Abstract
The study area as a part of Arabian plate is located within High Folded
Zone of the Zagros Fold Thrust Belt in the Iraqi Kurdistan region. The study
area consists of two major anticlines which are Harir and Khatibian
Anticlines. These two structures are studied along five traverses through 112
field stations in order to understand the geometry & mechanism of formation
of these folds.
In the studied area 13 formations were exposed exposed range in age
between Early Cretaceous up to the Pleistocene. The formations are:
Qamchuqa, Bekhme, Shiranish, Tanjero, Kolosh, Sinjar, Khurmala, Gercus,
Avana, PilaSpi, Fatha, Injana and Recent deposits.
Geometrical analysis of Harir fold indicated that this fold is asymmetrical
double plunging, gentle to open, non-cylindrical curvi-planar anticlinal
structure. Due to the presence of three strike slip-faults this anticline is
divided into four transversal blocks which are from NW to SE named: Batas,
Harir, Sheikh Mamudian and Ashkafta. Each part characterized by its own
structural, sedimentological, and geomorphological properties differs from
the other parts. The presence and detection of some faults are recognized
which effect the architecture of Harir Anticlinal structure.
Khatibian Anticline which is a northwestern part of Shakrok Anticline
was also studied, and most characteristic structural elements represent
asymmetry and vergency of this anticlinal fold toward northeast, which
differ from other anticlines in this area. As well as the structural indicators
gives that the Khatibian Anticline is a Tertiary part continuation of
Cretaceous Shakrok Anticline, but with effect of Strike-Slip fault between
them.
The analysis of the auto-extracted lineaments from Landsat ETM+ show
two main trends (NE-SW & NW-SE) which is coincident with the main
tectonic stresses in the area.
Detailed balanced and retrodeformable cross sections in the studied area
reveal the shortening increase gradually from northwest toward the middle
and southeastern part of Harir Anticline, which are 6.76%, 14.30% and
14.31% respectively, while the total shortening vertically due to time
decrease from up to down in different geological times: Tertiary,
Cretaceous, Jurassic, Triassic and Upper Paleozoic (14.81%, 10.29%,
9.76%, 9.67%, and 8.55%) respectively.
The depth to detachment has been calculated as ranging between 8 and
12 km. this depth supposed to be coincident with Upper Paleozoic Ora shale
Formation.
Structural model is proposed to the study area through two mechanisms,
one is the occurring slipping along detachment surface and second
mechanism is the Effect of the strike-slip faults (Tear faults) on Harir
structure.