Facies analysis and depositional environment of the Oligocene–Miocene Asmari Formation, in Interior Fars (Zagros Basin, Iran)

• Sara Karami ^[1] ; Vahid Ahmadi ^[1] ; Hamzeh Sarooe ^[1] ; Mohammad Bahrami ^[2]
  1. [1] Islamic Azad University

     Islamic Azad University

     Irán

     
  2. [2] Payam-e-Noor University of Shiraz
• Localización: Carbonates and Evaporites, ISSN 0891-2556, Vol. 35, Nº. 3, 2020
• Idioma: inglés
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• Resumen

  • The present study deals with depositional environment and microfacies analysis of the Asmari Formation in the Nasr–Abad section of Zagros basin in SW of Iran. The thickness of 240 m with Nasr–Abad stratigraphic section to define microfauna is taken from Asmari Formation. Asmari Formation is located in SE of Shiraz. According to the identified index microfossils, following three Oligocene assemblages are determined: 1: Nummulites fichteli–Nummulites vascus, 2: Archaias asmaricuas–Archiaias hensoni, and 3: Peneroplis evolutus–Austroterillina howchini. According to the field observation, thin section studies and the results of petrographic analyses, four microfacies contain open marine (MF1-3), shoal (MF-4), lagoon (MF5-7) and tidal flat (MF8-9) depositional environments are identified. Based on the paleoenvironmental interpretations, the lack of barrier reefs as well as of gradual facies change, a homoclinal ramp mainly represented by its inner and middle sectors is proposed and reconstructed for depositional environment of the Asmari Formation in the studied section.