التحليل التركيبي و التكتوني لطيتي بعشيقة و الفاضلية المحدبتين-شمالي العراق

الملخص EN

The present work includes structural analysis and synthesis of Bashiqa and AL-Fadhlya Anticlines, located (25) km northeast Mosul City – northern Iraq.

These structures extend in NW – SE trend for about 25 km within the Foreland Fold Belt of Iraq.

Geometrical classification of these folds based on stereographic analysis refers that they were developed by horizontal compressive stress in NE – SW direction.

Furthermore, Fourier analysis revealed that SW limbs of both folds are relatively more developed than their NE limbs.

This might be ought to higher stress intensity developed within SW limbs of both Anticlines.

Such a higher stress intensity expressed in further flexure of SW limbs a round secondary hinges, multi reverse slip faults in SW limb of Bashiqa Anticline, local overturning and minor folding in SW limb of AL-Fadhlya Anticline.

The study also revealed a marked variance in detachment depth and shortening percentage between these structures.

Bashiqa is deeply detached and less shortened than AL-Fadhlya.

Detachment depth variance might be attributed to inversely reactivation of two en – echelon arranged, varied depth, Foreland verged detached faults beneath Bashiqa and AL-Fadhlya folds.

Inverse reactivation of these detachment faults during compressive phase led to differential folding and hence detachments of the two folds across a dextral subsurface strike slip fault transverse to these folds.

The later one may play as an accommodation fault for differential reverse movement on the varied depth detachment faults beneath these folds.

However, wide hinge area of Bashiqa Anticline, disruption of its both limbs by many reverse slip fault have contributed in depletion a considerable amount of shortening compared with AL-Fadhlya Anticline shortening.

التحميل التركيبي و التكتوني لطيتي بعشيقة والفاضمية المحدبتين – شمالي الع ا رق 89 The structural model proposed here for Bashiqa and AL-Fadhlya Anticlines is such that: the transversal subsurface strike slip faults (SF3, SF4 of Mutab, 2000) are lateral ramps of Foreland verged detachment faults beneath these structures.

The main reverse slip faults on both limbs of Bashiqa fold and that one disrupting (SW) limb of Maqlub Anticline, might linked at depth with the proposed main detachment fault deep seated under Bashiqa structure.

Inverse reactivation of this as well as the other shallower under AL-Fadhlya Anticline together with resulting synthetic and antithetic reverse slip faults have effectively contributed in folding process and its style in this area.