Journal of Geosciences and Geomatics

The Nyong series at Edéa and Eseka area is located in the western edge of the Congo Craton and comprise three distinguish rock units namely: metasedimentary rocks unit (schists, garnet-rich micaschist); meta-igneous rocks unit (pyroxene-rich gneiss, garnet-rich charnockitic gneiss, charnockitic gneiss, biotite-rich gneiss, amphibole and biotite-rich gneiss, garnet and amphibole-rich gneiss, amphibolite, pyribolite, pyrigarnite, garnet-rich amphibolite) and a unit of the rocks resulting from the melt (migmatite, TTG) displaying quartzo-feldspathic segregation arising from either in situ partial melting or injection along dykes or ductile shear zones. The meta-igneous rocks derived from (i) intermediate to basic tholeiitic rocks with high TiO₂ (0.6-3.47%) contents compatible with the extensive orogenic domain and (ii) calc-alkaline protolith display high FeO*/MgO (1.5-3.31) ratios which is in accordance with the typical domain of collisional orogeny. The chemical patterns of metasedimentary rocks are those of shale. The average Nb/Y (0.004) ratio and the fractioned REE patterns suggest that the contribution of alkaline vulcanite and a continental environment can be envisaged for these metasedimentary rocks.

Journal of Geosciences and Geomatics. 2014, 2(2), 62-75. DOI: 10.12691/jgg-2-2-4
Pub. Date: May 04, 2014

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Tectono-Structural Overviews of Iron Formation of North Odisha, India

by Devananda Beura

Original Research

The famous iron formation of north Odisha belongs to the Archaean schist belt comprising of the litho assemblages including the Banded Iron Formation (BIF), Iron Ore and associated rocks. Major iron formations are confined to three different provinces located in the peripheral region encircling the granite complex, which is designated as the North Odisha Iron Ore Craton (NOIOC). These three iron ore belts are intra-cratonic basins that act as depository sites for the BIF, iron ore and associated rocks. The tectonic setting is correlated with the iron ore orogeny and suffered post tectonic deformations. The rocks of all the three belts have undergone multiple phases of deformation including folds and faults. The fold structures in successive phases are superimposed to produce numerous interference patterns.

Journal of Geosciences and Geomatics. 2014, 2(2), 57-61. DOI: 10.12691/jgg-2-2-3
Pub. Date: April 28, 2014

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Geological and Geotechnical Investigation of Gully Erosion along River Bosso, Minna, North Central Nigeria

by I. A. Okunlola, I. A. Abdulfatai, Kolawole L. L. and Amadi A. N.

Original Research

Geological and geotechnical investigation along River Bosso, Minna to determine the soil characteristics contributing to gully erosion in the area was done. Field mapping showed that granite, granite-gneiss and schist of Basement complex suite underlie the area and granite is more prominent than granite-gneiss and schist. The index test results for the natural moisture content ranges from 11.19 – 24.08%; the plasticity index ranges from 0 – 5.21%; the sieve analysis result shows that coefficient of uniformity, C_u ranges from 3.37 and 29.00 while coefficient of curvature, C_c ranges from 0.17 – 0.89; the undisturbed bulk density is between 0.87 – 1.11kg/m³ and the compacted bulk density is between 1.25 – 1.49kg/m³; the specific gravity ranges from 2.16 - 2.67. For the performance test; the compaction result shows that the optimum moisture content (OMC) ranges from 8.90 – 14.85% while the maximum dry density (MDD) ranges from 1.880 - 2.09mg/m³; the triaxial shear test result shows that the angle of internal friction is between 6⁰- 9⁰and the cohesion ranges from 28 – 42kg/m²; the permeability is between 1.42 × 10^-3and 1.93 × 10^-3cm/sec. The relatively high sand content and low plasticity of the soil is susceptible to erosion which is attributed to the dominant granitic rock of the study area with high affinity for gully erosion. The anthropogenic factors found to have contributed to gully growth are farm practice, mining activities and residential buildings on the flood plain.

Journal of Geosciences and Geomatics. 2014, 2(2), 50-56. DOI: 10.12691/jgg-2-2-2
Pub. Date: April 22, 2014

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Environmental Effects of Sand and Gravel Mining on Land and Soil in Luku, Minna, Niger State, North Central Nigeria

by Ako T. A., Onoduku U. S., Oke S. A., Essien B. I., Idris F. N., Umar A. N. and Ahmed A. A.

Original Research

The increase in the demand for sand and gravel for construction and other purposes such as flood control has placed immense pressure on the environment where sand and gravel resources occur. This study was carried out to determine the environmental effects of sand and gravel mining in Luku, North central Nigeria, using field observations and laboratory analysis of soil samples. Field work was carried out in the area to determine the physical environmental effects of mining while soil samples were analysed at the National Geo-science Research Laboratory (NGRL) of Nigerian Geological Survey Agency (NGSA), Kaduna for trace elements using X-Ray Fluorescence (XRF) method. Result of the field observations shows that destruction of landscape, reduction of farm and grazing land, collapsing river banks, deforestation and water pollution are the environmental effects that result due to sand and gravel mining in the area. Result of the chemical analysis shows that average concentrations of Pb, As, Cu, Ni, Cd, Hg, Ag and Zr are 47.8, 4.17, 50.9, 32.7, 2.48, 0.1, 0.8 and 496.1ppm respectively. These concentrations are higher than the average standard concentrations of these elements found in the upper continental crust. These higher concentrations may have very negative effects on plants and animals in the area and cause diseases such as brain and kidney damage, lung irritation, cardiac abnormality and event death to plants and animals.

Journal of Geosciences and Geomatics. 2014, 2(2), 42-49. DOI: 10.12691/jgg-2-2-1
Pub. Date: April 10, 2014

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