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| Titel |
Structural modeling of the Zagros fold-and-thrust belt (Iraq) combining field work and remote sensing techniques |
| VerfasserIn |
D. Reif, B. Grasemann, R. Faber, D. Lockhart |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250025700
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| Zusammenfassung |
| The Zagros fold-and-thrust belt is known for its spectacular fold trains, which have formed in
detached Phanerozoic sedimentary cover rocks above a shortened crystalline Precambrian
basement. Orogeny evolved through the Late Cretaceous to Miocene collision between the
Arabian and Eurasian plate, during which the Neotethys oceanic basin was closed. Still active
deformation shortening in the order of 2-2.5 cm/yr is partitioned in S-SW directed folding
and thrusting of the Zagros fold-and-thrust belt and NW-SE to N-S trending dextral strike slip
faults. The sub-cylindrical doubly-plunging fold trains with wavelengths of 5 – 10
km host more than half of the world’s hydrocarbon reserves in mostly anticlinal
traps.
In this work we investigate the three dimensional structure of the Zagros fold-and-thrust
belt in the Kurdistan region of Iraq. The mapped region is situated NE from the city of Erbil
and comprises mainly Cretaceous to Cenozoic folded sediments consisting of mainly
limestones, dolomites, sandstones, siltstones, claystones and conglomerates. Although the
overall security situation in Kurdistan is much better than in the rest of Iraq, structural field
mapping was restricted to sections along the main roads perpendicular to the strike of the
fold trains, mainly because of the contamination of the area with landmines and
unexploded ordnance, a problem that dates back to the end of World War Two.
Landmines were also used by the central government in the 1960s and 1970s in order to
subdue Kurdish groups. During the 1980-1988 Iran-Iraq War, the north was mined
again.
In order to extend the structural measurements statistically over the investigated area
resulting in a three-dimensional model of the fold trains, we used the Fault Trace
module of the WinGeol software (www.terramath.com). This package allows the
interactive mapping and visualization of the spatial orientations (i.e. dip and strike) of
geological finite planar structures (e.g. faults, lithological contacts) from digital elevation
models. The minimum vegetation cover in the investigated area allows an accurate
picking of geological planes from the digital elevation model, which has been draped
with LANDSAT and ASTER satellite images in order to enhance the contrast of
lithological contacts. Geological planes of finite extent are interpolated in the Fault Trace
module by virtual planes, which can be translated and rotated in any spatial direction.
Comparison of measured data from the field with interpolated spatial orientations
from the remote sensing data demonstrate that the calculated dip and strike values
can be reproduced within the measurements error of a geological field compass. |
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