Carbonates and Evaporites

, Volume 19, Issue 2, pp 151–161 | Cite as

Dolomitization of Middle Eocene carbonate rocks, Abu Roash area, Egypt

  • A. S. Mansour
  • H. M. Holail


Dolomitization is the most striking diagenetic process affecting the late Middle Eocene shelly limestone beds at Abu Roash and its neighboring areas. Petrographic investigations reveal that these rocks represent shelly-wackstone to packstone microfacies, that they were deposited probably within a shallow subtidal setting. The rock matrix has been subjected to both selective and complete dolomitization and replaced by equigranular mosaics of fine-to medium-grained dolomite (crystalline planar-s dolomite texture). Meanwhile, the embedded shell fragments show high resistance to dolomitization and their original calcite composition is mostly preserved. The petrographic features of the dolomite texture suggest that these dolomites were formed under near surface and low temperature conditions.

Oxygen and carbon isotopic values of the calcite framework grains (−3.8 to −2.0‰ and +1.9 to +2.5‰ PDB, respectively) reflect marine values with some degree of alteration by the effect of slightly18O-depleted diagenetic water. Meanwhile, oxygen and carbon isotopic signatures of the studied dolomites (+0.1 to +1.5‰ and +1.7 to +2.3‰ PDB, respectively) are heavier relative to those of marine limestones. The isotopic signature of dolomites combined with petrographic data is in accord with their formation from modified-marine fluids during early diagenesis.


Dolomite Eocene Microfacies Dolomitization Middle Eocene 
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  1. AIGNER, T., 1983, Facies and origin of nummulitic buildups: an example from the Giza Pyramids Plateau (Middle Eocene, Egypt):Neues Jahrbuch Für Geologie und Paleontologie, v. 166, p. 347–368.Google Scholar
  2. AIGNER, T., 1985, Biofabrics as dynamic indicators in Nummulite accumulations:Journal of Sedimentary Petrology, v. 55, p. 131–134.Google Scholar
  3. AMTHOR, J.E. and FRIEDMAN, G.M., 1992, Early- to late-diagenetic dolomitization of platform carbonates: Lower Ordovician Ellenburger Group, Permian basin, west Texas:Journal of Sedimentary Petrology, v. 62, p. 131–144.Google Scholar
  4. BUDD, D.A., 1992, Dissolution of high-Mg calcite fossils and the formation of biomolds during mineralogical stabilization:Carbonates and Evaporites, v. 7, p. 74–81.Google Scholar
  5. BULLEN, S.B. and SIBLEY, D.F., 1984, Dolomite selectivity and mimic replacement:Geology, v. 12, p. 655–658.Google Scholar
  6. CONIGLIO, M., JAMES, N.P., and AISSAOUI, D.M., 1988, Dolomitization of Miocene carbonates, Gulf of Suez, Egypt:Journal of Sedimentary Petrology, v. 58, p. 100–119.Google Scholar
  7. CONSTANTZ, B.R., 1986, The primary surface area of corals and variations in their susceptibilility to diagenesis, p. 53–76in J.H. Schroeder and B.H. Purser, eds., Reef Diagenesis. Springer Verlag Publishing Company.Google Scholar
  8. ENOS, P., 1983, Shelf Environment,in P.A. Scholle, D.G. Bebout, and C.H. Moore, eds., Carbonate depositional environments. AAPG Memoirs, no. 33, p. 267–296.Google Scholar
  9. FARIS, M.I., 1948, Contribution to the stratigraphy of Abu Rauwash and the history of the Upper Cretaceous in Egypt:Bulletin of Faculty of Science, Cairo University, v. 27, p. 221–239.Google Scholar
  10. FARIS, M.I. and SOLIMAN, S.M., 1961, Petrology of the dolomite rocks of Abu Roash and its consideration to possible petroleum reservoirs in the other parts of Egypt. Third Petroleum Congress, Alexandria, Egypt, 30 p.Google Scholar
  11. FRIEDMAN, G.M., 1980, Dolomite is an evaporite mineral: evidence from the rock record and from sea-marginal ponds of the Red Sea,in D.H. Zenger, J.B. Dunham, and R.L. Ethington, eds., Concepts and models of dolomitization: SEPM Special Publication, v. 28, p. 69–80.Google Scholar
  12. FRIEDMAN, G.M. 1995, Diverse origin of modern dolomite in the Levant:Carbonates and Evaporites, v. 41, p. 65–78.Google Scholar
  13. GHORAB, M.A. and ISMAIL, M.M., 1970, Microfacies of the Abu Roash surface sections:Bulletin of Faculty of Science, Alexandria University, v. 9, p. 331–363.Google Scholar
  14. GIVEN, R.K. and WILKINSON, B.H., 1987, Dolomite abundance and stratigraphic age, constraints on rates and mechanism of Phanerozoic dolostone formation:Journal of Sedimentary Petrology, v. 57, p. 1068–1078.Google Scholar
  15. GREGG, J.M. and SIBLEY, D.F., 1984, Epigenetic dolomitization and the origin of xenotopic dolomite texture:Journal of Sedimentary Petrology, v. 54, p. 908–931.Google Scholar
  16. GREGG, J.M. and SHELTON, K. L. 1990, Dolomitization and dolomite neomorphism in the back reef facies of the Bonneterre and Davis Formations (Cambrian), southeastern Missouri:Journal of Sedimentary Petrology, v. 60, p. 549–562.Google Scholar
  17. HAQ, B.U., HARDENBOL, J., and VAIL, P.R., 1987, Chronology of fluctuating sea levels since the Triassic:Science, v. 235, p. 1156–1167.Google Scholar
  18. HARDIE, L.A. 1987, Dolomitization: a critical view of some current views:Journal of Sedimentary Petrology, v. 57, p. 166–183.Google Scholar
  19. HOLAIL, H.M., 1994a, Diagenesis of the Middle Eocene ‘Nummulitic bank” of the Giza Pyramids Plateau, Egypt: Petrographic and18O/16O evidence:Qatar University Science Journal, v. 14, p. 146–152.Google Scholar
  20. HOLAIL, H.M., 1994b, Carbon and oxygen ratios of Middle Eocene dolomite, Gebel Ataqa, Egypt:Neues Jahrbuch Für Geologie und Paleontologie, Abh, v. 191, p. 111–124.Google Scholar
  21. HOLAIL, H.M., 1998, Radiaxial fibrous calcite cement of Middle Eocene limestones, Giza Pyramids Plateau, Egypt: Isotopic composition and implication to its origin:Journal of Sedimentology of Egypt, v. 6, p. 71–80.Google Scholar
  22. HUDSON, J.D. and ANDERSON, T.F., 1989, Ocean temperatures and isotopic compositions through time:Royal Society of Edinburgh Transactions, Earth Sciences, v. 80, p. 183–192.Google Scholar
  23. HUMPHREY, J.D. and QUINN, T.M., 1989, Coastal mixing zone dolomite, forward modelying, and massive dolomitization of platform-margin carbonates:Journal of Sedimentary Petrology, v. 59, p. 438–454.Google Scholar
  24. JAMES, N.P. and CHOQUETTE, P.W., 1984, “Diagenesis 9: Limestones — The Meteoric Diagenetic Environment”:Geoscience Canada, v. 11, p. 161–194.Google Scholar
  25. LAND, L.S., 1973, Holocene meteoric dolomitization of Pleistocene limestones, north Jamaica:Sedimentology, v. 20, p. 411–424.Google Scholar
  26. LAND, S.L., 1980, The isotopic and trace element geochemistry of dolomite: the state of the art, in D.H. Zenger, J.B. Dunham, and R.L. Ethington, eds., Concepts and models of dolomitization: SEPM Special Publication, v. 28, p. 87–110Google Scholar
  27. LAND, S.L., 1985, The origin of massive dolomite:Journal of Geological Education, v. 33, p. 112–125.Google Scholar
  28. LAND, L.S., 1989, The carbon and oxygen isotopic composition of surficial Holocene shallow marine carbonate sediment and Quaternary limestone and dolomite, p. 191–217in P. Fritz and J. Ch. Fontes, eds., Handbook of Environmental Isotope Geochemistry. Elsevier Publishing Company.Google Scholar
  29. LAND, S.L., 1991, Dolomitization of the Hope Gate Formation, North Jamaica, by seawater: reassessment of mixing-zone dolomite,in H.P. Taylor, J.R. O’Neil, and I.R. Kaplan, eds., Stable Isotope Geochemistry. A Tribute to Samuel Epstein: The Geochemical Society Special Publication, v. 3, p. 121–133Google Scholar
  30. LAND, S.L., Salem, R. and Morrow, D., 1975, Paleohydrology of ancient dolomites: Geochemical evidence.AAPG Bulletin, v. 59, p. 1602–1625.Google Scholar
  31. LOHMANN, K.C. and WALKER, J.C.G., 1989, The record of Phanerozoic abiotic marine calcite cements:Geophysical Research Letters, v. 16, p. 319–322.Google Scholar
  32. LONGMAN, M.W., 1980, Carbonate diagenetic textures from near-surface diagenetic environments:AAPG Bulletin, v. 64, p. 461–487.Google Scholar
  33. MACHEL, H.G. and MOUNTJOY, E.W., 1986, Chemistry and environments of dolomitization — A reappraisal:Earth Science Reviews, v. 23, p. 175–222.Google Scholar
  34. MACHEL, H.G. and MOUNTJOY, E.W., 1990, Coastal mixing zone dolomite, forward modeling, and massive dolomitization of platform-margin carbonates: Discussion:Journal of Sedimentary Petrology, v. 60, p. 1008–1012.Google Scholar
  35. MACHEL, H.G. and BURTON, E.A., 1994, Golden Grove dolomite, Barbados: origin from modified seawater:Journal of Sedimentary Research, v. A64, p. 741–751.Google Scholar
  36. MCKENZIE, J.A., 1981, Holocene dolomitization of calcium carbonate sediments from the coastal sabkhas of Abu Dhabi, U.A.E.: a stable isotope study:Journal of Geology, v. 89, p. 185–198.Google Scholar
  37. MORRISON, J.O. and BRAND, U., 1986, Paleoscene, 5. Geochemistry of Recent marine invertebrates:Geoscience Canada, v. 13, p. 237–254.Google Scholar
  38. MORRISON, J.O. and BRAND, U., 1988, An evaluation of diagenesis and chemostratigraphy of Upper Cretaceous molluscs from the Canadian Interior Seaway:Chemical Geology (Isotope Geoscience Section), v. 72, p. 235–248.Google Scholar
  39. MORROW, D.W., 1982, Diagenesis 1. Dolomite — Part 1: The Chemistry of dolomitization and dolomite precipitation:Geoscience Canada, v. 9, p. 5–13.Google Scholar
  40. MOUSTAFA, A.R., 1988, Wrench tectonics in the north Western Desert of Egypt (Abu Roash area, southwest of Cairo). Middle East Research Center, Ain Shams University, Egypt, v. 2, p. 1–16.Google Scholar
  41. RANDAZZO, A.F. and COOK, D.J., 1987, Characterization of dolomitic rocks from the coastal mixing zone of the Floridan aquifer, Florida, U.S.A.:Sedimentary Geology, v. 54, p. 169–192.Google Scholar
  42. SAID, R., 1962, The geology of Egypt: Elsevier Publishing Company, Amsterdam, 377 p.Google Scholar
  43. SAID, R. and MARTIN, L., 1964, Cairo area, geological excursion notes. Petroleum Exploration Society of Libya, Manual 6th field Conference, p. 107–121.Google Scholar
  44. SALEM, R., 1976, Evolution of Eocene-Miocene sedimentation patterns in Northern Egypt:AAPG Bulletin, v. 60, p. 34–64.Google Scholar
  45. SALLER, A.H., 1984, Petrologic and geochemical constraints on the origin of subsurface dolomite, Enewetak Atoll: An example of dolomitization by normal seawater:Geology, v. 12, p. 217–220.Google Scholar
  46. SASS, E. and KATZ, A., 1982, The origin of platform dolomites:American Journal of Science, v. 282, p. 1184–1213.Google Scholar
  47. SHAABAN, M.N., HOLAIL, H.M., and RASHED, M.A., 1997, Dolomitization of Middle Miocene Buildups, Um Gheig area, Red Sea coast, Egypt:Carbonates and Evaporites, v. 12, p. 264–275.Google Scholar
  48. SHUKRI, N.M., 1954, Remarks on the geological structure of Egypt:Bulletin of the Society of Geography, Egypt, v. 27, p. 65–82.Google Scholar
  49. SIBLEY, D.F., 1982, The origin of common dolomite fabrics: Clues from the Pliocene:Journal of Sedimentary Petrology, v. 52, p. 1087–1100.Google Scholar
  50. SIBLEY, D.F., 1991, Secular changes in the amount and texture of dolomite:Geology, v. 19, p. 151–154.Google Scholar
  51. SIBLEY, D.F. and GREGG, J.M., 1987, Classification of dolomite rock textures:Journal of Sedimentary Petrology, v. 57, p. 967–975.Google Scholar
  52. SIMMS, M., 1984, Dolomitization by groundwater-flow systems in carbonate platforms:Transactions, Gulf Coast Association of Geological Society, v. 34, p. 411–420.Google Scholar
  53. STROUGO, A., 1985, Eocene stratigraphy of Giza Pyramids Plateau. Middle East Research Center, Ain Shams University, Egypt, v. 5, p. 79–99.Google Scholar
  54. STROUGO, A. and HAGGAG, M.A.Y., 1983, The occurrence of deposits of Paleocene age at Abu Roash, west of Cairo, Egypt:Neues Jahrbuch für Geologie und Paleontologie, v. 11, p. 677–686.Google Scholar
  55. SUN, Q.S., 1994, Perspective: a re-appraisal of dolomite abundance and occurrence in the Phanerozoic:Journal of Sedimentary Research, v. A64, p. 396–404.Google Scholar
  56. VAHRENKAMP, V.C., SWART, P.K., and RUIZ, J., 1991, Episodic dolomitization of Late Cenozoic Carbonates in the Bahamas: Evidence from strontium isotopes:Journal of Sedimentary Petrology, v. 61, p. 1002–1014.Google Scholar
  57. WALTER, L.M., 1985, Relative reactivity of skeletal carbonates during dissolution: implications for diagenesis. SEPM Special Publication, v. 36, p. 3–16.Google Scholar
  58. WEFER, G. and BERGER, W.H., 1991, Isotope palaeontology: growth and composition of extant calcareous species:Marine Geology, v. 100, p. 207–248.Google Scholar
  59. WHEELER, C.W., AHARON, P., and FERRELL, R.E., 1999, Successions of Late Cenozoic platform dolomites distinguished by texture, geochemistry, and crystal chemistry: Niue, south Pacific:Journal of Sedimentary Research, v. 69, p. 239–255.Google Scholar
  60. WILSON, J.L., 1975, Carbonate facies in geologic history. Berlin-Heidelberg-New York, Springer, 471 p.Google Scholar
  61. WRIGHT, D.T., 1997, An organogenic origin for widespread dolomite in the Cambrian Eilean Dubh Formation, Northwestern Scotland:Journal of Sedimentary Petrology, v. 67, p. 54–64.Google Scholar

Copyright information

© Springer 2004

Authors and Affiliations

  • A. S. Mansour
    • 1
  • H. M. Holail
    • 1
  1. 1.Geology Department, Faculty of ScienceAlexandria UniversityEgypt

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