Geochemistry of Amphibolites in Akom II, Nyong Series, North Western Border of the Congo Craton, South Cameroon

Beyanu Anehumbu Aye,Primus Azinwi Tamfuh,Enerst Tata

doi:10.14419/ijag.v9i1.31467

Beyanu Anehumbu Aye, Primus Azinwi Tamfuh + Show 1 more

Open Access

https://doi.org/10.14419/ijag.v9i1.31467

Copy DOI

Abstract

The garnet amphibolites, from the Akom II area in the Archaean Congo Craton, were examined to determine the geochemical affinity and tectonic environment. The study uses mineral assemblages and whole-rock geochemistry to identify the geochemical affinity and tectonic setting of the amphibolites associated with monzogabbro and pyroxenites. The studied rocks of Akom II are garnet amphibolites. Mineralogically, the rocks contain hornblende + plagioclase + garnet Â± quartz Â± epidote Â± apatite Â± opaque, indicating that they could have been formed from a basic igneous protolith. The geochemical signature indicates that the rocks are tholeiitic in nature. They are similar to the metamorphosed equivalents of ocean island basalts (OIB), with characteristics typical of Volcanic Arc-Basalt (VAB). The geotectonic diagrams confirm the tholeiitic nature of these amphibolites. High field strength elements ratios (Nb/Ta) range from 14-16, which corresponds to Volcanic Arc Basalt (VAB). The primitive mantle normalized patterns of these rocks show negative anomalies in Ta and Ti suggesting a geotectonic signature characteristic of a subduction zone, consequently suggesting the existence of a suture zone in the study area.Â Â Â

Highlights

Amphibolites, amphibolitic gneisses, and calcic gneisses usually form remnants of greenstone and metamorphic belts (Wang et al 2008, Kakar et al 2014, Tushar M Meshram et al 2017)
Penaye et al 1989 described the amphibolites as Paleoproterozoic; Munyanyiwa et al 1997 attested that the amphibolite facies of the Zambezi belt were Neoproterozoic
This paper investigates the petrography, mineralogy and geochemistry of amphibolites of the Nyong unit

Summary

Introduction

Amphibolites, amphibolitic gneisses, and calcic gneisses usually form remnants of greenstone and metamorphic belts (Wang et al 2008, Kakar et al 2014, Tushar M Meshram et al 2017). They occur in the most diversified geotectonic environments of the planet from the Archaean to the Phanerozoic (Bicalho et al 2019). Several studies were conducted within the Nyong unit of the Archaean Congo craton (Ebah Abeng et al 2012, Aye et al 2017) yet no one settles the geochemical affinity and tectonic environment of the rocks. It is intended to identify the geochemical affinity and tectonic environment of the generation of amphibolites in this area

Results

Discussion

Conclusion