Magnetic Studies of Iron Ore Mineral Deposits in Mbeu Area, Meru County, Kenya
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Iron industry in Kenya is dependent on imported raw materials. Local deposits of iron ore have been identified at various places in the country but not much has been done to determine whether the deposits are viable in quantity and quality for commercial exploitation. The location and delineation of the iron deposits and formation in the Mbeu area appraises the potential of such mineralization. Ground magnetic survey of Mbeu area was conducted to investigate subsurface geology on the basis of the earth‟s magnetic field resulting from the magnetic properties of the underlying rocks. The total field magnetic data were recorded using a high resolution proton precession magnetometer. Magnetic anomaly data running through 89 transverses were recorded. Diurnal correction (daily variations) was done by taking readings at fixed base stations periodically and the data qualitatively analyzed and interpreted. The results gave values for the total magnetic field of the ground. The results from the residual magnetic values drawn from the plotted profiles and the 3D magnetic anomaly map indicate that most predominant iron trends are North-North West – South East of the Mbeu-Meru region of Kenya. Magnetic anomalies were qualitatively discerned from the magnetic intensity contour map obtained. In this study we delineated the subsurface structures within an area of about 20km2. Qualitative analysis of the Total Magnetic Intensity map, topographic map and 3D magnetic anomaly map revealed a highly magnetic region trending North West – East, and South West – North East represented by distinct positive magnetic anomaly highs. These suggest presence of ferromagnetic material or iron bearing minerals within the basement rocks and sediments. A relatively low magnetic anomaly region exists centrally in the region trending to the south inferring a low magnetic area resulting from effects of weathering or deep seated intrusions. Modeling of selected profiles was done revealing the presence of bodies of high magnetic anomaly. These bodies displayed a magnetic susceptibility varying from 2.405611 SI units to as low as -0.892132 SI units suggesting that the area is rich in ferromagnetic minerals. The lowest values are found to the western and southeastern parts. This suggesting a low ferromagnetic content or that these minerals are at a certain larger depth in these areas. The level of distribution of the iron ore rich minerals and likely source of sediments of iron deposits was determined and models obtained are considered reasonable as they much well with the geology of the area. The region has thus been discerned to be rich in ferromagnetic mineral content and recommendations for more detailed geochemical, geological and geophysical be embraced with regard to mining prospects of iron in the area.