Petrology of lherzolite xenoliths of HosséréSédévolcano(Adamawa plateau,Ngaoundéréarea,Cameroon)  

作　　者：O.F.Nkouandou J.M.Bardintzeff Fagny Mefire Njankouo Ndassa A.A.Sahabo H.Adama 

机构地区：[1]Department of Earth Sciences,Faculty of Sciences,University of Ngaoundere,P.O.Box.454,Ngaoundere,Cameroon [2]Univ Paris-Saclay,Sciences de la Terre,Volcanologie-Planetologie,UMR CNRS 8148 GEOPS,Bat.504,91405 Orsay,France [3]Laboratoire de volcanologie,Institut de Recherches Geologique et Minie`re,B.P.370,Buea,Cameroon

出　　处：《Acta Geochimica》2023年第5期817-831,共15页地球化学学报（英文）

基　　金：“Agence Universitaire de la Francophonie(AUF)”.

摘　　要：Numerous mantle xenoliths 6–12 cm in size and sub-angular to rounded in shape occur within Mio-Pliocene basanite lavas of the monogenic volcano of HosséréSédé in the Adamawa plateau.Xenoliths of spinel lherzolite exhibit protogranular,equigranular or porphyroclastic texture.Microprobe chemical analyses show that olivine is highly magnesian(Fo_(88-90)),clinopyroxene crystals are diopside and augite(Wo_(41.6–49.6)En_(45.3–53.7)Fs_(4.2–6.2)),orthopyroxene crystals are enstatite(Wo 1.4–1.5 En_(88.6–89.0)Fs_(9.6–9.9))and spinel crystals are mainly Al-spinel associ-ated to minor Cr-spinel.Estimated temperatures and pressures through empirical formulas show that HosséréSédé noliths have equilibrated between 1085 and 1204℃and 1.08 to 1.57 GPa,corresponding to sampling depths of 36 and 52 km.Detailed petrographical and mineral chemistry of HosséréSédénoliths evidences the com-plex nature and composition of the subcontinental lithosphere under the Adamawa plateau.This may involve a probable uplift of the whole area after a limited exten-sional event,possible metasomatism through melt infiltration during shearing of the lithospheric mantle along the Pan African strike-slip fault system.

关 键 词：Cameroon Adamawa HosséréSédé Subcontinental lithosphere XENOLITH PERIDOTITE LHERZOLITE 

分 类 号：P588.12[天文地球—岩石学]