A review of the Oligo–Miocene larger benthic foraminifera in the Zagros basin, Iran; New insights into biozonation and palaeogeographical maps

Benthic foraminiferal biostratigraphy of the Oligocene Sequence of the Asmari Formation in the Interior Fars Sub-Zone, Zagros Belt, SW Iran

“…Higher-level classification of the benthic foraminifera follows Loeblich & Tappan (1987), but identification of specific taxa is based on the works of Hakimzadeh & Seyrafian (2008), Amirshahkarami (2013), Kakemem et al (2016), Habibi (2016aHabibi ( , b, 2018, Taheri et al (2017), andBover-Arnal (2018). The benthic foraminiferal biozones proposed herein are defined according to Allahkarampour Dill et al (2020).…”

“…Benthic foraminiferal assemblages have been widely used to date the shallow marine carbonate deposits of the Asmari Formation in the Zagros belt, SW Iran (e.g., Vaziri-Moghaddam et al, 2006Hakimzadeh & Seyrafian, 2008;Kalanat et al, 2010;Sooltanian et al, 2011;Rahmani, et al, 2012;Amirshahkarami, 2013;Saleh, 2014;Zabihi Zoeram et al, 2015;Zare et al, 2015;Sattari et al, 2016;Kakemem et al, 2016;Habibi, 2016aHabibi, , b, 2018Khoshnood et al, 2016;Taheri et al, 2017;Habibi & Bover-Arnal, 2018;Moradi et al, 2019;Goodarzi et al, 2020;Allahkarampour Dill et al, 2020;Monjezi & Saeedi Razavi, 2021). The key biozonations of the Asmari Formation based on benthic foraminifera (mainly Nummulites, Borelis melo group, Austrotrillina howchini, Peneroplis, Archaias, Miogypsina, Miogypsinoides, lepidocyclinids, Operculina, Spiroclypeus, Elphidium and Dendritina rangi) were erected by Wynd (1965), Adams & Bourgeois (1967), Laursen et al (2009), Van Buchem et al (2010) and Allahkarampour Dill et al (2020) (Figure 8). Wynd (1965) established the first biozones in the Asmari Formation and identified three biozones in the Oligocene and two biozones in the Miocene deposits of the formation (Figure 8).…”

“…The carbonate dominated Asmari Formation in the Zagros belt in southwestern Iran represents the largest hydrocarbon reservoir in Iran, and is one of the most significant reservoirs in the Middle East (Beydoun et al, 1992;Motiei, 1993;Alavi, 2004;Aghanabati, 2011;Burchette, 2012;Moradi et al, 2017). The age of the formation ranges from Oligocene to Early Miocene (Rupelian to Burdigalian: Wynd, 1965;Adams & Bourgeois, 1967;Ehrenberg et al, 2007;Laursen et al, 2009;Van Buchem et al, 2010;Kakemem et al, 2016;Allahkarampour Dill et al, 2020). Lithologically, the Asmari For mation consists mainly of limestones (argillaceous limestones, dolomitic limestones, pure limestones) with subordinate sandstones and evaporite deposits (James &Wynd, 1965;Motiei, 1993;Aghanabati, 2011;Roozpeykar & Maghfouri Moghaddam, 2016;Taheri et al, 2017).…”

“…The deposition of the evaporite deposits of the Asmari Formation was controlled by significant eustatic sea-level fall that led to the formation of an isolated submarine saline basin (Van Buchem et al, 2010;Roozpeykar & Maghfouri Moghaddam, 2016). The fossil content of the Oligocene and Lower Miocene limestones of the Asmari Formation consists mainly of benthic foraminifera, coralline red algae and corals (Allahkarampour Dill et al, 2020). Benthic foraminifera, as one of the most abundant and diverse faunal components in the shallow marine carbonate deposits of the Asmari Formation in the Zagros belt, are represented by biostratigraphically and paleoecologically important taxa, such as nummulitids, lepidocyclinids, amphisteginids, soritids, peneroplids, alveolinids, miliolids (particularly austrotrilinids) and rotaliids (Adams & Bourgeois, 1967;Seyrafian, 2000;Ehrenberg et al, 2007;Vaziri-Moghaddam et al, 2006;Laursen et al, 2009;Van Buchem et al, 2010;Seyrafian et al, 2011;Habibi, 2016aHabibi, , b, 2018Allahkarampour Dill et al, 2020).…”

The Oligocene to Lower Miocene depositional sequences of the Zagros Basin, SW Iran

“…throughout the Zagros Basin. So far, extensive research has been conducted by many researchers on the Oligocene and Miocene deposits of the Zagros Basin, with biostratigraphical, palaeoenvironmental, sequence stratigraphical, and petrophysical studies (Abdullah et al, 2019;Adabi et al, 2016;Ehrenberg et al, 2007;Farshia et al, 2019;Joudaki et al, 2020;Joudaki & Baghbani, 2018;Kamalifar et al, 2020;Laursen et al, 2009;Luo et al, 2019;Nikfard-Dill et al, 2020;Roozpeykar & MaghfouriMoghadam, 2015;Sadooni & Alsharhan, 2019;Seyrafian et al, 2011;Shabafrooz et al, 2015;Van Buchem et al, 2010;Vaziri-Moghaddam et al, 2006). However, given the plate-scale extension of the Asmari Fm., there are still regions in the Middle East where this sedimentary record remains underexplored (Habibi & Bover-Arnal, 2018).…”