Precambrian Crustal Development in Western Nigeria: Indications from the Iwo Region

Hubbard, F. H.

doi:10.1130/0016-7606(1975)86<548:pcdiwn>2.0.co;2

Cited by 70 publications

(23 citation statements)

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“…Our study confirms the assertion of Hubbard (1975) and Cooray (1977). The field relationships in the Oban Massif and the Obudu Plateau as well as petrography and geochemistry of the analyzed charnockitic rocks show that these are hypersthene-bearing gneisses which formed during granulite-facies metamorphism (Ekwueme and Krö ner, 1998).…”

Section: Discussionsupporting

confidence: 95%

“…The idea of a once-extensive granulite-facies metamorphism as represented by the widespread occurrence of charnockitic rocks (Hubbard, 1975) has been rejected by most authors who considered that charnockites in the Nigerian basement are all of magmatic origin and intruded into the migmatitegneiss complex (Orajaka, 1971;Rahaman and Ocan, 1978;Tubosun et al, 1984). Cooray (1977) classified the charnockitic rocks of Nigeria following the scheme of Streckeisen (1974) and suggested that because of their foliated nature, the charnockites are metamorphic rocks and should be termed hypersthene gneiss, hypersthene granulite, charnockitic gneiss or charnockitic granulite.…”

Section: Discussionmentioning

confidence: 99%

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Single zircon ages of migmatitic gneisses and granulites in the Obudu Plateau: Timing of granulite-facies metamorphism in southeastern Nigeria

Ekwueme

Kröner

2006

Journal of African Earth Sciences

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Section: Discussionsupporting

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Single zircon ages of migmatitic gneisses and granulites in the Obudu Plateau: Timing of granulite-facies metamorphism in southeastern Nigeria

Ekwueme

Kröner

2006

Journal of African Earth Sciences

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“…This particular schist belt has been recognized as a Pan-African ensialic mobile belt derived from an aulacogen, and is connected with the ocean [1]- [4]. The basement complex rocks of Iwaraja area represent one of the important areas in understanding late stages of the Pan-African orogeny (600 ± 150 Ma) within the southwestern Nigerian.…”

Section: Introductionmentioning

confidence: 99%

Structural Geology of the Basement Complex Rocks in Iwaraja Area, Southwestern Nigeria

Adeoti

Okonkwo

2016

ILNS

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Abstract. The geological and structural evolution assessment of the Basement Complex rocks in Iwaraja area, southwestern Nigeria showed that the basement rocks comprise quartzites and quartzschists of the Effon Psammite Formation, quartz-mica schists, biotite schists, migmatitic gneisses, granitic gneisses, late and post-tectonic granitic rocks including pegmatites, which have been subjected to two phases of deformation. The first phase is mainly a fabric forming deformation that also led to the development of moderately plunging mineral lineation. No minor fold of this phase was recognized. The second deformation phase gave rise to the development of Iwaraja (ductile) shear zone. The mylonitic foliation is sub-vertical and steeply dipping and while the mineral lineation is sub-horizontal and shallowly plunging. Within granitic gneiss mylonites, the shear zone is characterised by early and late open to tight folds of pegmatite dykes. Adjacent the shear zone, ptygmatic folds of quartzo-feldspathic veins in gneisses and crenulated cleavages that overprinted earlier schistosity surfaces in the quartz-mica schist also characterised this deformation phase. Extensional fractures in the various lithologies generally show bimodal orientations mainly in the WNW-ESE and NW-SE directions, which are nearly perpendicular to the regional metamorphic foliations. These deformation conditions depict structural features that are associated with internal zones of orogenic belts. Within the study area, the structures document late-Precambrian deformation during the closing stages of Pan-African orogenesis.

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“…The study area lies west of the Ifewara Fault Zone (IFZ) [13] [14], within the Ilesa schist belt; in which talc bodies are known to be closely associated with amphibolites, quartzite and pelitic schists [9]. The talcose rocks Figure 1.…”

Section: Field Relationship and Petrographic Featuresmentioning

confidence: 99%

Compositional Features and Industrial Assessment of Talcose Rocks of Itagunmodi-Igun Area, Southwestern Nigeria

Olajide-Kayode¹,

Okunlola²,

Olatunji³

2018

GEP

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Talcose rocks from Itagunmodi and Igun areas within the Ilesa Schist Belt, southwestern Nigeria, were studied to determine their compositional affinities and industrial properties. The talcose bodies occurred as lensoid enclaves closely associated with amphibolites and quartz-mica schist. Petrographic and X-ray diffraction-aided mineralogical studies reveal that the talcose rocks are of the talc-chlorite schist variety composed predominantly of talc (average 73.63%), subordinate chlorite (average 16.08%) and accessory lizardite (average 6.5%). Total whole rock characterization of the samples using Lithium Fusion digestion revealed high mean concentrations of SiO 2 (57.53%), MgO (24.84%) and Fe 2 O 3 (7.73%) with significant enrichment of Ni, Co and Cr; and low values of Ba, Rb, Sr, V, Cu and Pb. The talc-chlorite schists plotted in the peridotitic komatiite field of the Al 2 O 3 -(FeO + TiO 2 )-MgO diagram. Water Absorption Capacity ranges from 6.25% -8.20%, Loss on Ignition is 4.8% -6.1% while Linear Shrinkage is 1.25% -1.70% and firing colour is brown to dark-brown. The overall compositional features of the talcose rocks of the area, which were hitherto uncharacterized, show their suitability as raw materials for paint, coloured pottery, ceramic insulation, textile, rubber and plastic manufacture with varying beneficiation requirements. Their high trace element content however, makes them unsuitable for use in pharmaceutical and cosmetic applications.

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Precambrian Crustal Development in Western Nigeria: Indications from the Iwo Region

Cited by 70 publications

References 0 publications

Single zircon ages of migmatitic gneisses and granulites in the Obudu Plateau: Timing of granulite-facies metamorphism in southeastern Nigeria

Single zircon ages of migmatitic gneisses and granulites in the Obudu Plateau: Timing of granulite-facies metamorphism in southeastern Nigeria

Structural Geology of the Basement Complex Rocks in Iwaraja Area, Southwestern Nigeria

Compositional Features and Industrial Assessment of Talcose Rocks of Itagunmodi-Igun Area, Southwestern Nigeria

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