Geochemical Signatures of Séguéla Peridotites in the West African Craton  

作　　者：Allialy Marc Ephrem Dicko Kagou Houssou N’guessan Nestor Kouamelan Alain Nicaise Coulibaly Yacouba Allialy Marc Ephrem;Dicko Kagou;Houssou N’guessan Nestor;Kouamelan Alain Nicaise;Coulibaly Yacouba(Laboratory of Geology, Mineral and Energy Resources (LGRME), Faculty of Earth Science and Mineral Resources, Félix Houphoueët Boigny University, Abidjan, Côte d’Ivoire)

机构地区：[1]Laboratory of Geology, Mineral and Energy Resources (LGRME), Faculty of Earth Science and Mineral Resources, Félix Houphoueë t Boigny University, Abidjan, Cô te d’Ivoire

出　　处：《Journal of Geoscience and Environment Protection》2022年第12期100-116,共17页地球科学和环境保护期刊（英文）

摘　　要：The present study deals with peridotites found in the paleo-proterozoic domain of the Leo Man Shield, Séguéla region, west-central of Côte d’Ivoire. Results show that Séguéla peridotites are composed of lherzolites, dunites and harzburgites. However, iherzolites are the most abundant. The phenocrysts in these rocks are olivine most often serpentinised, and pyroxenes, represented by diopside and enstatite. Amphiboles are divided into two groups: magmatic amphiboles and those from the destabilization of clinopyroxene. Spinels have CrO₃ content which varies between 28% and 37%, Al₂O₃ between 33% - 41% and MgO is equal to 18%;they are poor in TiO₂ and do not contain zinc oxide. Séguéla peridotites are characterised by a negative anomaly in Nb-Ta, associated with an enrichment of lithophilic elements and light rare earth elements with a fractionation rate (La/Yb) which varies between 46.22 and 150.72 and heavy rare earth elements, and HFSE depletion, which may suggest that were formed in an art context, that is, a mantle enriched by fluids from a subduction zone. However, another hypothesis could be considered, that of the interaction between the mantle and magmas in a subduction zone context.The present study deals with peridotites found in the paleo-proterozoic domain of the Leo Man Shield, Séguéla region, west-central of Côte d’Ivoire. Results show that Séguéla peridotites are composed of lherzolites, dunites and harzburgites. However, iherzolites are the most abundant. The phenocrysts in these rocks are olivine most often serpentinised, and pyroxenes, represented by diopside and enstatite. Amphiboles are divided into two groups: magmatic amphiboles and those from the destabilization of clinopyroxene. Spinels have CrO₃ content which varies between 28% and 37%, Al₂O₃ between 33% - 41% and MgO is equal to 18%;they are poor in TiO₂ and do not contain zinc oxide. Séguéla peridotites are characterised by a negative anomaly in Nb-Ta, associated with an enrichment of lithophilic elements and light rare earth elements with a fractionation rate (La/Yb) which varies between 46.22 and 150.72 and heavy rare earth elements, and HFSE depletion, which may suggest that were formed in an art context, that is, a mantle enriched by fluids from a subduction zone. However, another hypothesis could be considered, that of the interaction between the mantle and magmas in a subduction zone context.

关 键 词：Geochemestry PERIDOTITES LHERZOLITE West African Craton Séguéla Côte d’Ivoire 

分 类 号：P58[天文地球—岩石学]