| dc.description.abstract | This Research was conducted in the Ikanga area, which occurs at the intersection of longitude
38o33’50’’E and latitude 1.7o25’45’’ S in Kitui County, south-eastern Kenya. The Area lies within the
Neoproterozoic Mozambique Belt in which the iron formation deposit, which is the main focus of
this study occurs. The deposit is, approximately 250km away from the city of Nairobi. This study
was conducted purposely to assess the iron formation deposit in the Ikanga area and find out whether
it has some economic value or not. The area is a gently low undulating semi-arid land with acacia
tree family and dry drainage system. The rock types of the area are Neoproterozoic in age and
include granitoid gneisses which are dominant. On the local scale, granitoid, feldspathic gneisses,
kunkar limestone, migmatite, lateritic-silica-baked-ferrous-canga and marble do occur. Alluvial
sandy soil deposits of Pleistocene and Recent Age, which include red and black soils, form the local
geology of the study area. In pursuance of this research, the following methods were applied: 1).
Remote Sensing; 2). Ground Magnetic Survey; 3). Geochemical Analysis; 4). Mineralogical and
Petrographical Analyses; and 5). Data Analysis using Software Applications. Application of these
methods showed varied results. Remote sensing gave a broad pictorial view of the study area and its
surroundings and identified where the iron formation deposit is concentrated for favorable sampling
point sections prior to the field work. The Landsat Band etm+3:1 ratio for iron oxide displayed the
dispersion of the iron formation in the study area. The ground magnetic method was able to
determine the magnetic fields of the area. A proton precision magnetometer was employed in this
geophysical mapping to collect total magnetic field in the area. Analysis of the total magnetic intensity
(TMI) of the area and associated magnetic source results mark the locations and orientations of
southwest-northeast trending linear structures at depth caused by shearing and subsequent mineral
alterations. The areas occupied by magnetic highs to the east are interpreted to coincide with locations of
iron formations and require ground follow-up and truthing. Geochemical data analyses confirmed
predominantly oxide facies mineralization with Fe2O3 as the main iron oxide. The highest non-iron oxide
amounts in the domain include TiO2 (≤9.72 wt% in the soil), MnO (≤ 0.2 wt% in haematite, gneiss, and
soil), CaO (≤ 54.7 wt% in limestone), Al2O3 (≤ 21.8 wt% in soil), Na2O (≤ 4.31 wt% in gneiss), K2O (≤
3.6 wt % in soil) and SiO2 (≤ 83.63 wt% in pegmatites). The Fe2O3 wt% in the hematite mineralized
samples ranges from 72.4% to 86.3% Fe2O3 wt% with an average of 76.97 Fe2O3 wt%. In gneisses the
Fe2O3 wt% ranges from 3.38 to 16.4 wt%, with an average of 8.0 wt%, while in the soil the Fe2O3 wt%
ranges from 3.9 to 79.6 wt%, with an average of 22.65 wt%. The geochemical data indicate that the
Ikanga deposit is very likely to have been derived from a Precambrian Banded Iron Formation (BIF)
precursor by the weathering processes. | en_US |
