Petrogenesis and geotectonic setting of the Pan-African basement rocks in Bamenda Massif, Obudu Plateau, southeastern Nigeria: Evidence from trace element geochemistry  

作　　者：UKAEGBU V.U EKWUEME B.N 

机构地区：[1]Department of Geology, University of Port Harcourt, Port Harcourt, Nigeria [2]Department of Geology, University of Calabar, Calabar, Nigeria

出　　处：《Chinese Journal Of Geochemistry》2006年第2期122-131,共10页中国地球化学学报

摘　　要：The rocks of the Obudu Plateau range from high-grade metagreywacke-pelite sequence to metaigneous (granitic to tholeiitic) and polymagmatic (calc-alkaline granitic to olivine tholeiitic) igneous rocks. Several co-variance diagrams and other parameters indicate that the trace elements of rocks in southern Obudu Plateau exhibit systematic variations and suggest highly heterogeneous protoliths. The tectonic setting of the rocks indicates rifting and collisional to non-orogenic emplacements in oceanic to ensialic environments. The calc-alkaline and tholeiitic nature of the magmatism as well as the greywacke-pelite sequence is suggestive of an Andean-type continental environment.The rocks of the Obudu Plateau range from high-grade metagreywacke-pelite sequence to metaigneous （granitic to tholeiitic） and polymagmatic （calc-alkaline granitic to olivine tholeiitic） igneous rocks. Several co-variance diagrams and other parameters indicate that the trace elements of rocks in southern Obudu Plateau exhibit systematic variations and suggest highly heterogeneous protoliths. The tectonic setting of the rocks indicates rifting and collisional to non-orogenic emplacements in oceanic to ensialic environments. The calc-alkaline and tholeiitic nature of the magmatism as well as the greywackepelite sequence is suggestive of an Andean-type continental environment.

关 键 词：微量元素 岩石成因论 地壳构造 花岗岩 橄榄石 

分 类 号：P54[天文地球—构造地质学]