Carbonates and Evaporites

, Volume 12, Issue 2, pp 185–191 | Cite as

Dolomitization and dedolomitization of Miocene carbonates at Gabal El-Safra, Sherm el Sheikh area, sinai, Egypt

  • El-Sayed A. A. Youssef


Dolomitization and dedolomitization of the Middle Miocene carbonate sequence at Gabal EISafra resulted in the formation of fine-crystalline dolomite (type 1), coarse crystalline “sucrosic” dolomite (type 2) and dedolostone. The first type occurs as either scattered crystals or patches of hypidiotopic to idiotopic, nearly stoichiometric dolomite crystals ranging from 5–20 μm, whereas the second type occurs as xenotopic to idiotopic dolomite crystals ranging in size from 50 to 200 μm and composed of trace-element depleted, more stoichiometric, coarsely crystalline clear rims that enclose Ca- and trace element-enriched cloudy cores of the dolomite crystals. However, the dedolostone occurs as (1) polycrystalline rhombic pseudomorphs of calcite and gypsum after dolomite, (2) relicts of incompletely dissolved dolomite and dedolomite crystals, (3) hollow dolomite rhombs and rhombohedral pores due to dissolution of the cloudy cores or the whole dolomite rhombs, respectively and (4) filling of hollow dolomite rhombs by gypsum. Replacement and dissolution of dolomite crystals began from the cores and expanded outward.

Stable isotope data shows that the finely crystalline dolomite has high δ18O values (mean=+1.81‰ PDB) and relatively low δ13C values (mean=−2.9‰ PDB), whereas the coarse crystalline dolomite has lower δ18O values (mean=+0.311‰ PDB) and δ13C values (mean=−2.08‰ PDB). The average Na+ and Sr+2 concentrations of the coarse crystalline dolomite are about 208 ppm and 118 ppm, respectively, whereas the mole % Mg CO3 ranges from 45 to 50. All the above results indicate that finely crystalline dolomite represents an early pre-burial phase of dolomitization under the influence of marine water, whereas the cores and rims of coarsely crystalline dolomite represent shallow and relatively deep burial phases of dolomitization under the influences of diluted and more diluted marine water respectively (mixed water model of dolomitization). However, the dedolostone represents a subaerial phase of diagenesis, after uplifting of dolostone, under the influence of phreatic environment.


Dolomite Middle Miocene Dolomitization Dolomite Crystal Crystalline Dolomite 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. ABDEL WAHAB, S., 1991, Sedimentology and depositional evolution of a lower Miocene clastic succession in Gabal El-Safra, Sherm El Sheikh area, Sinai, Egypt:Egyptian Journal of Geology, v. 34, p. 115–144.Google Scholar
  2. AL-HASHIMI, W.S. and HEMINGWAY, J.E., 1973, Recent dedolimitization and the origin of the rustly crusts of Northumberland:Journal of Sedimentary Petrology, v. 43, p. 82–91.CrossRefGoogle Scholar
  3. BACK, W., HANSHAW, B.B., PLUMMER, L.N., RAHN, P.H., RIGHMIR, C.T. and RUBIN, M., 1983, Process and rate of dedolomitization: mass transfer and14C dating in a regional carbonate aquifer:Geological Society of America Bulletin, v. 94, p. 1415–1429.CrossRefGoogle Scholar
  4. BEHRENS, E.W. and LAND, L.S., 1972, Subtidal Holocene dolomite, Baffin Bay, Texas:Journal of Sedimentary Petrology, v. 42, p. 155–161.Google Scholar
  5. BLATT, H., MIDDLETON, G.V. and MURRAY, R.C., 1980, Origin of sedimentary rocks, second edition: Englewood Cliffs, New Jersey, Prentice-Hall Inc., 782 p.Google Scholar
  6. CANAVERAS, J.C., SANCHEZ-MORAL, S., CALVO, J.P., HOYOS, M. and ORDONEZ, S., 1996, Dedolomites associated with Karstification. An example of early dedolomitization in lacustrine sequences from the Tertiary Madrid basin, Central Spain:Carbonates and Evaporites, v. 11, p. 85–103.CrossRefGoogle Scholar
  7. CHILINGAR, G.V., 1956, Dedolomitization: a review:American Association of Petroleum Geologists Bulletin, v. 40, p. 762–778.Google Scholar
  8. COURTILLOT, V., ARMIJO, R., and TAPPONNIER, P., 1987, The Sinai triple junction revisited.In Z. Bem Avraham (ed), Sedimentary basins within the Dead Sea and other rift zones:Tectonophysics, v. 141, p. 181–190.Google Scholar
  9. DE GROOT, K., 1967, Experimental dedolomitization:Journal of Sedimentary Petrology, v. 37, p. 1216–1220.Google Scholar
  10. EVAMY, B.D., 1963, The application of chemical staining technique to a study of dedolomitization:Sedimentology, v. 2, p. 164–170.CrossRefGoogle Scholar
  11. EVAMY, B.D., 1967, Dedolomitization and the development of rhombohedral pores in limestone:Journal of Sedimentary Petrology, v. 37, p. 1204–1215.CrossRefGoogle Scholar
  12. EYAL, M., EYAL, Y., BARTOV, Y. and STEINITZ, G., 1981, The tectonic development of the western margin of the Gulf of Elat (Aqaba) rift:Tectonophysics, v. 80, p. 39–66.CrossRefGoogle Scholar
  13. FOLK, R.L. and SIEDLECKA, A., 1974, Schizohaline environment: its sedimentary and diagenetic fabrics as exemplified by Late Paleozoic rocks of Bear Island, Svalbard:Sedimentary Geology, v. II, p. 1–15.CrossRefGoogle Scholar
  14. FOLK, R.L. and LAND, L.S., 1975, Mg/Ca ratio and salinity: two controls over crystallization of dolomite:American Association of Petroleum Geologist Bulletin, v. 59, p. 60–68.Google Scholar
  15. FRANK, J.R., 1981, Dedolomtization in the Taum sauk limestone (Upper Cambrian), southeast Missouri:Journal of Sedimentary Petrology, v. 51, p. 7–18.Google Scholar
  16. FRIEDMAN, G.M., 1995, Diverse origin of modern dolomite in the Levant:Carbonates and Evaporites, v. 10, p. 65–78.CrossRefGoogle Scholar
  17. GARFUNKEL, Z., BARTOV, J., EYAN, Y. and STEINITZ, G., 1974, Raham conglomerate-new evidence for Neogene tectonisms in the southern part of the Dead sea rift:Geological Magazine, v. III, p. 55–64.CrossRefGoogle Scholar
  18. GARFUNKEL, Z. and BARTOV, J., 1977, The tectonics of the Suez rift:Geological Survey of Israel Bulletin, v. 71, p. 1–44.Google Scholar
  19. GHORAB, M.A. and MARZOUK, I.M., 1967, A sureport on the rock-stratigraphic classification of the Miocene non-marine and coastal facies in the Gulf of Suez and Red Sea Coast. Unpublished Report, E.R. 601.Google Scholar
  20. GOLDBERG, M., 1967, Supratidal dolomitization and dedolomitization in Jurassic rocks of Hamakhtesh Hagatan, Israel:Journal of Sedimentary Petrology, v. 37, p. 760–773.Google Scholar
  21. HUME, W.F., 1906, The topography and geology of the Peninsula of Sinai (southern-eastern portion). Survey Dept., Cairo, 280 p.Google Scholar
  22. JAMES, N.P., BONE, Y. and KYSER, T.K., 1993, Shallow burial dolomitization and dedolomitization of Mid-Cenozoic, cool-water, calcitic, deep shelf limestones, southern Australia:Journal of Seedimentary Petrology, v. 63, p. 528–538.CrossRefGoogle Scholar
  23. JONES, B., PLEYDELL, S.M., N. K-C. and LONGSTAFFE, F.J., 1989, Formation of poikilotopic calcite- dolomite fabrics in the Oligocene Miocene Bluff Formation of Grand Cayman British West Indies:Bulletin of Canadian Petroleum Geology, v. 37, p. 256–256.Google Scholar
  24. KATZ, A., 1968, Calcian dolomites and dedolomitization:Nature, v. 217, p. 439–440.CrossRefGoogle Scholar
  25. KINSMAN, D.J.J., 1969, Modes of formation, Sedimentary association and diagenetic features of shallow water and supratidal evaporites:American Association of Petroleum Geologists Bulletin, v. 53, p. 830–840.Google Scholar
  26. LAND, L.S. and HOOPS, G.K., 1973, Sodium in carbonate sediments and rocks a possible index to the salinity of diagenetic solutions:Journal of Sedimentary Petrology, v. 43, p. 614–617.Google Scholar
  27. LAND, L.S., SALEM, M.R.I. and MORROW, D.W., 1975, Paleohydrology of ancient dolomites, geochemical evidence:American Association of Petroloum Geologists Bulletin, v. 59, p. 1802–1825.Google Scholar
  28. MATTES, B.W. and MOUNTJOY, E.W., 1980, Burial dolomitization of the upper Devonian Miette build up, Jasper National Park, Albertain D.H. Zenger, J.B. Dunham and R.L. Ethington (eds), Concepts and models of dolomitization:Society of Economic Paleontologists and Mineralogists, Special publication, v. 28, p. 259–297.Google Scholar
  29. MORROW, D.W. and KERR, J.W., 1978, Stratigraphy and sedimentology of Lower Paleozoic formations near Prince Alfred Bay, Devon Island:Geological Survey of Canada Bulletin, v. 254, 122 p.Google Scholar
  30. OMARA, S., 1959, The Geology of Sharm El Sheik sandstone, Sinai, Egypt:Egyptian Journal of Geology, v. 3, p. 107–121.Google Scholar
  31. PERTH, I., 1976, The stratigraphic geology of the Sherm El Sheikh area south Sinai: abst. 19 th seminar of the Geological survey of Israel, Randazzo, A.F., Sarver, T.J. and Mertin, D.B. 1983, Selected geochemical factors influencing diagenesis of Eocene carbonate rocks, Peninsula Florida, U.S.A.:Sedimentary Geology, v. 36, p. 1–14.Google Scholar
  32. RANDAZZO, A.F. and COOK, D.J., 1987, Characterization of dolomitic rocks from the coastal mixing zone of the Florida aquifer Florida, U.S.A.:Sedimentary Geology, v. 54, p. 169–192.CrossRefGoogle Scholar
  33. RICHARDSON, M. and ARTHUR, A.M., 1988, The Gulf of Sueznorthern Red Sea Neogene rift: a quantitative basin analysis:Marine and Petroleum Geology, v. 5, p. 248–269.CrossRefGoogle Scholar
  34. SELLOWED, B.W. and NETHERWOOD, R.E., 1984, Facies evolution in the Gulf of Suez area: Sedimentation history as an indicator of rift initiation and development:Modern Geology, v. 9, p. 43–69.Google Scholar
  35. SCHMIDT, V., 1965, Facies, diagenesis and related more diluted marine water respectively (mixed water model of dolomitization).In L.C. Pray and R.C. Murray (eds.), Dolomitization and limestone diagenesis: a symposium:Society of Economic Paleontologists and Mineralogists Special Publication, v. 13, p. 124–168.Google Scholar
  36. SHEARMAN, D.J., KHOURI, J. and TAHAS, S., 1961, On the replacement of dolomite by calcite in some Mesozoic limestone from the French Jura:Proceedings of the Geological Society of London, v. 12, p. 1–12.Google Scholar
  37. SMITH, D.E. and SWEET, K., 1968, Revaluation of dedolomitization:Journal of Sedimentary Petrology, v. 39, p. 379–380.CrossRefGoogle Scholar
  38. VON MORLOT, A, 1847, Ueber Dolomit und Seine Kuenstliche Darstellung aus Kalstein Haidinger Naturwiss Abhanlinger, v. 1, p. 305–315.Google Scholar
  39. WARRAK, M., 1974, The petrography and origin of dedolomitized, veined or brecciated carbonate rocks, the “cornieules” in the Freju region, French Alps:Journal of Geological Society of London, v. 130, p. 229–247.CrossRefGoogle Scholar
  40. WOLF, M.J., 1970, Dolomitization and dedolomitization in the Senonian chalk of Northern Ireland:Geological Magazine, v. 107, p. 39–50.CrossRefGoogle Scholar
  41. WORONICK, R.E. and LAND, L.S., 1985, Late burial diagenesis: Lower Cretaceous pearsall and Lower Glen Rose Formation, South Texas.In N. Schneidermann and P.M. Harris (eds), Carbonate Cements:Society of Economic Paleontologists and Mineralogists Special Publication 36, p. 265–275.Google Scholar
  42. YANAT EVA, O.K., 1955, Effect of aqueous solutions of gypsum on dolomite in the presence of carbon dioxide:Akademia Nauk SSSR Doklady, v. 101, p. 911–912.Google Scholar
  43. YOUSSEF, E.A., FAHMY, S.E. and IMAM, M., 1988: Stratigraphy and microfacies studies of the Miocene sequence at Gabal Sarbut El-Gamal, west-central Sinai, Egypt:Neues Jahrbuch Für Geologie und Paläontologie, v. 177, p. 222–242.Google Scholar
  44. ZENGER, D.H., 1973, Syntaxial calcite borders on dolomite crystals, little falls Formation (Upper Cambrian), New York:Journal of Sedimentary Petrology, v. 43, p. 118–124.Google Scholar

Copyright information

© Springer 1997

Authors and Affiliations

  • El-Sayed A. A. Youssef
    • 1
  1. 1.Geology Department Faculty of ScienceCairo UniversityGizaEgypt

Personalised recommendations