Petrographic and geochemical studies of syenite-looking Ayetoro and Sasaro plutons within Igarra Schist Belt were carried out in order to classify them and determine their tectonic setting and mineralization potential...Petrographic and geochemical studies of syenite-looking Ayetoro and Sasaro plutons within Igarra Schist Belt were carried out in order to classify them and determine their tectonic setting and mineralization potential. Petrographic study and geochemical classification revealed that while Ayetoro boss is microgranite constituting an aggregate of medium grained muscovite, quartz and biotite minerals, Sasaro stock is micromonzonite made up of medium grained albite, orthoclase, biotite, hornblende and pyroxene. Geotectonic setting showed the boss and stock are orogenic, probably derived from the same upper mantle magma as Igarra batholith that got contaminated by crustal materials responsible for their difference in lithology. Their mineralization potential showed that the massive Ayetoro microgranite with no appreciable trace-element contents cannot serve as host of any metallic deposit, and should be suitable for industrial applications. Whereas, the silicified, highly sheared Sasaro monzonite, with elevated level of some trace elements contents as Ag, Au and Cu, could harbor Ag-Au-Cu deposit.展开更多
Chemical whole-rock major oxides and some trace element analyses were done on granitic-gneiss rocks from Dagbala-Atte District,located on the southeastern margin of western Nigeria Basement Complex.This was meant to c...Chemical whole-rock major oxides and some trace element analyses were done on granitic-gneiss rocks from Dagbala-Atte District,located on the southeastern margin of western Nigeria Basement Complex.This was meant to classify the rocks and to understand the tectonic setting in order to evaluate their crustal evolution.The chemical analyses were done using inductively-coupled plasma mass spectrometer.From the results obtained,these rocks classified into calc-alkaline to shoshonite series with metaluminous to peraluminous varieties.They are I-type granitoids of feroan composition.The granitic gneisses formed from metamorphism of granite and granodiorite.Tectonically,most of the rock samples plotted in the field of island arc,continental arc and continental-collisional granitoids,which indicated that the protolith granite and granodiorite are orogenic and are arc related inferring arc tectonic setting.展开更多
文摘Petrographic and geochemical studies of syenite-looking Ayetoro and Sasaro plutons within Igarra Schist Belt were carried out in order to classify them and determine their tectonic setting and mineralization potential. Petrographic study and geochemical classification revealed that while Ayetoro boss is microgranite constituting an aggregate of medium grained muscovite, quartz and biotite minerals, Sasaro stock is micromonzonite made up of medium grained albite, orthoclase, biotite, hornblende and pyroxene. Geotectonic setting showed the boss and stock are orogenic, probably derived from the same upper mantle magma as Igarra batholith that got contaminated by crustal materials responsible for their difference in lithology. Their mineralization potential showed that the massive Ayetoro microgranite with no appreciable trace-element contents cannot serve as host of any metallic deposit, and should be suitable for industrial applications. Whereas, the silicified, highly sheared Sasaro monzonite, with elevated level of some trace elements contents as Ag, Au and Cu, could harbor Ag-Au-Cu deposit.
文摘Chemical whole-rock major oxides and some trace element analyses were done on granitic-gneiss rocks from Dagbala-Atte District,located on the southeastern margin of western Nigeria Basement Complex.This was meant to classify the rocks and to understand the tectonic setting in order to evaluate their crustal evolution.The chemical analyses were done using inductively-coupled plasma mass spectrometer.From the results obtained,these rocks classified into calc-alkaline to shoshonite series with metaluminous to peraluminous varieties.They are I-type granitoids of feroan composition.The granitic gneisses formed from metamorphism of granite and granodiorite.Tectonically,most of the rock samples plotted in the field of island arc,continental arc and continental-collisional granitoids,which indicated that the protolith granite and granodiorite are orogenic and are arc related inferring arc tectonic setting.
