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Stratigraphy, Geometry, and pattern of Imbricated zones, NW Zagros Fold and Thrust Belt in Iraqi Kurdistan Region

Sirwan H. Ahmed1* 

1Geology Department, Science College, University of Sulaimani, Sulaimani, Kurdistan Region, Iraq

*Corresponding author’s e-mail:

Original: 20 November 2020 Revised: 10 January 2021 Accepted: 2 March 202Published online: 20 June 2021  

DOI link:

The High Folded and Imbricated zones are the formalized name represent the part of the Tectonic sub-division of Iraq and Kurdistan Region of Iraq (KRI). The study of compressional deformation and Stratigraphy are the keys to identify thrust faults structures and define the sequence of thrusting in High Folded and Imbrication zones as a part of Zagros Fold and Thrust Belts. Through this study, we try to describe the compressional thrust faults and stratigraphical unit description. Thrust faults make repetition of the sequences of Jurassic-Triassic Cretaceous sequence over thrust above Cretaceous sequences. In Iran-Iraq border close to Sirwan valley the large thrust faults (Sirwan-Sazan Thrust faults) identify. The fault system makes Triassic formations over-thrust the Valanginian-Albian Balambo Formations. In Balakayati area serious thrust fault exists, which creates twice repetition of Jurassic-Cretaceous formations forming imbrication thrusting system and fault propagation fold. In Bradost-Korek anticlines the Jurassic-Cretaceous formations over-thrust Cenozoic formations. In Kamosk anticline the thrust faults are in the Cretaceous formations. The dimension and the style of the thrust faults are different but generally, most of the decollement layers of the thrusting are the Early Triassic and Middle-Late Jurassic formations. The collection of all these results constrain geological cross-section in Imbricate Zone and restore to obtain the 7.5 km distance of Shortening due to folding and faulting.

Key Words: Compression stress, Imbricated zone, Thrust faults



[1] Ahmed, S., H. "Designation and Study of Anticlines- Kurdistan Region-NE Iraq". 2nd International Science Conference, IOP Conf. Series: Journal of Physics: Conf. Series 1294 (2019) 082001 IOP Publishing, doi:10.1088/1742-6596/1294/8/082001.

[2] Ahmed, S., H. "Tectonostratigraphic Evolution of the Northeastern Arabian Plate in Kurdistan since the Jurassic". PhD thesis. pp. 467, Paris 6. (2013).

[3] Ahmed, S., H., Barrier, E., Müller, C. "Basin evolution model during cretaceous in the northeastern of Arabian plate in Kurdistan region". Arab J Geosci. Vol. 9, pp. 645. (2016).

[4] Ahmed, S., H., Mohialdeen, I., Muhammed, H.,F. "Origin of the Phacoid Structures within the Chia Gara Formation, Kurdistan Region, Iraq". JZS(Part-A). Vol 22, Issue 1. (2020).

[5] Ahmed, S. H., Qadir, B.O., Muller, C. "Age determinations of Cretaceous sequences based on calcareous nannofossils in Zagros Thrust and Folded Zone in Kurdistan Region-Iraq". JZS (Part-A). Vol. 17, No. 3, (2015).

[6] Alavi, M. "Tectonics of Zagros Orogenic belt of Iran, new data and interpretation". Tectonophsics. Vol. 229, pp. 144–149. (1994).

[7] Alavi, M. "Regional stratigraphy of the Zagros fold-thrust belt of Iran and its pro foreland evolution". American Journal of Science. Vol. 304, pp. 1–20. (2004).

[8] Al-Hadidy, A., H. "Paleozoic stratigraphic lexicon and hydrocarbon habitat of Iraq". Geoarabia. Vol. 12, No. 1, pp. 63-130. (2007).

[9] Aqrawi, A.A.M. "Carbonate-siliciclastic sediments of the Upper Cretaceous (Khasib, Tanuma and Sa'di Formations) of the Mesopotamian Basin". Marine and Petroleum Geology. Vol. 13, pp. 78 1-790. (1996).

[10] Aqrawi, A.A.M., G.A. Thehni, G.H. Sherwani and B.M.A. Kareem. "Mid-Cretaceous Rudist-bearing Carbonates of the Mishrif Formation: An Important Reservoir Sequence in the Mesopotamian Basin". Iraq Journal of Petroleum Geology. Vol. 21, pp. 57-82. (1998).

[11] Aqrawi, A.A.M., Goff, J.C., Horbury, A.D., Sadooni F.N. "The Petroleum Geology of Iraq". Scientific Press, Beaconsfield, UK, pp. 424. (2010).

[12] Balaky, S.M.H. "Stratigraphy and sedimentology of Sargelu Formation (Middle Jurassic) in selected sections in Erbil and Duhuk Governorates–Iraqi Kurdistan". Master’s thesis (unpublished), Science College, University of Salahaddin, Erbil, Iraq, 109 p. (2004).

[13] Bechennec, F., Le Metour, J., Rabu, D., Bourdillon-Jeudy de Grissac, C., De Wever P., Beurrier, M., Villey, M. "The Hawasina Nappes: stratigraphy, palaeogeography and structural evolution of a fragment of the South Tethyan passive continental margin". In: Robertson, A.H., Searle, M.P., Ries, A.C. (Eds.), the Geology and Tectonics of the Oman Region. Geological Society of London, Special Publication. Vol. 49, pp. 213-223. (1990).

[14] Bellen, R.C., Dunnington, H.V., Wetzel, R., Morton, D.M. "Lexique Stratigraphique International, III". Asie, Fasc. 10a, Iraq. Centre National de la Recherche Scientifique, Paris, pp. 333. (1959).

[15] Berberian, M., & King, G., C., P. "Towards a paleogeography and tectonic Evolution of Iran". Canadian journal of earth sciences. Vol. 18, pp. 210–265. (1981).

[16] Beydoun, Z., R. "Arabian plate hydrocarbon, geology and potential: a plate tectonic approach". AAPG Studies in Geology. Vol. 33, pp. 77. (1991).

[17] Beydoun, Z., R. "Evolution of the northeastern Arabian plate margin and shelf, hydrocarbon habitat and conceptual future potential". Revue de l’Institut Français du Pétrole. Vol. 48, pp. 311–345. (1993).

[18] Blendinger, W., Van Vliet A., Hughes-Clarke, M., W. "Up doming, rifting and continental margin development during the Late Paleozoic in Northern Oman". In: Robertson, A.H., Searle, M.P., Ries, A.C. (Eds.), the Geology and Tectonics of the Oman Region. Geological Society of London, Special Publication. Vol. 49, pp. 27-37. (1990).

[19] Buday, T. and Jassim, S. "The Regional Geology of Iraq: Tectonics, Magmatism, and Metamorphism". In: Kassab, I.I. and Abbas, M.J., Eds., Geology of Iraq, Geologic Survey, Baghdad, p. 445. (1987).

[20] Buday, T. "The regional geology of Iraq. Vol. 1, Stratigraphy and Paleogeography". Dar Al-Kutub pub. University of Mosul-Iraq, pp. 445. (1980).

[21] Butler R. W. H. "Thrust Sequence". Journal of the Geological Society. Vol. 144, pp. 619-634, (1987).

[22] Chatton, M., and Hart, E. "Revision of the Tithonian to Albian Stratigraphy of Iraq". Unpubl. Report, I.P.C. Report, I.N.O.C. library, No. 1/141, 62 (2379), Baghdad. (1960).

[23] Davies, R., Casey, D., Horbury, A., Sharland, P., & Simmons, M. "Early to mid Cretaceous mixed carbonate-siliciclastic shelfal systems: examples, issues and models from the Arabian Plate". GeoArabia. Vol. 7, pp. 541–598. (2002).

[24] Dunnington, H.V. "Generation, accumulation and dissipation of oil in Northern Iraq". In, L.G. Weeks (Ed.), Habitat of Oil. American Association of Petroleum Geologists. pp. 1194-1251. (1958).

[25] El-Motaal, E., A., and Kusky, T., M. "Tectonic Evolution Of The Intraplate S-Shaped Syrian Arc Fold-Thrust Belt Of The Middle East Region". In The Context Of Plate Tectonics, the third international conference on the geology of Africa. Vol. 2, pp. 139-157. (2003).

[26] English, J.M., Lunn, G.A., Ferreira, L., Yacu, G. "Geologic evolution of the Iraqi Zagros, and its influence on the distribution of hydrocarbons in the Kurdistan region". AAPG Bull. Vol. 99, No. 2, pp. 231–272. (2015).

[27] Frehner,M Reif,D, Grasemann,B. "Mechanical versus kinematical shortening reconstructions of the Zagros High Folded Zone (Kurdistan region of Iraq)". TECTONICS. Vol. 31, TC3002. (2012). doi:10.1029/2011TC003010.

[28] Glennie, K., W., Boeuf, M., G., A., Hugues-Clarke, M., W., Moody-Stuart, M., Pilaar, W., & Reinhardt, B., M. "Geology of the Oman Mountains. Koninklijk Nederlands Geol. en Mijnbouw, Genootschap". Transactions. pp. 31. 1974

[29] Glennie, K.,W. "Cretaceous tectonic evolution of Arabia’s Eastern Plate margine: A tale of two Oceans". SEPM Spec. Publ. Vol. 69, pp. 9-20. (2000).

[30] Haq, B.U., J. Hardenbol and P.R. Vail. "Mesozoic and Cenozoic chronostratigraphy and cycles of sea-level change". Society of Economic Paleontologists and Mineralogists. Vol. 42, pp. 71-108. (1988).

[31] Hinsch,R and Bretis,B. "A semi-balanced section in the northwestern Zagros region: Constraining the structural architecture of the Mountain Front Flexure in the Kirkuk Embayment, Iraq". GeoArabia.  Vol. 20, No. 4, pp. 41-62. (2015).

[32] Hollis, C., and Sharp, I. "Albian–Cenomanian–Turonian carbonate-siliciclastic systems of the Arabian Plate: advances in diagenesis, structure and reservoir modeling". (EAGE/Geological Society of London) Petroleum Geoscience. Vol. 17, pp. 207–209. (2011).

[33] Hussain, S., H., & Aghwan, T., A. "Sedimentology and evolution of a foreland desert basin, Middle Eocene Gercus Formation (North and Northeastern Iraq)". Arab J Geosci. Vol. 8, pp. 2799–2830. (2014). DOI 10.1007/s12517-014-1352-8.

[34] Ibrahim, A., O. "Tectonic style and evolution of the NW segment of the Zagros fold – thrust belt, Sulaimani governorate, Kurdistan region NE Iraq". PhD thesis, University of Sulaimani. (2009).

[35] Jassim, S., Z., and Goff, J. "Geology of Iraq". Dolin, Prague and Moravian Museum, Burno. Czech Republic, pp. 352. (2006).

[36] Karim, K., H., Al-Hamadani, R.K., and Ahmad, S., H. "Relations between Deep and Shallow Stratigraphic Units of Northern Iraq during Cretaceous". Iranian Journal of Earth Sciences. Vol. 4, pp. 75-84. (2012).

[37] Kassab, I., I., M. "Planktonic foraminifera range in the type Tanjero Formation (Upper Campanian –Maastrichtian) of North Iraq". Jour. Geol.  Soci.  Iraq. Vol. 8, pp. 73 – 86. (1975).

[38] Kassab, I., I., M. "Some Upper Cretaceous planktonic foraminiferal genera from northern Iraq". Micropaleontology. Vol.22, No. 2, pp. 215 – 238, pls.1 – 4. (1976).

[39] Kassab, I., I., M., Al-Omari, F.S. and Al-Safawee, N.M. "The Cretaceous – Tertiary boundary in Iraq (represented by the subsurface section of Sasan well No.1, NW Iraq)". Jour. Geol. Soci. Iraq. Vol. 19, No.2, pp. 73 – 86. (1986).

[40] Konert, G., Afifi, A., M., Al-Hajri, S., A., de Groot, K., Al-Naim, A., A., and Droste, H., J. "Paleozoic stratigraphy and hydrocarbon habitat of the Arabian Plate". In Petroleum Provinces of the Twenty First Century: AAPG Memoir (Petroleum Provinces of the Twenty-First Century). Vol. 74, pp. 483-515. 2001

[41] Koop, W., Stoneley, R. "Subsidence History of the Middle East Zagros Basin, Permian to Recent". Philosophical Transactions of the Royal Society, London A305 pp. 149–168. (1982).

[42] Le Metour, J., Bechennec, F., Platel, J., P., Roger J. "Late Permian birth of the Neo-Tethys and development of its Southern continental margin in Oman". The Middle East Petroleum Geosciences. Selected Middle East papers from the Middle East Geosciences Conference, Bahrain. Vol. 2, pp. 643-654. (1994).

[43] Loosveld, R., J., H., Bell, A., Terken, J., J., M. "The tectonic evolution of interior Oman". GeoArabia. Vol. 1, pp. 28–51. (1996).

[44] Mohajjel, M., Fergusson, C., Sahandi, M., R. "Cretaceous–Tertiary convergence and continental collision, Sanandaj–Sirjan zonewestern Iran". Journal of Asian Earth Sciences. Vol. 21, pp. 397–412. (2003).

[45] Moinevaziri H. "Volcanisme Tértiaire et Quatérnaire en Iran". Thèse d’Etat, Université Paris-Sud, Centre d’Orsay, pp 287. (1985).

[46] Montenat, C., de Lapparent, A., Lys, M., Termier, G., Termier, H., Vachard, D. "La trangression Permienne et son substratum dans le Jabal Akhdar (Montagnes d’Oman, Peninsule Arabique)". Ann. Soc. Geol. Nord. Vol. 96, pp. 239-258. (1976).

[47] Naqishbandi, S., Sherwani, G., Redha, D. "Palynological Study of Ora and the Upper Part of  Kaista Formation in Zakho area,  Iraqi Kurdistan Region". Journal of Kirkuk University – Scientific Studies. Vol.5, No.1, pp. 50-74. (2010).

[48] Nowroozi, A. A. "Seismo-tectonics of the Persian plateau, eastern Turkey, Caucasus, and Hindu-Kush regions. Seismol Soc. America Bull. Vol. 61, No. 2, pp. 317–341. (1971).

[49] Perincek, D. "Sedimentation  on the  Arabian  shelf  under the control  of  tectonic  activity  in  Taurid  belt". First Petrol. Cong. Turkey. pp.  77-93. (1980).

[50] Pfiffner, O.A. "Displacements along thrust faults". Eclogae geol. Helv. Vol. 78 No. 2, pp. 313-333 Basel. (1985).

[51] Pillevuit, A. "Les Blocs Exotiques du Sultanat d’Oman. Evolution paleogeographique d’une marge passive Lexurale". Memoires Geologie Lausanne. Vol. 17, 249 pp. (1993).

[52] Ruban, D., A., Al-Husseini, M., I., & Iwasaki, Y. "Review of Middle East Palaeozoic plate tectonics". GeoArabia. Vol. 12, pp. 35– 56. (2007).

[53] Sadooni, F., N., and Aqrawi, A. "Cretaceous sequence stratigraphy and petroleum potential of the Mesopotamian basin, Iraq". In A. S. Alsharhan and B. Scot, eds., Middle East models of Jurassic/Cretaceous carbonate systems: SEPM Special Publication. Vol. 69, pp. 315–334. (2000).

[54] Saidi, A., Brunnet, M., F., Ricou, L., E. "Continental accretion of the Iran Block to Eurasia as seen from Late Paleozoic to early Cretaceous subsidence curves". Geodinamica Acta. Vol. 10, pp.189-208. (1997).

[55] Saura, E., Vergés, J., Homke, S., Blanc, E., Serra-Kiel, J., Bernaola, G., Casciello, E., Fernández, N., Romaire, I., Casini, G., Embry, J.-C., Sharp, I., R., Hunt, D.,W. "Basin architecture and growth folding of the NW Zagros early foreland basin during the Late Cretaceous and early Tertiary". Journal of the Geological Society. Vol. 168, pp. 235-250. (2011).

[56] Sengor, A., M., C. "A new model for the Late Palaeozoic–Mesozoic tectonic evolution of Iran and implications for Oman". In: Robertson, A.H.F., Seale, M.P., Ries, A.C. (Eds.), The Geology and Tectonics of the Oman Region. Geological Society of London, Special Publication. Vol. 49, pp. 797–831. (1990).

[57] Sharland, P., Archer, D., Casey, D., Davies, R., Hall, S., Heward, A., Horbury, A. and Simmons, M. "Arabian Plate sequence stratigraphy". GeoArabia Special Publication. Vol. 2, 371pp. (2001).

[58] Sharland, P., R., Casey, D., M., Davies, R., B., Simmons, M., D. and Sutcliffe, O., E. "Arabian Plate Sequence Stratigraphy". Mesozoic and Cenozoic, Enclosure 1, GeoArabia. Vol. 9, No.1. (2004).

[59] Sissakian V., K. "Geological evolution of the Iraqi Mesopotamia Foredeep, inner platform and near surroundings of the Arabian Plate". Journal of Asian Earth Sciences. Vol. 72, pp. 152-163. (2013).

[60] Sissakian, V.K., Ibrahim, E.I., Al-Waíly, I.J. "Geological Map of Arbeel and Mahabad Quadrangles". Sheets Nj-38-14 and Nj-38-15. State Co. of Geol. Surv. and Min., Baghdad. (1997).

[61] Stampfli, G., M. "Tethyan oceans". In: Bozkurt, E., Winchester, J.A., and Piper, J.D.A., eds., Tectonics and magmatism in Turkey and surrounding area: London, Geological Society of London Special Publication. Vol. 173, pp. 1-23. (2000).

[62] Stampfli, G., M., and Borel, G. D. "The TRANSMED transects in space and time: Constraints on the paleotectonic evolution of the Mediterranean domain". In The TRANSMED Atlas: The Mediterranean Region From Crust to Mantle, vol. 1, edited by W. Cavazza et al., pp. 53–80, Springer, Berlin. (2004).

[63] Stampfli, G., Marcoux, J., Baud, A. "Tethyan margins in space and time". Palaeogeogr. Palaeoclimatol. Palaeoecol. Vol. 87, pp. 373-409. (1991).

[64] Stocklin, J. "Possible ancient continental margins in Iran". In: Burk, C.A. and Drake, C.L. (eds) The Geology of Continental Margins. Springer, New york, pp. 873–887. (1974).

[65] Stoneley, R. "The geology of the Kuh-e Dalneshin area of southern Iran, and its bearing on the evolution of southern Tethys". J. Geol. Soc. London. Vol. 138, pp. 509–526. (1981).

[66] Stoneley, R. "The Middle East Basin: a summary overview".  In JBrookes, ed., Classic Petroleum Provinces, Geological Society Special Publication. Vol. 50. pp. 293–298. (1990).

[67] Takin, M. "Iranian geology and continental drift in the Middle East". Nature, Vol. 235, pp. 147–150. (1972). doi:10.1038/235147a0.

[68] Talbot and Alavi. "The past of a future syntaxis across the Zagros". Geological Society, London, Special Publications. Vol. 100, pp. 89-109. (1996).

[69] Ziegler, M., A. "Late Permian to Holocene Paleofacies Evolution of the Arabian Plate and its Hydrocarbon Occurrences". GeoArabia. Vol. 6, No. 3, pp. 445-504. (2001).

[70] Znad, R. K., S. E. Al-Khatony, Al-Sumaidaie, M., H. "Effect Of Tectonic Setting On Distribution Of Pelagic Sediment Unit (Shiranish Formation) In Zagros Foreland Basin, Iraqi Segment". Iraqi Geological Journal. Vol. 53 (2A), pp. 105 -119. (2020).