New Ideas and Critical review of Middle Eocene Gercus Formation, Kurdistan Region, NE-Iraq


  • Kamal Haji Karim Department of Geology, College of Science, University of Sulaimani, Kurdistan Region, Iraq. Author
  • Mushir M. Baziany Department of Geology, College of Science, University of Sulaimani, Kurdistan Region, Iraq. Author



Gercus Formation, Turbidite Sediment, Red Bed Series, Aeolian Sediments, Continental Sediments


In Iraq, Gercus Formation (Middle Eocene) crops out now near boundary between Low and High Folded Zone and generally consisted of red claystone and sandstone with occasional
beds of conglomerate. Lithologically, it changes toward the southwest to carbonatesiliclastics of either Khurmala or Aliji Formations inside the Low Folded Zone. All previous studies have concluded that the environment of the formation was fluvial and deltaic of continental mollasse facies with possible some shallow marine sediments at its lower part. Conversely, the most recent two studies have assigned two different, opposite environments of the formation, which are deep marine (turbidite facies), and desert environments. The aim of the present study is critical and objective analysis of the previous studies in addition to introduction of new ideas that are opposite to deep marine and aeolian environments. The study gives many evidences and features for justification of the introduced new ideas, which are revealing the actual environment of the formation. This reveal is depended on the field and regional correlation in areas of boundary between High and Low Folded Zone (area of exposure of Gercus Formation) and area of Imbricated and Thrust Zone where its equivalent in age and facies (unit five of Red Bed Series) is exposed. The present study supports neither the deep marine turbidite nor the desert erg system of the previous studies. The present study proves that the Gercus Formation consists of the distal alluvial fan and its proximal part is unit five of Red Bed.


Bellen, R. C. Van, Dunnington, H. V., Wetzel, R. and Morton, D., "Lexique Stratigraphique", Interntional. Asie, Iraq, Vol. 3c. 10a, 333 p. (1959).

Al-Rawi, Y., "Petrology and Sedimentology of the Gercus Red Bed Formation (Eocene) NE Iraq". Iraqi J. Sci. Vol. 21, 1. (1980).

Al-Rawi Y., "Origin of red color in the Gercus formation (Eocene)", Northeastern Iraq, Geology, Vol. July 1983, pp. 177–192. (1983). DOI:

Al-Qayim, B. and Al-Shaibani S., "A bimodal tidal depositional system of the Gercus Formation, Shqlawa area Northeastern Iraq". Salahadin University, Jour. Sci. (1991).

Ameen, B. M., "Sedimentological Study of Gercus Formation in NE–Iraq", Unpublished. Ms.c. thesis, Unv. Baghdad, 103p. (1998).

Ameen, B. M. "Sequence Stratigraphy of Gercus Formation (Middle Eocene) in Sulaimaniya area, NEIraq", Iraqi Journal of Earth Science, Vol. 6, No. 2, pp. 23-32, (2006). DOI:

Al-Mashaikie, S Z., Al-Azzawi, A T. A and Kadhum A K., "Lithofacies Architecture of the Gercus Formation in Jabal Haibat Sultan, NE Iraq; New Concept of Lithostratigraphy and Depositional Environment", Journal of Environment and Earth Science Vol. 3, No.12. (2013).

Hussain S H. and Aghwan, T. A. "Sedimentology and evolution of a foreland desert basin, Middle Eocene Gercus Formation (North and Northeastern Iraq)", Arabian Journal of Geosciences, Vol. 8, Issue 5, pp. 2799-2830. (2015). DOI:

Jassim, S.Z. and Goff, J.C., "Geology of Iraq. Published by Dolin", Prague and Moravian Museun, Berno, 341p. (2006).

Karim, K. H, Al-Barzinjy, S.T. and Ameen and B. M., "History and Geological Setting of Intermontane Basin in the Zagros Fold-Thrust Belt, Kurdistan Region, NE-Iraq", Iraqi Bulletin of Geology and Mining, Vol.4, No.1, pp.21-33, (2008).

Barzinjy, S. T. M., "Stratigraphy and Basin Analysis of Red Bed Series from Northeastern Iraq, Kurdistan Region". Unpublished Ph.D. thesis, University of Sulaimani, 159p. (2005).

Karim, K. H., "Modification of the time-expanded stratigraphic column of North East Iraq during Cretaceous and Tertiary". Petroleum Geology of Iraq (First Symposium, 21-22april, Baghdad, Abstract book, p4. (2010).

Karim K H, Al- Hakari S HS, Kharajiany S O. A and Khanaqa P A. "Surface analysis and critical review of Darbandikhan (Khanaqin fault), Kurdistan Region, NE-Iraq", Kurdistan Acadimicis Journal (KAJ), Vol. 12, No. 1, pp. 61-75. (2016).

Karim, K.H., "Facies Changes Between Kolosh and Sinjar Formations Along Zagros Fold–Thrust Belt in Iraqi Kurdistan Region". Journal of Geography and Geology. Vol. 8, No. 1. (2016). DOI:

Karim, K.H., Daud, H.S. and Kuradawy, AR, "Record of Khurmala Formation (Late Paleocene-Early Eocene) in the Sulaimani Governorate, Kurdistan Region, Northeast Iraq", accepted for publication in Iraqi Geological Journal (IGJ). (2018). DOI:

Baziany, M. M., "Geology of bedded Gypsum in the Gercus Formation (Early-Middle Eocene) in Dohuk area, Kurdistan Region, Northern Iraq". The Proceedings of third International Conferences on Geo-Resources of the Middle East and North Africa (GRMENA-III), Egypt, Cairo University, Vol.1. (2009).

Karim, K. H., Surdashy A. M. and S. T. Al-Barzinjy, "Concurrent and lateral deposition of flysch and molasses in the foreland basin of Upper Cretaceous and Palaeocene from NE-Iraq, Kurdistan Region", GERMENA II, pp.757-769. (2007).

Martın-Martın, M., Rey, J. Alcala-Garcia F. J., Antoine P.O. "Tectonic controls on the deposits of a foreland basin: An example from the Eocene Corbières-Minervois basin", France, Basin research, Vol.13, pp.419-433. (2001). DOI:

Mountney N. P. and Jagger, A., "Stratigraphic evolution of an aeolian erg margin system: the Permian Cedar Mesa Sandstone, SE Utah, USA", Sedimentology, Vol. 51, pp. 713–743. (2004). DOI:

Saura E, Vergés J, Homke S, Blanc E, Serra-Kiel J, Bernaola G, Casciello E, Fernández N, Romaire I, Casini G, Embry JC, Sharp IR, Hunt DW, "Basin architecture and growth folding of the NW Zagros early foreland basin during the Late Cretaceous and early Tertiary". J. Geol Soc Lond Vol. 168, pp. 235–250. (2011). DOI:

Aswad KJ, Al Samman AHM, Aziz NR, Koyi HA, "The geochronology and petrogenesis of Walash volcanic rocks, Mawat nappes: constrains on the evolution of the northwestern Zagros suture zone", Kurdistan Region, Iraq. Arab J Geosci Vol. 28, pp. 1–30. (2013). DOI:

Rodríguez-López JP, Melendez N, De Boer PL, Soria AR, "Control on marine-erg margin cycle variability: aeolian-marine interaction in the mid-Cretaceous Iberian Desert System, Spain". Sedimentology Vol. 59, pp. 466–501. (2012). DOI:

Buday, T. C, "Regional Geology of Iraq: Vol. 1", Stratigraphy, I. I. M Kassab and S. Z. Jassim (Eds) D. G. Geol. Surv. Min. Invest. Pub. 445p. (1980).

Buday, T. and Jassim, S. Z., "The Regional geology of Iraq: Tectonics, Magmatism and Metamorphism". I.I. Kassab and M.J. Abbas (Eds), Baghdad, 445 p. (1987).

Numan, N. M. S., "A plate tectonic scenario for the Phanerozoic succession in Iraq". Iraqi Geological Journal, Vol.30, No. 2, pp.85-110. (1997).

Numan, N. M. S., "Discussion of “dextral transpression in the Late Cretaceous continental collision, Sanandaj–Sirjan Zone, Western Iraq". Journal of Structural Geology, Vol. 22, No. 8. pp. 1125–1139. University Press, pp.197. (2000). DOI:

Numan, N. M. S. and Al-Azzawi, N.K. "Progressive versus paroxysmal Alpine folding in Sinjar Anticline, North-western Iraq". Iraqi Jour. Earth of Sci., Vol. 2, No.2, pp.59-69. (2002). DOI:

Al-Qayim, B., "Sedimentation and tectonic environment of the Suwais Red Beds", NE-Margin of the Arabian plate-5th international conference on the geology of the Arab world, Egypt. Abstract book, p.112. (2000).

Ghasemi, A., Talbot C.J., "A new tectonic scenario for the Sanandaj–Sirjan Zone (Iran)". Journal of Asian Earth Sciences ,Vol. xx, p. 1–11. (2005).

Chandler F.W. "Quartz arenites: review and interpretation", Sedimentary Geology Vol. 58, No. 2-4, pp. 105-126. (1988). DOI:



How to Cite

New Ideas and Critical review of Middle Eocene Gercus Formation, Kurdistan Region, NE-Iraq. (2018). Journal of Zankoy Sulaimani - Part A, 20(2), 81-94.

Most read articles by the same author(s)

1 2 > >>