise its mechanism of emplacement. Known as the second most important geological curiosity in Africa, after the East African Rift system, it displays a continental part and an oceanic part, a unique feature in Africa and even in the world. The continental part contains both plutonic and volcanic massifs, and the oceanic part consists only of volcanic massifs. Plutonic rocks as a whole define a complete series of gabbro-diorite-monzonite-syenite-granite type, whereas volcanic rocks display abundant basic (basalt-hawaiite) and felsic (trachyte-phonolite-rhyolite) lavas with very few intermediate ones (mugearite-benmoreite). The formerly entire alkaline nature of these rocks is here ruled out by the discovery of volcanoes with geochemically transitional affinities in some areas of the continental sector. On the other hand, new K-Ar and 40Ar/39Ar dates confirm the absence of any age migration associated with the SW-NE linear trend. This lack of steady time-space migration and the SW-NE trend have also been observed in the magmatic provinces of Nigeria and Benue Trough, which share similar geochemical features with the Cameroon Line, and along the NE-SW major igneous lineaments in South Africa. The mechanism of such episodic emplacement of alkaline magmatism can be better explained in terms of complex interactions between hotspots and lithospheric fractures during African plate motion.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Special Papers

Volcanism and Evolution of the African Lithosphere

Luigi Beccaluva
Luigi Beccaluva
Dipartimento di Scienze della Terra, Università di Ferrara, Italy
Search for other works by this author on:
Gianluca Bianchini
Gianluca Bianchini
Dipartimento di Scienze della Terra, Università di Ferrara, Italy
Search for other works by this author on:
Marjorie Wilson
Marjorie Wilson
School of Earth & Environment, The University of Leeds, Leeds, UK
Search for other works by this author on:
Geological Society of America
Volume
478
ISBN print:
9780813724782
Publication date:
June 01, 2011

References

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal