Application of Fry Strain Analysis Technique on Metasediments Arround Danko Area, Sheet 74sw, Part of Zuru Schist Belt, Northwestern Nigeria

Abstract

The study area (Danko) is a part of the Zuru Schist Belt that comprises of Archean and Proterozoic rocks bearing the imprints of the Liberian, Eburnean and Pan-African orogenic events. Three deformational events have been identified (D1, D2 and D3) to have affected the rocks of the study area. The study uses Fry strain analysis method to digitize the center of the grains from which axial ratios and angles to reference lines of fifteen photomicrographs from low grade metasedimentary rocks (quartzites and muscovite schist) so as to understand their deformation pattern and strain history. Quartzite recorded a more intense strain history while muscovite schist recorded a slightly constrictive strain. This study attributes the discrepancy in strain values to be the result of a ductily contrast between the rock types. The majority of the strain in these rocks appears to come from D2 deformation due to the nearly vertical long axis of strain and corresponding field evidence and also shows that there is heterogeneity in bulk strain.