Document Type : Original Research Paper

Authors

1 University of Shahid Beheshti, Faculty of Earth Sciences, Department of Geology, Theran, Iran.

2 University of Tarbiat Moddares, Faculty of Basic Sciences, Department of Geology

Abstract

     Faryab area at the southeastern part of the Sanandaj-Sirjan zone, containing the Paleozoic rocks in the internal part of Zagros Orogen, displays two folding episodes through a progressive deformation event. Axial planes of recumbent F1 folds dip moderately to the north and the axes also plunge moderately to NW - SW. F1 folds were generated in a flexural-flow condition in whole lithological units. Thrust faults were produced along the overturned limbs of the F1 folds. These thrusts are most abundant in the central domain, the north of Zartorosht Au-index. At the southern edge of the central domain, displacement of large slabs of calcschist with interbedded marble were produced by these thrust faults.
Overturned limbs were cut by ductile shear zones of thrusts and development of green-schist facies in these shear zones implying the medium dips for thrusting. F2 folds were developed by co-axially refolding of F1 that are well exposed in Pasefid, Zartorosht and Zehmakan anticlines. Structural data shows the variation of F2 axis between S45W - N80W directions. Interference patterns of Z on S, M on S and S on S indicate coaxial refolding F1 by F2 (Hook Type).

Keywords

References
Ando, C. J., Cook, F. A.,Oliver ,J. E., Brown, L. D., Kaufman, S., 1983- Crustal geometry of the Appalachian orogen from seismic reflection studies .In: Hatcher ,RD., Jr., Williams,H, In (eds)Contribution to the Tectonics and Geophysics of Mountian chains, Geological socity of America Memoir 158,83-102.
 Brunel, M., Kienast, J. R., 1986- Etude petro-structurale des chevauchements ductiles himalayens sur la transversale de i Everest_Makalu (Nepal)oriental. Canadian journal of earth Sciences ,23,1117-1137.
 Butler, R. W. H., Coward, M. P., 1984 - Geolocal constraints , structural   evolution and deep geology of the northwest Scottish Caledonides.Tectonics.3,347-365.
 Hatcher, R. D., Jr., 1995- Structural Geology.Printice Hall.New Jersy,528p.
 Hatcher, R. D., Jr., 1989-Tectonic synthesis of the US Appalachians .Geological socity of America,The Geology of North America .F-2, 511-535.
 Hatcher, R. D., Jr., Hooper,R.J.,1992-Evolution of crystalline thrust sheets in the internal parts of mountain chains. In (eds) Thrust Tectonics.Chapman ,Hall,447p.
Hubber, H.,1955- Geological report on the Esfandagheh area .N.I.O.C.Geol.Rept.No,124,49p       
 Hushmandzadeh,A.,Berberian,M.,1972- The geological observation in Khabr-Dehsard area. Geol. surv. Iran. Internal report
Mohajjel, M., 1997-. Structure and tectonic evolution of Paleozoic –Mesozoic rocks, Sanandaj-Sirjan Zone, Western Iran.Ph.D
       thesis, University of Wollongong.Wollongong ,Australia (unpublished).
Ramsay, J. G., 1967- Folding and Fracturing of Rocks. McGrawHill,NewYork,568p                                   
Ramsay, J. G., Huber, M. I., 1987- The Techniques of Modern Structural Geology.Volume 2 Folds and Fructures.Academic Press, London.700p.
Sabzehi, M., 1974- Les melanges ophiolitiques de la region d' Esfandagheh ,Interpretation dans le cadre iranien.These, Universite de Grenoble,205P.
 Sabzehi, M., Berberian , M., 1972- Preliminary note on the structural and metamorphic history of the area between Dolatabad and Esfandagheh ,southern centeral Iran.Geol.Surv.Iran.Internal report.