جامعة الملك عبدالعزيز

KING ABDULAZIZ UNIVERSITY

Faculty of Earth Sciences

Document Details

Document Type : Thesis 
Document Title :
STRUCTURE AND DEFORMATION HISTORY OF AL-HAMAT AND HANBIQ SHEAR ZONES, NORTHERN ARABIAN SHIELD
التاريخ التركيبي و التشوهات لمنطقة تحزز الحمض و حمبق, شمال الدرع العربي
 
Document Language : Arabic 
Abstract : This study will investigate the deformation associated with the Al-Hamat and Hanbiq shear zones, NW Saudi Arabia, to establish these relationships. Most of these shear zones (e.g. Al-Hamat shear zone (AHSZ)) is associated with the Najd Fault System (NFS). The NFS (600 to 540 Ma) is a complex set of left-lateral strike-slip faults that strike NW-SE across the Arabian Shield. Other shear zones (e.g. the Hanbiq shear zone (HSZ)) trend N-S is associated with the Hejaz tectonic event (1000-620 Ma), which is characterized by a braided structural pattern of NS-trending structures. In view of the problems outlined above, this study will investigate the present initial results on the deformation of the rocks across the AHSZ and HSZ shear zones in NW Arabian Shield. Many shear systems in this region have also been reactivated under low-temperature conditions. It is crucial therefore to determine the conditions under which progressive deformation and associated microstructures have formed. The metamorphic grade decreases from amphibolite grade hornblende-bearing schists to greenschist grade chlorite-muscovite-quartz schists. The primary aims are to determine kinematics, relative timing and deformation conditions of shear zones present in the NW Arabian Shield. Remote sensing, field and microstructural analysis across the study area will assist in the definition of the relationships between these ductile-to-brittle deformation zones, which may be either cross-cutting (overprinting) or synchronous. The outcome of this study demonstrated that overprinting of the N-S trending, sinistral shear zone by the N-W trending AHSZ and they showed a deflection of the AHSZ where it meets the N-S trending structure. This led to the conclusion that the HSZ is an older structural weakness that existed before the Najd deformation and that the HSZ and AHSZ are not conjugate sets. HSZ belongs, in general, to the older N-S trending fabrics, who are related to the Hejaz orogeny and predates the NFS by 100 Ma.  
Publishing Year : 2007 AH  
Added Date : Sunday, November 23, 2008 

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