Department of Geography

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Browsing Department of Geography by Author "Abdurrahman, Ibrahim Bukar"

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    petrographic and geochemical properties of pegmatites of TUDUN AMAMA HILL, SHEET 208NE CENTERAL NIGERIA
    (Department of Geography, Nasarawa State University Keffi, 2018-08-01) Abdurrahman, Ibrahim Bukar
    A geological field mapping was carried out in some part of Keffi covering Tudun Amama to Maloni Hill covering approximately 4sqkm to study the petrographic characteristics of the rocks and pegmatites. The aim of the field geological mapping is to study pegmatites, how they intrude and the host rock in which they intrude on, mineralogy and petrology, their mode of occurrence, characteristics, recognizable features on them, as well as the natural relationship between these rocks and the topography of the study area, and to use the information to give their origin. In order to obtain accurate field result and a successful completion of this project work, various methods and procedures were used systematically. The mapping was carried out using a base map of the area on a scale of 1:50,000 and shows that granite gniess, biotite gniess, schist and pegmatites compere the in the area. The petrographic of the rocks consists of its ground mass, crystal properties and rock fragments. Geochemically the pegmatites consist of major element compositions approximating "granite", however, when found in association with granitic plutons it is likely that a phlegmatic dike will have a different trace element composition with greater enrichment in large-ion lithophile (incompatible) elements, boron, beryllium, aluminum, potassium and lithium, uranium, thorium, cesium etc. Occasionally, enrichment in the unusual trace elements will result in crystallization of equally unusual and rare minerals such as berxl. tourmaline, columbite, tantalite, zinnwaldite and so forth. In most cases, there is no particular genetic significance to the presence of rare mineralogy within a phlegmatic, however it is possible to see some causative and genetic links between, say, tourmaline-bearing granite dikes and tourmaline-bearing pegmatites within the area of influence of a composite granite intrusion.