Geology and Geochemistry of Iroko-Granites Southwestern Nigeria: Implication on Provenance

Updata:01-01-1970

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By:Olusola A. OlaOlorun, Segun Akinyemi, Ayomide J. Oluwaleye, Joseph Agbemuko

DOI: https://doi.org/10.30564/jgr.v2i3.2246

Abstract:
The geology, geochemistry of Iroko-granites have been studied and reported in this paper. The study area has been described as of Archaean-EarlyProterozoic terrain underlain by migmatite-gneiss-quartzite complex with supracustal rocks. Large number of granites which outcrops in Iroko-Ekiti represent a typical occurrence of granitoids sporadically distributed in the
basement and are known to belong to the Older Granite suites, which are attributable to the Pan-African Orogeny (750± 150Ma). The rocks occur,mostly as flat and low lying within sparse vegetation. Structures common on and around the outcrops include quartz vein, veinlets, pegmatite dykes which trend North-south, discrete exfoliated surfaces and xenoliths of older rocks. This study reveals that the granites belong to calc-alkalic suites,
demonstrate metaluminous nature, and exhibit characteristics of I-type granites. The granite is a distinctive type in that it is relatively highly potassic, has high FeO/(FeO + MgO) ratio, and high average Zr (299.75ppm)concentration with other high field strength elements. The trace elements study implicates pronounced fractional crystallization during evolution of the granites and thus petrogenetically discriminates as Syn-collision provenance.
References:

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