Applications of remote sensing and geographic information system (GIS) in regional lineament mapping and structural analysis in Ikare Area, Southwestern Nigeria

Abstract

An attempt was made to use remote sensing technique to analyze some structural components of the metamorphic basement complex of the Ikare area in the SW Nigeria. Multiple data sets coupled with application of directional filtering techniques were used to extract linear features from Landsat ETM+ image with a view to improving on already produced regional structural map of the area and also determine a fast and cost effective approach to lineament mapping when handling multiple datasets. Band 7 (2.080-2.35) µm of the ETM+ image was used as a single band to visually extract linear feature while Principal Component Analysis (PCA) technique was employed in generating a multi-band enhanced image used to extract linear features. Four standard directional filters, Sobel (NS, EW, NW_SE and NE_SW) were further applied to enhance visual interpretation. The result shows that the area was affected by both ductile and brittle deformations at a regional scale, at least two episodes of deformations. A first episode of deformation (D1) produced the NW-SE tight to isoclinal fold in style (F1) and a second episode of deformation (D2) which affected the axial trace of the first episode to produce a N-S gentle to open fold (F2). Furthermore, the result shows that spatial domain filtering significantly improves the amount of lineaments that can be mapped and single band analysis is a rather fast and cost effective method of lineament extraction.

Investigating the Correlation of Tectonic and Morphometric Characteristics with the Hydrological Response in a Greek River Catchment Using Earth Observation and Geospatial Analysis Techniques

“…Additionally, in order to enhance the linear characteristics and the orientation contrast of the images (FCC and PC1), a high pass edge detection filter was applied (Figure 5a,b) [50,78,81]. PC1 reveals the information concerning the topography of the area, which, along with the edge enhancement, ideally highlights the linear elements of the image [87][88][89][90]. The final images of PC1 (along with the single panchromatic images of L7) and FCC were used for the photointerpretation process, and especially the extraction of the small-scale linear features, which are not presented in the low-resolution geological maps.…”

Retrograde Assemblages in the Muscovite-Biotite Gneiss of Oluyole Southwestern Nigeria, an Indication of Shear-Zone Environment

“…The Basement Complex of Nigeria is reported to have undergone polyphase form of deformation during the Precambrian [6][7][8][9][10][11]. More than one episode of deformation has been reported for some gneisses in southwestern Nigeria [12][13][14]. Retrograde processes have been reported to be associated with fault and shear-zone environment [15], while fluids have been linked to reducing mechanisms such as the disintegration of strong minerals into weaker minerals [16][17][18].…”