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

Ekwueme, Barth N.; Kröner, Alfred

doi:10.1016/j.jafrearsci.2005.11.013

Cited by 28 publications

(17 citation statements)

References 45 publications

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“…The metamorphic rocks in the Eastern Nigeria Terrane and the Obudu area are considered to reach metamorphic grades up to upper amphibolite facies by Onyeagocha and Ekwueme (1990), while Ferré et al (2002) and Ukwang et al (2003) concluded that metamorphism in the Eastern Nigeria Terrane extended to granulite facies. Ekwueme and Kröner (2006) have calculated a single zircon age of 574±10 Ma for gneiss of the Obudu Plateau. They conclude that the Pan-African high-grade event in the area was coeval with the formation of granulites in Cameroon, Togo and Ghana.…”

Section: Discussionmentioning

confidence: 99%

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P-T conditions of Pan-African orogeny in southeastern Nigeria

Ephraim¹,

Ekwueme²,

Moazzen³

et al. 2008

Central European Geology

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Different rock types from the area northeast of Obudu, southeastern Nigeria were investigated in order to place constraints on their metamorphic conditions. Detailed petrographic studies indicate four main rock groups in the studied area, namely migmatitic gneiss, migmatitic schist, granite gneiss and a minor amount of amphibolite, metagabbro and dolerite. The chemistry of minerals in these rocks is used to estimate metamorphic pressure and temperature (P-T) using appropriate geothermometers and geobarometers. The estimated temperature for migmatitic gneiss of the area is 600-625 °C and 600-650 °C for migmatitic schist; the pressure is ~ 8 kbar. For amphibolite the temperature is ~600-700 °C and pressure is 8-12 kbar. The estimated pressures and temperatures for the northeast Obudu rocks correspond to upper amphibolite to lower granulite facies metamorphism. The metamorphism occurred due to continent-continent collision during the Pan-African orogeny, most likely during the D1 deformational phase of the area. The recorded high pressures possibly resulted from crustal thickening in the area. P-T conditions for Pan-African orogeny in northeast Obudu area are in good agreement with P-T estimations for the Pan-African event in adjacent areas.

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Section: Discussionmentioning

confidence: 99%

“…Granulite facies metamorphic age (ca. 574 Ma) is from Ekwueme and Kröner (2006) are available) are plotted on the P-T diagram of Fig. 6.…”

Section: P-t Conditions Of Pan-african Orogeny In Southeastern Nigerimentioning

confidence: 99%

P-T conditions of Pan-African orogeny in southeastern Nigeria

Ephraim¹,

Ekwueme²,

Moazzen³

et al. 2008

Central European Geology

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“…The migmatite gneiss complex is a heterogeneous assemblage of predominantly amphibolite facies migmatites, orthogneisses, paragneisses and basic to ultrabasic rocks (Rahaman,1988). The migmatite -gneiss is dominantly made up of quartzo -feldspathic gneiss that are predominantly biotite and / or hornblende -bearing and rarely pyroxene (Ekwueme and Kroener, 2005;Ukwang et al, 2003). The schist belts, believed to overlie the migmatite gneiss complex and consisting mainly of psammitic to politic metasediments with minor occurrences of banded iron formation, marbles and amphibolites with the latter being interpreted as metavolcanic (Turner,1983;Elueze and Okunlola, 2003).…”

Section: Geologic Setting Of the Areamentioning

confidence: 99%

“…The pegmatites which are believed to be late Pan-African (600  150Ma) host considerable rare metals such as Ta, Nb, Sn, Li and W mineralization (Okunlola and Solomon Jimba,2006). Isotopic data have revealed that the Basement Complex has been involved in several tectonothermal events, which include from the oldest Liberian, Eburnean, and Pan African (Grant et al 1972;Ekwueme, 1987;Rahaman, 1988;Ekwueme and Kroener 2005).…”

Section: Geologic Setting Of the Areamentioning

confidence: 99%

Preliminary investigation of pegmatites in Obudu Area, Southeastern Nigeria, using stream sediments geochemistry

Edem¹,

Ekwueme²,

Ephraim³

et al. 2016

Glo Jnl Pure Appl Sci

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Stream sediments of Obudu Plateau were investigated with a view to elucidating their geochemical features, mineralization potentials and element concentrations. Stream sediment samples were collected from Southern Obudu Plateau area and analyzed for 22 elements, comprising major and trace elements, using Inductively Coupled Plasma -Mass Spectrometry (ICP-MS). The data obtained were statistically treated. Ba, Sr, Nb, Co, Pb, Ta and Na show moderate to high concentrations, when compared with threshold values of these elements. The concentrations of these elements in sediments of Southern Obudu show low mineralization potentials of pegmatites of the Obudu Plateau. The elements in Obudu stream sediments show perfect, strong, moderate and weak correlations among themselves, indicative of variations in their mobility.

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“…The area is a prolongation of the Cameroon Mountain into the Cross River plains (Ekwueme & Kröner, 2006;Efiong, 2011;Amuyou, Eze, Essoka, Efiong & Egbai, 2013 (Edet & Okereke, 2005). Elevation ranges between 150m and 1600m above the local topography which is over 200m above mean sea level.…”

Section: Study Areamentioning

confidence: 99%

Spatial Analysis of Land Surface - Vegetation Relationship in Mountainous Areas of the Tropics Using Srtm-3 Dem

Efiong¹,

Digha²,

Asouzu³

2016

JGG

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Digital elevation models (DEMs) have shown much potential for use in the extraction of land surface parameters and analysis of the relationship between land surface units and vegetation cover. However, there is lack of studies on the use of SRTM-3 DEM in vegetation studies of mountainous regions. This study is therefore an attempt to relate land surface parameters to vegetation cover in the Obudu mountain region using SRTM-3 DEM and Landsat data. Geomorphometric classification of the land surface was done using an unsupervised ISOCLUST algorithm while vegetation cover classification was done using the supervised approach based on the Maximum Likelihood algorithm. The resultant land surface units and vegetation cover maps were then related using grid-based statistic within the geographic information systems. The overall measure of difference between the two maps yielded a chi-square (d.f. = 24) = 1.9154, p > 0.05. This implies that there is no significant difference between the land surface units and the vegetation cover in the study area. This findings support the use of SRTM-3 for land surface and vegetation mapping where there is no higher quality data, or the cost of obtaining one is inhibitive; a situation that is faced by many developing economies like Nigeria. However, this results should be interpreted and used within the context of the uncertainty that is contained in the SRTM-3 DEM.

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

Cited by 28 publications

References 45 publications

P-T conditions of Pan-African orogeny in southeastern Nigeria

P-T conditions of Pan-African orogeny in southeastern Nigeria

Preliminary investigation of pegmatites in Obudu Area, Southeastern Nigeria, using stream sediments geochemistry

Spatial Analysis of Land Surface - Vegetation Relationship in Mountainous Areas of the Tropics Using Srtm-3 Dem

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