Abstract:
Advancement of digital image processing (DIP) and availablility of multispectral remote sensing
data have greatly aided structural geological mapping and mineral exploration. Structural mapping
of Oke-Onigbin area was carried out using combined detailed field mapping and satellite image
processing techniques. Shuttle Radar Topographic Mission (SRTM), Landsat 8 (OLI) and Sentinel
were acquired and processed using Erdas Imagine TM, ArcGIS 10.3 and ILWIS 3.8 TM softwares.
Automatic extraction method was employed for lineament extraction using PCI Geomatica
software. Geological, lineament and structural maps were produced using field and remote sensing
data. Delineated lithologies underlying the study area are migmatitic biotite gneiss, granitic gneiss,
pelitic schist, amphibolites, marble quartzites, granodiorite, granite and pegmatite. 70, 1127 and
1380 were extracted respectively from SRTM, Landsat 8 and Sentinel, showing two (200and 100),
three (300, 100 and 300) and three (300, 100 and 300) main orientation directions respectively.
Results indicate that most of the lineaments trend in the NNE-SSW direction, while others trend
in the N-S, NE-SW, WNW-ESE and E-W orientations. The histogram indicated a bimodal
distribution for SRTM, and polymodal distribution for Landsat 8 and Sentinel. Quartzite has the
highest lineament concentration while granite has the least concentration. Deformation in the area
resulted into development of both ductile structures (tight to isoclinals folds, recumbent fold, open
to close folds and kinked bands) and accompanying brittle structures (reverse, normal and strike
slip faults). The mapped structures are grouped as S1-S3 foliations, F1-F4 folds, and D1-D4
deformations. Observation of the major structural trend on the field mapping corresponds to the
lineaments extracted from remote sensing techniques. The area shows high mineralization
potential for precious metals, gemstones and industrial minerals Mineralization potential map was
produced from integration of the already produced maps.
