Structural analysis of kosrat anticline and its tectonic implications, northeastern Iraq

العناوين الأخرى

التحليل التركيبي لطية كوسرت المحدبة و مدلولاته التكتونية شمال شرق العراق

مقدم أطروحة جامعية

Barno, Janan Mansur Gorael

مشرف أطروحة جامعية

al-Kubaysi, Manal Shakir Ali
al-Azzawi, Nabil Qadir Bakr

أعضاء اللجنة

al-Shammari, Thamir Abbas Ulwan
al-Rawi, Dhya Y.
Abbud, Muhammad R.
al-Shamma, Aysar Muhammad
Taha, Mundhir Ali

الجامعة

جامعة بغداد

الكلية

كلية العلوم

القسم الأكاديمي

قسم علوم الأرض

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2014

الملخص الإنجليزي

Kosrat Anticline structure in northeastern part of Iraq has been studied from structural and tectonic points of view.

The study area is located within the high folded zone of the Zagros Fold Thrust Belt in northeast of Iraq, between (E 44o 48' 36" – 44o 58' 12") latitude and (N 35o 54' 36" – 36o 01' 48") longitude.

The 15 Km.

tracing length of the fold and the strike of the strata are of NW-SE direction in accordance with the main trend of Zagros folds.

The exposed rocks of the studied region range in age from Lower Cretaceous up to the Middle Pliocene, comprising by Qamchuqa, Dokan, Gulneri, Kometan, Shiranish, Tanjero, Kolosh, Sinjar, Khurmala, Gercus, Pila Spi, Fatha, Injana, Mukdadiya and Bai Hassan formations. The anticline was described and classified according to the field measurements.

The relation between the axial plane and the two limbs was determined to find the symmetry of the anticline.

The southwestern limb is steeper and shorter than the northeastern one which makes it asymmetrical anticline verging towards southwest.

As the northeastern limb dips 21o and the southwestern one dips 30o.

The fold is double plunged anticline. A geometrical classification was carried out using the interlimb angle and according to Fleuty, 1964 the fold is classified to be a gentle fold. Folding Kinematics model was based on the changing of the competency of the formations to have a flexural slip fold that controlled by the compositions of the layers and the primary response of each rock unit to deformation. Many types of fractures were observed in the field, such as Veins, Fissures, Joints, Faults, Striations and stylolites.

The analysis was carried out only to Joints, Faults, Striations and stylolites. The Joints were classified and analyzed according to the relation between the Joint surface and the principal tectonic axis of the Anticline.

It showed abundant distribution of the systems (in downward order according to their III percentages) ab, hko>a, hkl as first order.

ac, bc, hko>b, hol>c, okl>c in the second order and in the third order are okl>b and hol>a which is form in the inner arc of the fold that make it unobservable in spite of being the maximum stress direction coincides with major compressive stress that formed the anticline.

The analysis revealed that the joints might be due to the influence of the main horizontal compression stress that is responsible of folding, or it might be caused by the stretching of the outer arc for the folded layers. Faults in the study area have been identified.

Dynamic analysis of the faults revealed that thrust faults are predominating over the Normal and Strike- Slip faults, which confirms the prevalence of thrusting due to Arabian Plate collision especially in the southwestern limb of the anticline.

Strike – slip faults were observed in the southwestern limb which might be sharing the same main stress direction of the thrust faults.

Normal faults could be resulted from the extension caused by the folding especially in the outer arcs of the folded layers. The observed striations reflect the sense of slip orientation by fault movement on a fault surface, the obtained field data were analyzed by using P&T method which is designed for a single fault plane data to find the direction for the compressional and extensional axis that is near to σ1 and σ3 respectively. The Stylolites were analyzed and classified geometrically and according to the relation of the host rock bedding planes.

Two sets of stylolite surfaces were recorded; one parallel to bedding planes which might cause due to of the overburden load "non-tectonic origin" and the other perpendicular to the bedding planes as a result of tectonic activity, the direction of the stylolite teeth in the perpendicular one is a good indicator for the main compressional stress direction which is towards northeast in the case of the study area

التخصصات الرئيسية

علوم الأرض و المياه و البيئة

الموضوعات

• الجيولوجيا
• العراق

عدد الصفحات

199

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-609787