Home / Current Issue / Paper 1709255
Assessment of Deformation Patterns On Pan-African Basement Rocks of Keffi Area (Sheet 208NE), Central Nigeria
Subject area: Physical Sciences and Environment · Area of research: Geology
Abstract
The study analyzed field structural measurements and aeromagnetic data over parts of Keffi, central Nigeria, to assess surface deformational signatures and deep buried lineaments associated with the Pan-African structural system. The lithomorphology of the area reveals a cluster of reconstituted geomorphological terrains, initiated by the collage of multiple tectono-deformational dynamics. These are characterized by polydeformed phyllitic schist, biotite granite with patches of granodiorite, porphyroblastic and migmatized gneisses, among other minor lithologies, all of which formed primarily during the Pan-African tectonics. The analysis of aeromagnetic data shows lineaments that are linear to curvilinear, predominantly in NE-SW directions, with a marginal NW-SE trend. The NE-SW lineaments exhibit significant lengths, measured in thousands of meters, and crisscross other trends. These lineaments are correlated with trends of structurally controlled pegmatite, stretched phenocrysts, xenoliths, and magmatic enclaves on granitic plutons. Field data reveals ductility defined by foliation, lineation, and minor shear zones that cluster around NW-SE, NE-SW, and a faintly superimposed E-W trend. These structures are defined by concordant and discordant mineral growth and the transposition of stratigraphic fabrics. The intensity of the deformation varies, ranging from mere schistosity to well-developed gneissoid structures in some components of the rocks. Foliation displays polyphase deformation and reveals lateral disparity, indicating a bulk directional rock deformation pattern parallel to plutons and gradational around contacts with gneisses. Meanwhile, lineation shows a single-phase deformation predominantly in the NE-SW direction. The brittle system exhibits NE-SW, NW-SE, and E-W trends of fracture surfaces defined by a sinistral strike-slip displacement system. This deformation pattern occurred during the later stage of an active deformational phase and was accompanied by the release of remnant fluids trapped within the cooling granitic rocks, as well as recovery attempts of the rocks under plastic stresses. This phase is chronologically the most recent in the deformation of the rocks in this area. The Pan-African tectonics in this region are considered to be interactively pervasive in nature and have significantly influenced magmatic and thermometamorphic activities.
Keywords
Pan African Tectonics, Basement Complex, Deformation
How to cite this paper
@article{1709255,
author = {Agbo, P., Goki, N. G., Tanko, I. Y},
title = {Assessment of Deformation Patterns On Pan-African Basement Rocks of Keffi Area (Sheet 208NE), Central Nigeria},
journal = {Iconic Research And Engineering Journals},
year = {2025},
volume = {8},
number = {12},
pages = {1076-1085},
issn = {2456-8880},
url = {https://www.irejournals.com/formatedpaper/1709255.pdf},
abstract = {The study analyzed field structural measurements and aeromagnetic data over parts of Keffi, central Nigeria, to assess surface deformational signatures and deep buried lineaments associated with the Pan-African structural system. The lithomorphology of the area reveals a cluster of reconstituted geomorphological terrains, initiated by the collage of multiple tectono-deformational dynamics. These are characterized by polydeformed phyllitic schist, biotite granite with patches of granodiorite, porphyroblastic and migmatized gneisses, among other minor lithologies, all of which formed primarily during the Pan-African tectonics. The analysis of aeromagnetic data shows lineaments that are linear to curvilinear, predominantly in NE-SW directions, with a marginal NW-SE trend. The NE-SW lineaments exhibit significant lengths, measured in thousands of meters, and crisscross other trends. These lineaments are correlated with trends of structurally controlled pegmatite, stretched phenocrysts, xenoliths, and magmatic enclaves on granitic plutons. Field data reveals ductility defined by foliation, lineation, and minor shear zones that cluster around NW-SE, NE-SW, and a faintly superimposed E-W trend. These structures are defined by concordant and discordant mineral growth and the transposition of stratigraphic fabrics. The intensity of the deformation varies, ranging from mere schistosity to well-developed gneissoid structures in some components of the rocks. Foliation displays polyphase deformation and reveals lateral disparity, indicating a bulk directional rock deformation pattern parallel to plutons and gradational around contacts with gneisses. Meanwhile, lineation shows a single-phase deformation predominantly in the NE-SW direction. The brittle system exhibits NE-SW, NW-SE, and E-W trends of fracture surfaces defined by a sinistral strike-slip displacement system. This deformation pattern occurred during the later stage of an active deformational phase and was accompanied by the release of remnant fluids trapped within the cooling granitic rocks, as well as recovery attempts of the rocks under plastic stresses. This phase is chronologically the most recent in the deformation of the rocks in this area. The Pan-African tectonics in this region are considered to be interactively pervasive in nature and have significantly influenced magmatic and thermometamorphic activities.},
keywords = {Pan African Tectonics, Basement Complex, Deformation},
month = {June},
}