Sedimentary paleoenvironments, paleoecology and transgressive-regressive sequence stratigraphy of the Eocene–Oligocene rocks in northern Bahariya Depression, Egypt
DOI:
https://doi.org/10.32523/59fsh138Keywords:
Depositional environments, Paleoecology, Diagenesis, Sequence stratigraphy, Eocene, Oligocene, Bahariya DepressionAbstract
This study describes the depositional facies, paleoecological, sequence, and diagenetic features of the Eocene–Oligocene succession exposed in northern Bahariya Depression, Western Desert, Egypt. This Eocene–Oligocene succession is composed of five stratigraphic units, from base to top, the Naqb (early Eocene), Qazzun (middle Eocene), and El-Hamra (middle-late Eocene) formations, followed by the Radwan (early Oligocene) and El-Ris (late Oligocene-Miocene?) formations. Several miscellaneous larger benthic foraminiferal and macrofaunal assemblages were identified from the studied Eocene rock units and interpreted ecologically. Analyses of litho-, bio-, and microfacies resulted in the recognition six major facies associations that record a range from peritidal flats to restricted and outer lagoons, and reefal environments of the Eocene rocks, to fluvial and shallow lacustrine terresteiral environments of the Oligocene rocks. The most common diagenetic features recorded in the examined rocks likely resulted from cementation, dolomitization, silicification, glauconitization, and iron replacement.
The studied Eocene–Oligocene succession is comprised of two major systems tracts, a transgressive systems tract at the bottom, followed upward by a regressive systems tract. The change of depositional trend from a transgressive to a regressive mode was essentially developed in response to the progressive decrease in accommodation space and the increase of sediment supply.
Downloads
References
1. Adams, J.E., and Rhodes, M.L. (1960). Dolomitization by seepage refluxion. Bull. Am. Ass. Petrol. Geol., 44, 1912-1920. DOI: https://doi.org/10.1306/0BDA6263-16BD-11D7-8645000102C1865D
2. Afify, A.M., Serra Kiel, J., Sanz-Montero, M.E., Calvo, J.P., and Sallam, E.S. (2016). Nummulite biostratigraphy of the Eocene succession in the Bahariya Depression, Egypt: implications for timing of iron mineralization. Journal of African Earth Sciences, 120, 44-55. http://dx.doi.org/10.1016/j.jafrearsci.2016.04.016 DOI: https://doi.org/10.1016/j.jafrearsci.2016.04.016
3. Al-Dhwadi, Z., and Sallam, E.S. (2019). Spheroidal “Cannonballs” calcite‑cemented concretions from the Faiyum Bahariya depressions, Egypt: evidence of differential erosion by s storms. Internatioal Journal of Earth Sciences, 108, 2291–2293. https://doi.org/10.1007/s00531-019-01753-3 DOI: https://doi.org/10.1007/s00531-019-01753-3
4. Amorosi, A. (1995). Glaucony sequence stratigraphy: A conceptual framework of distribution in siliciclastic sequences. J. Sediment. Res., 65, 419–425. DOI: https://doi.org/10.1306/D4268275-2B26-11D7-8648000102C1865D
5. Assal, E.M., Wanas, H.A., and Abou Awad, H.A. (2024). The Middle-Upper Eocene in the Northern Plateau of the Bahariya Depression, Western Desert (Egypt) correlation with other Tethyan sectors. Marine Petroleum Geology, 161, 106705. DOI: https://doi.org/10.1016/j.marpetgeo.2024.106705
6. Attia, M.I. (1950). The geology of the iron-ore deposits of Egypt. Geological Survey of Egypt, paper 7, p. 34.
7. Ayoub, N.A., Ahmed, S.M., Osman, R.A., Hassan, M.S., Sallam, E.S., 2025a. Facies evolution of the Eocene-Oligocene succession in Northern Bahariya Depression (Western Desert, Egypt): depositional controls, palaeoenvironments, palaeobiogeography. Journal of Sedimentary Environments. https://doi.org/10.1007/s43217-025-00263-4 DOI: https://doi.org/10.1007/s43217-025-00263-4
8. Ayoub, N.A., Ahmed, S.M., Osman, R.A., Hassan, M.S., Sallam, E.S., 2025b. Palaeoenvironments palaeobiogeographical distribution of the Eocene larger benthic foraminifera macrofaunal associations in the northern plateau of the Bahariya Depression, Western Desert, Egypt. Benha Journal of Applied Sciences,10 (2), 91-109. DOI: https://doi.org/10.21608/bjas.2025.371594.1656
9. Baioumy, H.M., and Hassan, M.S. (2004). Authigenic halloysite from El Gedida iron ores, Bahariya Oasis, Egypt: characterization origin. Clay Minerals. 39, 207–217. DOI: https://doi.org/10.1180/0009855043920131
10. Baioumy, H.M., Mohamed Z. Khedr, M.Z., and Ahmed, A.H. (2013). Mineralogy, geochemistry origin of Mn in the high-Mn iron ores, Bahariya Oasis, Egypt. Ore Geology Reviews, 53, 63–76. DOI: https://doi.org/10.1016/j.oregeorev.2012.12.009
11. Ball, J., and Beadnell, H.J.L. (1903). Bahariya Oasis: its topography geology. Egypt Surv. Dept., 84 pp.
12. Basta, E., and Amer, H. (1969). El Gedida iron ores their origin, Bahariya Oases, Egypt. Economic Geology, 64, 424–444. DOI: https://doi.org/10.2113/gsecongeo.64.4.424
13. Bell, D.L., and Goodell, H.G. (1967). A comprehensive study of glauconite the associated clay fraction in modern marine sediments. Sedimentology, 9, 169-202. DOI: https://doi.org/10.1111/j.1365-3091.1967.tb02038.x
14. Blatt, H., Middleton, G.V., and Murray, R.C. (1980). Origin of Sedimentary Rocks. Prentica-Hall, New Jersey, 634 pp.
15. Boukhary, M., Hussein-Kamel, Y., Abdelmalik, W., and Besada, M. (2011). Ypresian nummulites from the Nile Valley the Western Desert of Egypt: their systematic biostratigraphic significance. Micropaleontology, 571, 1-35. DOI: https://doi.org/10.47894/mpal.57.1.01
16. Catuneanu, O. (2006). Principles of Sequence Stratigraphy. Elsevier (Amsterdam), 386 pp.
17. Catuneanu, O., Khalifa, M.A., and Wanas, H.A. (2006). Sequence stratigraphy of the Lower Cenomanian Bahariya Formation, Bahariya Oasis, Western Desert, Egypt. Sedimentary Geology, 190, 121–137. DOI: https://doi.org/10.1016/j.sedgeo.2006.05.010
18. Catuneanu, O., Galloway,W.E., Kendall, Ch. G. St. C., Miall, A.D., Posamentier, H.W., Strasser, A., and Tucker, M.T. (2011). "Sequence stratigraphy: Methodology Nomenclature", Newsletters on Stratigraphy, Stuttgart, 44/3, 173–245. DOI: https://doi.org/10.1127/0078-0421/2011/0011
19. Cloud, P.E. (1955). Physical limits of glauconite formation. AAPG Bulletin, 39, 484-492. DOI: https://doi.org/10.1306/5CEAE166-16BB-11D7-8645000102C1865D
20. Dabous, A.A. (2002). Uranium isotopic evidence for the origin of the Bahariya iron deposits, Egypt. Ore Geology Reviews, 19, 165–186. DOI: https://doi.org/10.1016/S0169-1368(01)00039-7
21. Dickson, J.A.D. (1965). A modified staining technique for carbonates in thin section. Nature, 205: 587. DOI: https://doi.org/10.1038/205587a0
22. Duff, P.McL.D., Hallam, A., and Walton, E.K. (1967). Cyclic sedimentation. Elsevier, Amsterdam, 280pp.
23. Dunham, R.J. (1962). Classification of carbonate rocks according to depositional texture. In: Ham, W.E. (Ed.) Classification of carbonate rocks. Tulsa, Okla. A.A.P.G. Memoirs, 1, 108–121. DOI: https://doi.org/10.1306/M1357
24. El Akkad, S., and Issawi, B. (1963). Geology iron ore deposits of the Bahariya Oasis: Geological Survey Mineral Research Department, Egypt, Paper 18, 301 p.
25. El Aref, M.M., and Lotfy, Z.H. (1985). Genetic karst significance of the iron ore deposits of El Bahariya Oasis, Western Desert, Egypt. Annals Geological Survey of Egypt, 15, 1–30.
26. El Aref, M.M., Mesaed, A.A., Khalil, M.A., and Salama, W.S. (2006). Stratigraphic setting, facies analyses depositional environments of the Eocene ironstones of Gabal Ghorabi mine area, El Bahariya Depression, Western Desert, Egypt. Egyptian Journal of Geology, 50, 29–57.
27. El Bassyony, A.A. (1980). The discovery of El Gedida iron ores their origin, Bahariya Oases, Western Desert, Egypt. Journal of the Geological Society of Iraq, 13, 119-130.
28. El Habaak, G., Askalany, M., Galal, M., and Abdel-Hakeem, M. (2016). Upper Eocene glauconites from the Bahariya Depression: An evidence for the marine regression in Egypt. Journal of African Earth Sciences, 117, 1-11. DOI: https://doi.org/10.1016/j.jafrearsci.2016.01.013
29. El Sharkawi, M.A., Higazi, M.M., and Khalil, N.A. (1984). Three genetic iron ore dikes of iron ores at El Gedida mine, Western Desert, Egypt. Geological Society of Egypt, 21st Annual Meeting, Cairo, Egypt, p. 68.
30. El Shazly, E.M. (1962). Report on the results of drilling in the iron ore deposit of Gebel Ghorabi, Bahariya Oasis, Western Desert. Egypt Geol. Surv., 17, 1–25.
31. Embry, A., and Johannessen, E. (1992). T-R sequence stratigraphy, facies analysis reservoir distribution in the uppermost Triassic-Lower Jurassic succession, western Sverdrup Basin, Arctic Canada: in T. Vorren et al., eds., Arctic Geology Petroleum Potential: Norwegian Petroleum Society Special Publication 2, p.121-146. DOI: https://doi.org/10.1016/B978-0-444-88943-0.50013-7
32. Eugster, H.P. (1969). Inorganic bedded cherts from the Magadi area, Kenya. Contr. Mineral. Petrol., 22, 1-31. DOI: https://doi.org/10.1007/BF00388011
33. Fischer, A.G., Honjo, S., and Garrison, R.E. (1967). Electron micrographs of limestones their nannofossils. Princeton Monogr. Geol. Paleont., No. 1, 141 p. DOI: https://doi.org/10.1515/9781400885923
34. Flügel, E. (2004). Microfacies of carbonate rocks: Analysis, Interpretation Application. Springer Berlin Heidelber, New York, 976 pp.
35. Flügel, E. (2010). Microfacies of Carbonate Rocks: Analysis, Interpretation Application. Springer Verlag, New York, 996 pp. DOI: https://doi.org/10.1007/978-3-642-03796-2
36. Folk, R.L. (1962). Spectral subdivision of limestone types, In: Ham, W.E. (Ed.) Classification of carbonate rocks - a symposium. AAPG. Mem. No. 1, 62-84.
37. Folk, R.L. (1974). The nature of crystalline calcium carbonate, effect of magnesium content salinity. Journal of Sedimentary Petrology, 44, 40-53. DOI: https://doi.org/10.1306/74D72973-2B21-11D7-8648000102C1865D
38. Friedman, G.M., and Sers, J.E. (1978). Principles of Sedimentology. John Wiley, New York, 792pp.
39. Gheith, M.A. (1955). Classification Review of Iron Ore Deposits. Symposium of Applied Geology of Near East. UNESCO, Ankara, 106–113.
40. Haq, B.U., and Ogg., J.G. (2024). Retraversing the highs lows of Cenozoic sea levels: GSA Today, https://doi.org/10.1130/GSATG593A.1. DOI: https://doi.org/10.1130/GSATGG593A.1
41. Heckel, P.H. (1972). Recognition of ancient shallow marine evironments. In: Recognition of Ancient Sedimentary Environments by Rigby, J.K. and Hamblin, W.K. (Eds.), Spec. Publ. Soc. econ. Paleont. Miner., Tulsa, 16, pp. 226-296. DOI: https://doi.org/10.2110/pec.72.02.0226
42. Heckel, P.H. (1974). Carbonate buildups in the geologic record: a review. In: Reefs in Time Space by Laporte, L.F. (Ed.), Spec. Publ. Soc. econ. Paleont. Miner., 18, Tulsa, pp. 90-154. DOI: https://doi.org/10.2110/pec.74.18.0090
43. Keheila, E.A., and El-Ayyat, A.M. (1990). Lower Eocene carbonate facies, environments sedimentary cycles in Upper Egypt: evidence for global sea-level changes. Palaeogeography Palaeoclimatology Palaeoecology, 81: 333–347 DOI: https://doi.org/10.1016/0031-0182(90)90038-9
44. Keheila, E.A., and El-Ayyat, A.M. (1992). Silicification dolomitization of the Lower Eocene carbonates in the Eastern Desert between Sohag Qena, Egypt. Journal of African Earth Sciences, 14: 341–349. DOI: https://doi.org/10.1016/0899-5362(92)90037-D
45. Khalifa, M.A., and Mashaal, N.M. (2023). Facies framework depositional setting of the Middle‑Upper Eocene Hamra Formation, north of Bahariya Oasis, Western Desert, Egypt. Arabian Journal of Geosciences, 16: 207. DOI: https://doi.org/10.1007/s12517-023-11389-y
46. Knauth, L. P. (1979). A model for the origin of chert in limestone. Geology, 7(6), 274-277. DOI: https://doi.org/10.1130/0091-7613(1979)7<274:AMFTOO>2.0.CO;2
47. Laschet, C. (1984). On the origin of cherts. Facies, 10, 257-289. DOI: https://doi.org/10.1007/BF02536693
48. Longman, M.W. (1977). Factors controlling the formation of microspar in the Bromide Formation. Journal of Sedimentarty Petrology, 47, 347-350. DOI: https://doi.org/10.1306/212F716C-2B24-11D7-8648000102C1865D
49. MacRae, S.G. (1972). Glauconite. Earth-Science Reviews, 8, 397-440. DOI: https://doi.org/10.1016/0012-8252(72)90063-3
50. McBride, E.F. (1989). Quartz cement in sstones: A review. Earth-Science Reviews, 26, 69-112. DOI: https://doi.org/10.1016/0012-8252(89)90019-6
51. Mesaed, A.A., and Suror, A.A. (1999). Mineralogy geochemistry of the Bartonian stratabound diagenetic lateritic glauconitic ironstones of El-Gideda mine, Bahariya Oasis, Egypt. 2nd International Conference on the Geology of the Arab World, Cairo Univ., Egypt, 1, 509-540.
52. Mesaed, A.A., and Suror, A.A. (2000). Mineral chemistry mechanism of formation of the Bartonian glaucony of El Gedida mine, El Bahariya Oasis, Egypt. Egyptian Mineralogist 12, 1-28.
53. Moustafa, A.R., Saoudi, A., Moubasher, A., Ibrahim, I.M., Molokhia, H., and Schwartz, B. (2003). Structural setting tectonic evolution of the Bahariya Depression, Western Desert, Egypt. GeoArabia 8 (1), 91-124. DOI: https://doi.org/10.2113/geoarabia080191
54. Nakhla, F.M. (1961). The iron ore deposits of El-Bahariya Oasis, Egypt. Economic Geology, 56, 1103–1111. DOI: https://doi.org/10.2113/gsecongeo.56.6.1103
55. Odin, G.S., and Fullagar, P.D. (1988). Geological Significance of the Glaucony Facies. In Green Marine Clays: Oolitic Ironstone Facies, Verdine Facies, Glaucony Facies Celadonite-Bearing Rock Facies—A Comparative Study. Developments in Sedimentology, 45, 295–332. DOI: https://doi.org/10.1016/S0070-4571(08)70069-4
56. Odin, G.S., Matter, A. (1981). De glauconiarum origine. Sedimentology, 28, 611–641. DOI: https://doi.org/10.1111/j.1365-3091.1981.tb01925.x
57. Peterson, M.N.A., and von der Borch, C.C. (1965). Chert: modern inorganic deposition in a carbonate-precipitating locality. Science, 149, 1501-1503. DOI: https://doi.org/10.1126/science.149.3691.1501
58. Pettijhon, F.J., Potter, P.E., and Siever, R. (1973). Sand and Sandstone. Springer-Verlag New York, Heidelberg, Berlin, 618 pp. DOI: https://doi.org/10.1007/978-1-4615-9974-6
59. Plyusnina, E.E., Sallam, E.S., and Ruban, D.A. (2016). Geological heritage of the Bahariya Farafra oases, the central Western Desert, Egypt. Journal of African Earth Sciences, 116, 151-159. DOI: https://doi.org/10.1016/j.jafrearsci.2016.01.002
60. Pryor, W.A. (1975). Biogenic sedimentation alteration of argillaceous sediments in shallow marine environments. Bulletin Geological Society of America, 86, 1244–1254. DOI: https://doi.org/10.1130/0016-7606(1975)86<1244:BSAAOA>2.0.CO;2
61. Said, R. (1962). The geology of Egypt. Elsevier Publ. Co. Amesterdam New York, 377p.
62. Said, R. and Issawi, B. (1964). Geology of northern plateau, Bahariya oasis, Egypt. Geological Survey of Egypt, Paper 29, 41 pp.
63. Salama, W., El Aref, M.M., and Gaupp, R. (2015). Spectroscopic characterization of iron ores formed in different geological environments using FTIR, XPS, Mössbauer spectroscopy thermoanalyses. Spectrochimica Acta Part A: Molecular Biomolecular Spectroscopy, 136, 1816–1826. DOI: https://doi.org/10.1016/j.saa.2014.10.090
64. Sallam, E.S., and Ruban, D.A. (2019). Ancient tufa semi-detached megaclasts from Egypt: evidence for sedimentary rock classification development. Internatioal Journal of Earth Sciences, 108 (5): 1615–1616. DOI: https://doi.org/10.1007/s00531-019-01702-0
65. Sallam, E.S., Issawi, B., and Osman, R. (2015a). Stratigraphy, facies, depositional environments of the Paleogene sediments in Cairo-Suez district, Egypt. Arabian Journal of Geosciences, 8 (4), 1939–1964. DOI: https://doi.org/10.1007/s12517-014-1360-8
66. Sallam, E.S., Wanas, H.A., and Osman, R. (2015b). Stratigraphy, facies analysis sequence stratigraphy of the Eocene succession in the Shabrawet area (north Eastern Desert, Egypt): An example for a tectonically influenced inner ramp carbonate platform. Arabian Journal of Geosciences 8 (12), 10433-10458. DOI: https://doi.org/10.1007/s12517-015-1969-2
67. Sallam, E.S., Ruban, D.A., and Van Loon, A.J. (2022). Lagoonal carbonate deposition preceding rifting-related uplift: evidence from the Bartonian–Priabonian (Eocene) in the northwestern Gulf of Suez (Egypt). Journal of Palaeogeography, 11 (1), 8-30 (00254). DOI: https://doi.org/10.1016/j.jop.2021.12.002
68. Sallam, E.S., Erdem, N.Ö., Sinanoğlu, D., and Ruban, D.A. (2018). Mid-Eocene (Bartonian) larger benthic foraminifera from southeastern Turkey northeastern Egypt: New evidence for the palaeobiogeography of the Tethyan carbonate platforms. Journal of African Earth Sciences, 141, 70-85. DOI: https://doi.org/10.1016/j.jafrearsci.2018.01.009
69. Serra-Kiel, J., Hottinger, L., Caus, E., Drobne, K., Ferrandez, C., Jauhri, A.K., Less, G., Pavlovec, R., Pignatti, J., Samso, J.M., Schaub, H., Sirel, E., Strougo, A., Tambareau, Y., Tosquella, J., and Zakrevskaya, E. (1998). Larger foraminiferal biostratigraphy of the Tethyan Paleocene and Eocene. Bull. Soci. Geol. Fr. 169 (2), 281-299.
70. Sinanoğlu, D., Erdem, N.Ö., and Sallam, E.S. (2018). Bartonian benthic foraminifera: Examples from the Arabian North African carbonate platforms. 20th EGU General Assembly, EGU2018, Proceedings from the conference held 4-13 April, 2018 in Vienna, Austria, p.6500. 2018EGUGA..20.6500S.
71. Tanner, L.H., and Khalifa, M.A. (2010). Origin of ferricretes in fluvial-marine deposits of the Lower Cenomanian Bahariya Formation, Bahariya Oasis, Western Desert, Egypt. Journal of African Earth Sciences, 56, 179-189. DOI: https://doi.org/10.1016/j.jafrearsci.2009.07.004
72. Tosson, S., and Saad, N.A. (1974). Genetic studies of El-Bahariya iron ore deposits, Western Desert, Egypt. Neues Jb. Miner. Abh. 121, 317–393.
73. Tucker, M.E. (1981). Sedimentary Petrology: An Introduction. Blackwell Scientific Publications. 2nd edition, Oxford, London, Geoscience texts, v. 3, 252pp.
74. Tucker, M.E., and Wright, V.P. (1990). Carbonate Sedimentology. Blackwell Science, Oxford, 482pp. DOI: https://doi.org/10.1002/9781444314175
75. Walker, R.G. (1979). Facies models. Geoscience Canada, 211pp.
76. Wanas, H.A., Armenteros, I., Recio, C., Sallam, E.S., and Nieto, C.E. (2023). Distal fluvial to lacustrine/palustrine carbonate facies of the El-Ris Formation (Late Miocene?) at the Bahariya Depression, Western Desert, Egypt: Depositional model controls. Journal of African Earth Sciences, 205, 104993. DOI: https://doi.org/10.1016/j.jafrearsci.2023.104993
77. Waugh, B. (1970). Petrology, provenance silica diagenesis of the Penrith Sstone (Lower Permian) of northwest Engl. Journal of Sedimentary Petrology, 40, 1226-1240. DOI: https://doi.org/10.1306/74D72171-2B21-11D7-8648000102C1865D
78. Wilson, J.L. (1975). Carbonate Facies in Geologic History. New York (Springer), 471 pp. DOI: https://doi.org/10.1007/978-1-4612-6383-8
79. Zachos, J.C., Quinn, T.M., and Salamy, K.A. (1996). High-resolution (104 yr) deep-sea foraminiferal stable isotope records of the Eocene-Oligocene climate transition. Paleoceanography, 11, 251–266. DOI: https://doi.org/10.1029/96PA00571
80. Zobaa, M.K., Sallam, E.S., and Oboh-Ikuenobe, F.E. (2015). Palynological evidence for epicontinental dry subtropical to temperate climatic conditions during the Eocene in the southeast Mediterranean. Geological Society of America, Abstracts and Program, 47(7): 142.
Downloads
Published
Issue
Section
License
Copyright (c) 2025 Nada Ayoub, Sayed Ahmed, Rifaat Osman, Mervat Hassan, Emad Sallam (Автор)
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
