A comparative study of ree geochemistry in precambrian pegmatites and associated host rocks from western Oban Massif, Se – Nigeria

The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o27'N, and Longitudes 8o09'E and 8o18'E, south-eastern Nigeria. The pegmatites of this area have been studied by several authors for several decades till now. The present study evaluates the use of trace and rare-earth elements (REE) as finger prints in comparing the geochemistry of pegmatites and their associated host rocks, and to deduce if there is any co-genetic relationship between them. Sixteen representative samples of pegmatites and their host rocks (schist andgranodiorites) were collected and analysed using the ICP-MS analytical method. The pegmatites were found to be richer than their host rocks in SiO2, Al2O3 Na2O+K2O (alkali), Rb, Li, Cs, Be, Na, Zn, Nb, and Ga while they are poorer in Fe2O3, CaO, Sr, Ba, Zr, U, Cr, Th, and all the REEs. Only in the MgO contents are the rocks similar. Compared trace elements and REE data of schist and granodiorite (host rocks) against associated pegmatite samples in this work, show that the pegmatites are not necessarily products of their host rocks

Evaluation of hydrochemical characteristics and flow directions of groundwater quality in Udi Local Government Area Enugu State, Nigeria

A hydrogeological study was conducted at the Udi Local Government Area in south-eastern region of Nigeria to examine the hydrochemical constituent of groundwater and determine the quality for drinking and agricultural purposes. Results show that groundwater in the area is slightly acidic to slightly basic, soft and potable, when compared with the World Health Organisation standards for drinking water, and is suitable for agricultural purposes. The groundwater flow direction was determined to establish the implications of pollution from any water contamination. Twenty-one groundwater samples from existing boreholes were collected and analysed for various physicochemical parameters using standard field and laboratory techniques. Distribution of major ions was plotted on a Trilinear Piper diagram. Ajali Sandstone, known as major aquiferous layer in the area, outcrops predominately in sandy bed with medium to coarse-grained sediments. The aquifers are unconfined, semi-confined and with hydraulic conductivity values ranging from 9.0 x 10(-2) to 8.5 x 10(-2) m/day indicating medium transmissivity of groundwater in some areas and a flow net south to northward groundwater flow towards the coast. This explains why the aquifer does not appear to be very permeable and only provides a medium yield of good quality water in some regions of the study area