A Review of the Structure and Evolution of the Northern Parts of the Igarra Schist Belt, Southwestern Nigeria
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Northern part of Igarra Schist Belt typifies the Basement Complex rocks of southwest Nigerian, which is part of a larger West African shield. It constitutes the northern closure of the Igarra Schist Belt. A multi-technique approach has been used to integrate interpreted satellite imagery and aero-geophysical data with field investigation, the objective of which is to understand structural fabric and to establish various parameters for potential mineralization in this area. Satellite imagery interpretation showed lineaments along WNW-ESE directions as the dominant trend. Aeromagnetic data brought out presence of dominant WNW-ESE magnetic linear, with minor ENE-WSW and NNE SSW trends. Aero-radiometric data show overall radio-elemental distribution for various litho-units and hence their contacts; interpreted results indicate E-W and WSW – ENE dominant trends of lineaments. Field investigations revealed that there are five main lithological units in the study area including migmatites, biotite schist, quartz schist, granite gneiss and calc silicate gneiss. At least three successive geotectonic episodes can be structurally distinguished in the study area: the first is captured in relics of meta-pelitic (basic) rocks caught up in the main phase gneisses; the second episode produced the fabric in the main phase gneisses as well as metasedimentary rocks while the third episode is seen to have modified the first two episodes including the Pan African intrusive suite. Orientation of dominant foliation planes of NW-SE and NE-SW in the southeast and southwest respectively of the study area gives an outline of the two opposite limbs of a fold; late-stage, brittle-ductile deformation resulted in the compression of this fold structure and subsequent faulting in one of the limbs.
Publication Info:
Author: Ajigo, I.O., Ademeso, O.A. and Odeyemi, I.B.
Volume: 56
Issue: September
Published By: Journal of Mining and Geology, 2024-09-01