TITLE:
Geochemical Signatures of Séguéla Peridotites in the West African Craton
AUTHORS:
Allialy Marc Ephrem, Dicko Kagou, Houssou N’guessan Nestor, Kouamelan Alain Nicaise, Coulibaly Yacouba
KEYWORDS:
Geochemestry, Peridotites, Lherzolite, West African Craton, Séguéla, Côte d’Ivoire
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.10 No.12,
December
14,
2022
ABSTRACT: 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.