Document Type : Original Research Paper


1 Ph.D. Student, Department of Geology, North Tehran Branch, Islamic Azad University, Tehran, Iran

2 Professor, School of Earth Sciences, Shahid Beheshti University, Tehran, Iran

3 Associate Professor, Department of Geology, Basic Science Faculty, North Tehran branch,Islamic Azad University, Tehran, Iran.

4 Professor, Department of Geology, North Tehran Branch, Islamic Azad University, Tehran, Iran


The Dalichai Formation is the first rock unit of the Middle Jurassic in the Alborz sedimentary basin that has occurred in a marine environment. The boundary of the Dalichai formation with Shemshak Formation is erosional unconformable while it is concordant with Lar formation. Due to lithological similarity, the boundary of the Dalichai formation with the Lar formation is unclear. It is also very difficult to identify the primary carbonates mineralogy, due to the effects of diagenetic processes solely on the basis of petrographic studies. We studied a section of Sharaf mountain with a thickness of 1420m and 149 samples was studied. The study of the major and minor elements, the Oxygen and Carbon isotopes, and plotting of these values ​​against each other represents that the Dalichai formation have had original aragonite mineralogy, and the nonmarine diagenesis have had the highest impact on them. Plotting the Sr/Ca ratio versus Mn value, shows that these carbonates are affected in a semi-closed to open diagenetic system. Using Sr, Sr/Na, Sr/Ca, Oxygen and Carbon isotopes, the boundary of this formation with the Lar Formation is recognized in thickness of 1200m. The diagenetic environment temperature for this section limestones is 32.9ºC.


Main Subjects

Adabi, M.H.,1996- “Sedimentology and geochemistry of Upper Jurassic (Iran) and Precambrian (Tasmania) carbonate, Unpubl. Ph. D. Thesis, Uni. Tasmania, Australia 400.
Adabi, M.H. and Rao, C.P., 1991- Petrographic and geochemical evidence for original aragonitic mineralogy of Upper Jurassic carbonate (Mozduran Formation) Sarakhs area, Iran. Sedimentary Geology, v. 72, p. 253-267.
Adabi, M.H. and Asadi Mehmandosti, E., 2008- Microfacies and geochemistery of the Ilam Formation in the Tang-e-Rashid area, Izeh, S.W. Iran: Journal of Asian Earth Sciences, v. 33, p. 267-277.
Adabi, M.H., Salehi, M.A. and Ghobeishavi, A., 2010- Depositional environment, sequence stratigraphy and geochemistry of Lower Cretaceoues carbonates (Fahliyan Formation), South-West Iran. Journal of Asian Earth Sciences, v. 39, p. 148-160.
Adabi, M.H., Kakemem, U. and Sadeghi, A., 2016- Sedimentary facies, depositional environment, and sequence stratigraphy of Oligocene-Miocene shallow water carbonate form the Rig Mountain, Zagros basin (SW Iran) Carbonates and Evaporites, p. 1-17.
Alavi-Naini, M. and Hamedi, A.R., 1972- Map 1:100000 Jam; Geological Survey of Iran.
Anderson, T.F. and Arthur, M.A., 1983- Stable Isotopes of oxygen and carbonand theirapplication to sedimentologic and paleoenvironmental problems: in Stable Isotopes in Sedimentary Geology: Soc. Econ. Paleontal. Mineral., Short Course, v. 10, Section 1.1-1.151.
Brand, U.  and Veizer, J., 1981- Chemical Diagenesis of multicomponent carbonate system, II: stable Isotops: Journal. Sed. Petrology, v. 51, p. 987-997.
Choquette, P.W. and Pray, L.C., 1970- Geologic nomenclature and classification of porosity in sedimentary carbonates. American Association of Petroleum Geology bulletin, v. 54(2), p. 207-250.
Dickson, J.A.D., 1965- A modified staining technique for carbonate in thin section, Natures v. 205, p. 287.
Lohmann, K.C., 1988. Geochemical patterns of meteoric diagenetic systems and their application tostudies of paleokarast: In Paleokarast: New York, Springer-Verlag, p. 58-80.
Marshall, D.J. and Ashton, M., 1980- Isotopic and trace element evidence for submarine lithification of hardgrounds in the Jurassic of eastern England. Sedimentology, v. 27(3), p. 271-289.
Milliman, J.D., 1974- Recent Sedimentary Carbonates, Part 1, Springer-Verlag, Berlin, p. 375.
Rao, C.P., 1990. Petrography, trace elements and oxygen and carbon isotops Gordon Group carbonate (Ordovician), Florentone Vally, Tasmania, Australia, Sedimentary Geology, v. 66, p. 83-97.
Rao, C.P., 1996- Elemental composition of marine calcite from modern temperate shelf brachiopods, bryozoans and bulk carbonates, eastern Tasmania, Australia: Carbonates and Evaporites, v. 11, p. 1-18.
Rao, C.P. and Adabi, M.H., 1992- Carbonate minerals, major and minor elements and oxygen and carbon isotops and their variation with water depth in cool, temperate carbonates, western Tasmania, Australia, Marine Geology, v. 103, p. 249-272.
Seyed- Emami, K. and Alavi, M., 1990- Bajocian Stage in Iran: Mem. Description. Carta Goel. Ital 40, p. 215-222.
Veizer, J., 1983. Trace elements and stable isotopes in sedimentary carbonates: In Reeder, R. J., (Eds), Carbonates, Mineralogy and Chemistry. Reviews in Mineralogy, Blacksburg, v. 11, p. 265-299.
Warren, J. K., 1989- Evaporite Sedimentology: Importance in Hydrocarbon Accumulation: Englewood Cliffs, NJ, Prentice Hall Advanced Reference Series, 285 p.
Winefield, P.R., Nelson, C.S. and Hodder, A.P.W., 1996- Discriminating temperate carbonates and their diagenetic environments using bulk elemental geochemistry: a reconnaissance study based on New ZealandCenozoic limestones. Carbonates and Evaporites, v.11, p. 19-31.