Sequence Stratigraphy of Lower Carboniferous Rocks in Bakhshi Section, East-Central Iran
- 1 Department of Geology, Islamic Azad University, North Tehran Branch, Tehran, Iran
- 2 Department of Earth Sciences, Shahid Beheshti University, Tehran, Iran
- 3 Research Institute for Earth Sciences, Geology Survey of Iran, Tehran, Iran
- 4 Department of Geology, Islamic Azad University, North Tehran Branch, Tehran, Iran
- 5 Department of Geology, Islamic Azad University, North Tehran Branch, Tehran, Iran
Abstract
The deposits of Lower Carboniferous rocks in Kalmard Block are characterized by Gachal informal formation, showing various properties in different outcrops. These deposits (in Gachal formation) are composed chiefly of carbonate, evaporite and siliciclastic rocks. This formation commonly hosts 190 m sandstone, limestone, dolomitic limestone and dolomite as well as a small amount of shale and marl in the Bakhshi section. It unconformably underlies Devonian deposits (Rahdar formation) while lateritic soils of lower Permian (Chili formation) are depicted overlying an erosional unconformity above this formation. The mixed carbonate-evaporite-siliciclastic sequence of Gachal formation is made up of three third-order depositional sequences, separated from each other by Type 1 sequence boundary (SB1). Siliciclastic and evaporite deposits include LST system tract, whereas carbonate microfacies involve TST and HST system tracts, separated from each other by MFS. The depositional sequences identified in Gachal formation point to the Lower Carboniferous age, conforming to upper Kaskaskia supersequence. The upper erosional boundary between Gachal and Chili formations complies with the global-scale sea level fall.
- Aghanabati, A. (2004) Geology of Iran. Geological Survey of Iran, Tehran, 606 p.
- Aghanabati, A. (1977) Etudgeologique de la region de Kalmard (W. Tabas). Geological Survey of Iran, No. 35, 51-63.
- Azhdari, A. (1999) Geological Map and Report of Robat-e-Khan, on Scale of 1:100000. Geological Survey of Iran, Tehran.
- Dickson, J. (1965) A Modified Staining Technique for Carbonate in Thin Section. Nature, 205, 587 p.
- Posamentier, H.M., Jervey, M.T. and Vail, P.R. (1988) Eustatic Controls on Clastics Deposition I-Conceptual Framework. In: Wilgus, C.K., Hasting, B.H., Posamentier, H., Van Wagoner, J.C., Ross, C.A. and Christopher, G., Eds., Sea Level Change an Integrated Approach, SEPM, Special Publication, Vol. 42, 109-124. https://doi.org/10.2110/pec.88.01.0109
- Naish, T.R., Abbott, S.T. and Carter, R.M. (2013) Sequence Stratigraphy Reference Module in Earth Systems and Environmental Sciences. In: Elias, S.A., Ed., Encyclopedia of Quaternary Science, 2nd Edition, Elsevier, Amsterdam, 260-276.
- Patricio, R.D., Luis, A.B., Carlos, O.L. and Gabriela, A.C. (2009) Latest Carboniferous-Earliest Permian Transgressive Deposits in the Paganzo Basin of Western Argantina: Lithofacies and Sequence Stratigraphy of a Coastal Plain to Bay Succession. Journal of South American Earth Sciences, 28, 40-53. https://doi.org/10.1016/j.jsames.2008.10.003
- Schlager, W. (2005) Carbonate Sedimentology and Sequence Stratigraphy. SEPM Concepts in Sedimentology and Paleontology, 8, 200 p. https://doi.org/10.2110/csp.05.08
- Sloss, L.L. (1963) Sequence in Cratonic Interior of North America. Geological Society of America Bulletin, 74, 93-114. https://doi.org/10.1130/0016-7606(1963)74[93:SITCIO]2.0.CO;2
- Alonso-Zarza, A.M. and Tanner, L.H. (2010) Carbonates in Continental Settings: Facies, Environments and Processes. Developments in Sedimentology, 61, 225-267.