Cretaceous Limestone Dolomitization and Argument of Its Mg2+ Sources: Exampling the Bekhme and Qamchuqa Formations in the Zagros Collision Belt

Kamal Haji Karim; Sherzad Tofiq Mohamad

doi:10.24017/science.2024.1.12

Authors

Kamal Haji Karim Department of Geology, University of Sulaimani, Sulaymaniyah, Iraq https://orcid.org/0000-0003-0685-3103
Sherzad Tofiq Mohamad Department of Geology, University of Sulaimani, Sulaymaniyah, Iraq https://orcid.org/0000-0002-8010-1551

Abstract

This study unveils new considerations regarding the dolomitization of the Bekhme and Qamchuqa formations (BQFs), two reefal Cretaceous units in the Iraqi Zagros collisional belt. Previous studies proposed the dolomitization of these formations due to the ascent of Mg-rich hydrothermal solutions through deep faults but lacked substantial supporting evidence. This paper present new considerations suggesting that the dolomitization of the BQFs resulted from the Cretaceous environmental conditions and basin paleogeographic setting of the platform on which these formations were deposited. To justify this consideration, seven proofs presented. First is the occurrence of dolomite as vast layers extending tens of kilometers laterally and bounded between limestone beds, which resemble a strata-bound occurrence. Second is the absence of vertical selective dolomitization such as, hydrothermal mineralization, vertical dolomite dykes, hydrothermal vents, tubes, or zones. Third is the barrenness of most of the fault surfaces and their surrounding rocks with selective dolomitization. Fourth is the sharp boundary between the dolomite and limestone layers, indicating a sudden environmental change from lagoon to reef or forereef. Fifth is the record of dolomitization in the sediments reworked by bioturbation, evident in thalassinoides burrows. Sixth is the succession of BQFs underlain by limestone and green marl devoid of dolomitization and hydrothermal upward movement. Seventh is the contradictory notion of hydrothermal dolomitization among the most recent study published in the Science journal which atributed dolomitization to normal temperate on earth surface. In the present study, the source of the Mg is argued and its presence is attributed to the warmth of the Arabian platform (plate) near the equator during the Cretaceous period. Another source is the connection of the Arabian platform with the Neo-Tethys Sea, which was the locus of Mg-rich mafic volcanism in the form of arcs and mid-oceanic ridge topography, which supplied a voluminous amount of Mg to the Arabian carbonate platform through ocean currents.

Keywords:

Hydrothermal dolomitization, Qamchuqa formation, Bekhme formation, Zagros collisional belt, Zebra dolomite

References

K. H. Karim, R. K. Al-Hamadani, and S. H. Ahmad, “Relations between deep and shallow stratigraphic units of Northern Iraq during Cretaceous,” Int. J. Earth Sci., vol. 4, no. 2, pp. 93-103, 2012. Accessed: June 28, 2024. [Online]. Available: https://sanad.iau.ir/Journal/ijes/Article/917202

K. H. Karim, “New geologic setting of the Bekhme Formation,” J. Zankoy Sulaimani (A), vol. 15, no. 3, pp. 23-38, 2013.

T. Buday, The Regional Geology of Iraq: Stratigraphy and Paleogeography, Geologic Survey, Baghdad, 1980.

B. Al-Qayim, “Diagenetic model of a reef complex, Aqra-Bakhme Formation (Late Cretaceous) northeastern Iraq,” Acta Mineral.-Perogr., vol. 30, no. 1, pp. 149-159, 1989.

K. H. Karim and B. M. Ameen, “New sedimentologic and stratigraphic characteristics of the upper boundary of Qamchuqa Formation (Early Cretaceous) in Northwest of Erbil, Kurdistan Region, NE-Iraq,” Iraqi Geol. Bull., vol. 4, no. 1, pp. 1-13, 2008.

M. S. Nourmohamadi, R. A. Abdula, F. Albeyati, A. O. Sharezwri, E. M. Perot, S. E. Jassim, and N. H. Othman, “Green glauconitic marl bed as a sequence stratigraphical key for interpretation of contact between Qamchuqa and Bekhme formations in Bekhal area, Kurdistan region, NE Iraq,” Bull. Geol. Soc. Malays., vol. 70, no. 1, pp. 29-38, 2020. https://doi.org/10.7186/bg70202003 DOI: https://doi.org/10.7186/bg70202003

H. Mansurbeg, D. Morad, R. Othman, S. Morad, A. Ceriani, I. Al-Aasm, and H. Koyi, “Hydrothermal dolomitization of the Bekhme formation (Upper Cretaceous), Zagros Basin, Kurdistan Region of Iraq: Record of oil migration and deg-radation,” Sediment. Geol., vol. 341, pp. 147-162, July 2016. https://doi.org/10.1016/j.sedgeo.2016.05.015 DOI: https://doi.org/10.1016/j.sedgeo.2016.05.015

K. H. Karim, I. S. Al-Aasm, and H. Mansurbeg, “Structurally-controlled hydrothermal fluid flow in an extensional tectonic regime: A case study of Cretaceous Qamchuqa Formation, Zagros Basin, Kurdistan Iraq,” Sediment. Geol., vol. 386, pp. 52-78, 2019. https://doi.org/10.1016/j.sedgeo.2019.04.001 DOI: https://doi.org/10.1016/j.sedgeo.2019.04.001

H. D. Holland and H. Zimmermann, “The dolomite problem revisited,” Int. Geol. Rev., vol. 42, no. 6, pp. 481-490, 2000. DOI: https://doi.org/10.1080/00206810009465093

R. S. Arvidson and F. T. Mackenzie, “The dolomite problem; control of precipitation kinetics by temperature and sat-uration state,” Am. J. Sci., vol. 299, no. 4, pp. 257–288, 1999. https://doi.org/10.1080/00206810009465093 DOI: https://doi.org/10.2475/ajs.299.4.257

H. G. Machel, “Concepts and models of dolomitization: A critical reappraisal,” Geol. Soc. Lond., Spec. Publ., vol. 235, no. 1, pp. 7–63, 2004. https://doi.org/10.1144/GSL.SP.2004.235.01.02 DOI: https://doi.org/10.1144/GSL.SP.2004.235.01.02

J. Kim, Y. Kimura, B. Puchala, T. Yamazaki, U. Becker, and W. Sun, “Dissolution enables dolomite crystal growth near ambient conditions,” Science, vol. 382, no. 6673, pp. 915-920, 2023. https://doi.org/10.1126/science.adi3690 DOI: https://doi.org/10.1126/science.adi3690

K. H. Karim, P. A. Khanaqa, and K. M. Ismail, “Role of facies changes in shifting trends of anticlines in the Zagros Fold-Thrust belt: Examples from Sulaimani area, Kurdistan Region, northeastern Iraq,” J. Zankoy Sulaimani (A), vol. 22, no. 1, pp. 1-28, 2020. https://doi.org/10.17656/jzs.10770 DOI: https://doi.org/10.17656/jzs.10770

K. H. Karim, “Facies Changes Between Kolosh and Sinjar Formations Along Zagros Fold–Thrust Belt in Iraqi Kurdi-stan Region,” J. Geogr. Geol., vol. 8, no. 1, pp. 1-13, 2016. https://doi.org/10.5539/jgg.v8n1p1 DOI: https://doi.org/10.5539/jgg.v8n1p1

K. H. Karim, and M. Abioui, “Geology of the Zagros basaltic bodies: Examples from the Avroman Mountains, Kurdi-stan Region, Northeast Iraq,” J. Sediment. Environ., vol. 6, no. 2, pp. 169–188, 2021. https://doi.org/10.1007/s43217-020-00045-0 DOI: https://doi.org/10.1007/s43217-020-00045-0

D. Desbruyères et al., “A review of the distribution of hydrothermal vent communities along the northern Mid-Atlantic Ridge: dispersal vs. environmental controls,” Hydrobiologia, vol. 440, pp. 201-216, 2000. https://doi.org/10.1023/A:1004175211848 DOI: https://doi.org/10.1007/978-94-017-1982-7_19

C. Laschet, “On the origin of cherts,” Facies, vol. 10, pp. 257–289, 1984. https://doi.org/10.1007/BF02536693 DOI: https://doi.org/10.1007/BF02536693

A. A. Ghafur, O. S. Hersi, K. V. Sissakian, O. H. Omer, and A. H. Abdulhaq, “Facies-controlled dolomitization of the Lower Cretaceous Qamchuqa Formation, Kurdistan Region, Northern Iraq,” GeoConvention, Calgary, Canada, 2019.

K. H. Karim, “Early Cretaceous calciturbidites facies from Zagros Fold–Thrust belt: A key to paleogeography and en-vironment of northeast Arabian Platform Passive Margin, examples from Kurdistan Region, Northeast Iraq,” Car-bonates Evaporites, vol. 35, no. 19, 2020. https://doi.org/10.1007/s13146-020-00617-1 DOI: https://doi.org/10.1007/s13146-019-00544-w

K. H. Karim, “New geologic setting of the Bekhme Formation, 1st Geological Conference of Kurdistan (Geokurdistan 2012),” J. Zankoy Sulaimani (A), vol. 15, no. 3, pp. 23-38, 2013. DOI: https://doi.org/10.17656/jzs.10257

J. B. Murphy, and R. D. Nance, “How Do Supercontinents Assemble? One theory prefers an accordion model; another has the continents travel the globe to reunite,” Am. Scientist, vol. 92, no. 4, pp. 324-333, 2004. https://www.jstor.org/stable/27858421 DOI: https://doi.org/10.1511/2004.4.324

Z. Lu, and D. Dzurisin, “In SAR imaging of Aleutian volcanoes. In InSAR imaging of Aleutian volcanoes,” in Spring-er, Berlin, Heidelberg, 2014, pp. 87-345. DOI: https://doi.org/10.1007/978-3-642-00348-6_6

W. J. Kious, and R. I. Tilling, “This dynamic Earth-The story of plate tectonics,” U.S. Geol. Surv. Gen. Interest Publ., 1996. https://doi.org/10.3133/7000097 DOI: https://doi.org/10.3133/7000097

C. Breislin et al., “Controls on dolomitization in extensional basins: An example from the Derbyshire Platform, UK,” J. Sediment. Res., vol. 90, no. 9, pp. 1156-1174, 2020. https://doi.org/10.2110/jsr.2020.58 DOI: https://doi.org/10.2110/jsr.2020.58

U. Kelka, M. Veveakis, D. Koehn, and N. Beaudoin, “Zebra rocks: compaction waves create ore deposits,” Sci. Rep., vol. 7, no. 1, pp. 1-9, 2017. https://doi.org/10.1038/s41598-017-14541-3 DOI: https://doi.org/10.1038/s41598-017-14541-3

P. Nielsen, R. Swennen, P. H. Muchez, and E. Keppens, “Origin of Dinantian zebra dolomites south of the Bra-bant-Wales Massif, Belgium,” Sediment., vol. 45, no. 4, pp. 727–743, 1998. https://doi.org/10.1046/j.1365-3091.1998.00171.x DOI: https://doi.org/10.1046/j.1365-3091.1998.00171.x

V. Vandeginste, R. U. D. Y. Swennen, S. A. Gleeson, R. M. Ellam, K. I. R. K. Osadetz, and F. Roure, “Zebra dolomitiza-tion as a result of focused fluid flow in the Rocky Mountains Fold and Thrust Belt, Canada,” Sediment., vol. 52, no. 5, pp. 1067-1095, 2005. https://doi.org/10.1111/j.1365-3091.2005.00724.x DOI: https://doi.org/10.1111/j.1365-3091.2005.00724.x

E. Merino, “Self-accelerating dolomite-for-calcite replacement and displacive zebra veins: Dynamics of burial dolo-mitization,” Geochim. Cosmochim. Acta, vol. 70, no. 18 suppl, pp. A417, 2006. https://doi.org/10.1016/j.gca.2006.06.839 DOI: https://doi.org/10.1016/j.gca.2006.06.839

D. W. Morrow, “Zebra and box work fabrics in hydrothermal dolomites of northern Canada: Indicators for dilational fracturing, dissolution or in situ replacement,” Sediment., vol. 61, no. 4, pp. 915–951, 2014. https://doi.org/10.1111/sed.12094 DOI: https://doi.org/10.1111/sed.12094

R. A. Abdula, “Geothermal gradients in Iraqi Kurdistan deduced from bottom hole temperatures,” Egypt. J. Pet., vol. 26, no. 3, pp. 601-608, 2017. https://doi.org/10.1016/j.ejpe.2016.08.007 DOI: https://doi.org/10.1016/j.ejpe.2016.08.007

I. M. Ghafor, K. H. Karim, and M. M. Baziany, “Age determination and origin of crenulated limestone in the eastern part of Sulaimaniyah Area, Kurdistan Region, NE Iraq,” Iraqi Geol. Bull., vol. 8, no. 2, pp. 21-30, 2012. Accessed: June 28, 2024. [Online]. Available: https://ibgm-iq.org/ibgm/index.php/ibgm/article/view/188

K. H. Karim, “Paleofluid Flow, Fracturing and Reservoir Implications in Foreland basins: an example from the Creta-ceous Qamchuqa Formation, Kurdistan Iraq,” Ph.D. dissertation, Univ. of Windsor, Canada, 2019. https://scholar.uwindsor.ca/etd/7813

K. H. Karim, P. A. Khanaqa, S. O. Kharajiany, Z. A. Taha, and M. M. Baziany, “Depositional and erosional features of Oligocene paleokarsts in the Kirkuk Group, Kurdistan Region, Northeast Iraq,” Arab. J. Geosci., vol. 13, no. 270, 2020. https://doi.org/10.1007/s12517-020-5279-y DOI: https://doi.org/10.1007/s12517-020-5279-y

K. H. Karim, and Z. S. Tahir, “Unconformity and Paleokarst in the Lower Part of the Qamchuqa Formation; An Exam-ple from the Arabian Carbonate Platform in the Zagros Belt NE Iraq,” Iraqi Geol. J., vol. 55, no. 2A, pp. 131-150, 2022. https://doi.org/10.46717/igj.55.2A.9Ms-2022-07-25 DOI: https://doi.org/10.46717/igj.55.2A.9Ms-2022-07-25

A. Chatalov, “Origin of fabric-selective dolomitization recognizable in the field: two case studies from Anisian car-bonate rocks in the western Balkanides,” Geol. Balcanica, vol. 47, no. 1, pp. 43-60, 2018. https://doi.org/10.52321/GeolBalc.47.1.43

W. J. Burgess, “Stratigraphic dolomitization in Arbuckle rocks in Oklahoma,” Tulsa Geol. Soc. Dig., vol. 32, pp. 45-48, 1964. http://ogs.ou.edu/docs/geologynotes/GN-V26N3.pdf

F. N. Al-Sadooni, “Sedimentology and petroleum prospects of the Qamchuqa Group, Northern Iraq,” Ph.D. disserta-tion, Univ. of Bristol, 1978.

S. Al Shdidi, G. Thomas, and J. Delfaud, “Sedimentology, diagenesis, and oil habitat of Lower Cretaceous Qamchuqa Group, northern Iraq,” AAPG Bull., vol. 79, no. 5, pp. 763-778, 1995. https://doi.org/10.1306/8D2B1B9C-171E-11D7-8645000102C1865D DOI: https://doi.org/10.1306/8D2B1B9C-171E-11D7-8645000102C1865D

S. Z. Jassim, and J. C. Goff, Geology of Iraq, Prague: Dolin, 2006, pp. 341.

E. Flügel, Microfacies of Carbonate Rocks: Analysis, Interpretation and Application, Berlin: Springer, 2004. https://doi.org/10.1007/978-3-662-08726-8 DOI: https://doi.org/10.1007/978-3-662-08726-8

B. M. Ameen, “Lithostratigraphy and sedimentology of Qamchuqa Formation from Kurdistan region, NE-Iraq,” Ph.D. dissertation, Univ. of Sulaimani, 2008.

B. M. Ameen, and K. H. Karim, “Depositional environment of Early Cretaceous Arabian Platform: An example from Kurdistan Region, NE-Iraq,” in Proc. 3rd Sci. Conf. Coll. Sci., Univ. of Baghdad, 2009, pp. 1949–1965.

A. Chatalov, “Origin of fabric-selective dolomitization recognizable in the field: two case studies from Anisian car-bonate rocks in the western Balkanides,” Geol. Balcanica, vol. 47, no. 1, pp. 43-60, 2018. https://doi.org/10.52321/GeolBalc.47.1.43 DOI: https://doi.org/10.52321/GeolBalc.47.1.43

W. J. Burgess, “Stratigraphic dolomitization in Arbuckle rocks in Oklahoma,” Tulsa Geol. Soc. Dig., vol. 32, pp. 45-48, 1964.

H. K. Karim, and I. M. Ghafur, “Updated stratigraphy, tectonics and boundary conditions of the Mawat and Bulfat Ophiolite Complexes, Kurdistan Region, NE-Iraq,” in Proc. 2nd Int. & 4th Sci. Conf. Coll. Sci. Univ. Tikrit, 2020, pp. 127-149.

D. A. Latif, Y. O. Mohammad, and M. M. Baziani, “Mineralogy and Origin of manganese deposit in the Sulaimani Province, Kurdistan Region of Iraq: Insight to Serpentinization-Induced manganese production Scenario,” Iraqi Geol. J., vol. 55, pp. 178-200, 2022. https://doi.org/10.46717/igj.55.1F.15Ms-2022-06-30 DOI: https://doi.org/10.46717/igj.55.1F.15Ms-2022-06-30

A. A. Aqrawi, J. C. Goff, A. D. Horbury, and F. N. Sadooni, The petroleum geology of Iraq, Beaconsfield: Scientific Press, 2010.