Mechanical versus kinematical shortening reconstructions of the Zagros High Folded Zone (Kurdistan Region of Iraq)
- Author(s)
- Marcel Frehner, Daniel Reif, Bernhard Grasemann
- Abstract
This paper compares kinematical and mechanical techniques for the palinspastic reconstruction of a folded belt in collision orogens. The studied area and the reconstructed NE-SW-trending, 50 km long cross-section is located in the High Folded Zone of the Zagros fold-and-thrust belt in the Kurdistan Region of Iraq. The present-day geometry of the cross-section has been constructed from field as well as remote sensing data. In a first step the structures and the stratigraphy are simplified focusing on the identification of the main geometric and rheological parameters controlling the deformation. In a second step, the folding process is numerically “unfolded” resulting in the ideal case in sub-parallel, subhorizontal pre-folding layering. During this dynamic unfolding-simulation also the mechanical properties of the layers are taken into account. We estimated the shortening recorded in the folded cross-section using kinematic models based on a length- and area-balancing, which were constructed using the dip domain method. The results of the kinematic models were compared with two different mechanical models, which consider perfectly welded layer interfaces and the layer-parallel slip respectively. The kinematic shortening estimates range from 4.5% in the SW to 17% in the NE, with a mean value of 11.8%. The shortening estimate of the dynamic unfolding-simulation allowing for interlayer slip agrees with these values, while welded interfaces between the units result in unrealistically high shortening values. We therefore suggest that interfacial slip and decoupling of the deformation along detachment horizons is an important mechanical parameter that controlled the folding processes in the Zagros High Folded Zone.
- Organisation(s)
- Department of Geology
- Journal
- Tectonics
- Volume
- 31
- No. of pages
- 16
- ISSN
- 0278-7407
- DOI
- https://doi.org/10.1029/2011TC003010
- Publication date
- 2012
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105122 Seismic, 101014 Numerical mathematics, 105101 General geology, 105102 General geophysics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/b83e5f31-61f0-49d2-b5f9-50e55efdbda5