Abstract
Al Faydh area is a major significant tectonic structure in southwestern part of Arabian shield, and it was esti-mated using finite strain analysis and microstructural investigation. Our research focuses structural features of the Al Faydh area in order to obtain field identification and better comprehend the tectonic setting for studied region. The Rf/phi and Fry techniques were used the most of quartz and feldspar for felsic minerals and biotite and hornblende for mafic minerals. The axial ratios with the mean average about 1.09-1.83 (using Rf/phi method) and 1.13 to 1.95 (using the Fry method) in the XZ section for the collected samples of metavolcanic, metasedimentary and meta-granite (gneisses). The finite strain direction displays clustering with slight plunging along a W-E trend along the long axes. The Z axes are related the sub-vertical and sub-horizontal foliation. The majority results suggest oblate strain symmetry and there is noticeable rise in strain magnitudes toward the tectonic contacts. The volume change was related the accumulation of finite strain in the different lithologies during a polyphase deformation regime. Applying the finite strain and microstructural analysis data from Al Faydh region concluded that the structural contacts for different lithologies were generated during faults, plutonic intrusion and fracture zones. Also, the deformation in the Al Faydh region are formed under brittle to semi-ductile deformational with simple shearing.