期刊名称：International Research Journal of Earth Sciences
电子版ISSN：2321-2527
出版年度：2016
卷号：4
期号：6
页码：31-40
语种：English
出版社：International Science Community Association
摘要：Bauchi district is part of a large basement complex in northeastern Nigeria characterised by extensive exposures of granitoids. Field mapping of the area at a scale of 1:50,000 shows that the area is underlain by three broad lithologic units viz: migmatite/gneiess, bauchite and granites of various textures. These rocks are largely composed of hornblende, pyroxene, plagioclase, biotite, microcline, quartz with accessory apatite, zircon, sphene and magnetite in various proportions. The rocks host enclaves of various shapes and sizes and are separated from one another by predominantly gradational contacts. The distribution of enclaves throughout the granitic unit, their sub-rounded shape and transitional contacts with the host rock are consistent with their igneous texture that the enclaves are syngenetic probably representing remnants of pre-existing rocks from which the granitoids were sourced. Interpretation of both the mafic enclaves and gradational contact relationships has led to a provisional conclusion that the granitoids are probably I-type genetically related to a common source by fractional crystallisation of hornblende, plagioclase, biotite, microcline and accessory apatite, zircon and sphene. Petrochemical study is needed in order to assess more accurately the genetic relationships of the various rock units as the present study can only give an insight into this aspect.
