Structural Analysis for Qazzaz Metamorphic Core Complex, Northwestern Arabian Shield, Saudi Arabia

Abstract

Identifying deformational mechanisms and associated structures at various scales, ranging from regional-scale structures to microscopic fabric, is crucial for the assessment of tectonic development. Thirty-three samples were taken from the Qazzaz metamorphic core complex to estimate the finite strain for felsic and mafic minerals. These samples included gneisses rocks, monzogranite, and metavolcano–sedimentary rocks for both the Thalbah and Bayda groups. Using the Rf/j and Fry methods, the axial ratios (XZ) range about 2.20 to 7.10 and 1.90 to 9.10, respectively. For various rock units, the strain measurements show moderate to highly deformation. Most of the observed samples show shallow WNW dipping along a N to WNW trend of finite strain (X). The short axes (Z) based to be subvertical foliation related with a subhorizontal foliation. The results demonstrate that contacts generated at semi-brittle to ductile deformation and that the strain of magnitude has the same value for different lithologic units. It concluded that nappe generation in orogens results from pure shear deformation.