Strain Analysis and Microstructural Study of Hamadat Core Complex, Northwestern Arabian Shield, Saudi Arabia

Abstract

The present work illustrates the structural setting in the Hamadat core complex, which located in the Midyan terrane. It is essential to understand deformational processes and products at different scales, which depend on the calculation of finite strain. To assess the tectonic development and structures in the Hamadat core complex, we use field investigation, finite strain analysis and microstructural examination. The Hamadat core complex employed the Rf/φ and Fry techniques for feldspar and mafic grains with 24 collected samples for gneisses, metavolcano-sedimentary rocks from both the Zaam and Baydah groups, deformed granodiorite for Jar-Salajah intrusion and Qazzaz granite. According to finite-strain data, the various rock units have moderate to high degree of deformation, and the axial ratios for XZ section vary from 1.80 to 4.50 for the Rf/φ technique and from 2.10 to 7.40 for the Fry technique. It concluded that the shortening axes display the subvertical related to the subhorizontal foliation. The strain data have the same main-phase foliation and similar deformation behavior. Finite strain acquired through high pressure metamorphism in this instance suggested that the contacts of nappe developed through the buildup of ductile strains. Also, during thrusting and intrusions throughout the deformation process, a building of brittle to ductile deformation was mostly caused by pure shearing in the study area.