Microfacies and depositional environment of Tarbur Formation (Upper Cretaceous‐Lower Palaeocene) Zagros area, southwestern Iran

Abstract

Over 3,000 m of Upper Cretaceous‐Lower Palaeocene sediments belonging to the Tarbur Formation were studied in seven stratigraphic sections around Shiraz city (south Zagros Basin, SW of Iran). The Tarbur Formation is divided into two informal lithostratigraphic units: a lower well‐bedded rudist limestone and an upper massive rudist limestone. Both units comprise rudist particles as a major organo‐detrital component. Microscopic studies have identified the presence of the following carbonate microfacies types in the Tarbur Formation: rudist orbitoid wackestone, miliolid algal‐bioclast wackestone, rudist packstone, rudist orbitoid packstone, rudist intraclast miliolid packstone, rudist‐agglutinated foraminifer grainstone, orbitoid rudist grainstone, rudist‐hyaline foraminifer‐intraclast grainstone, rudist boundstone and coral boundstone, which are attributed to shallow water lagoon, bar and fore‐reef palaeoenvironments. The rudist fragments co‐existed with a Campanian/Maastrichtian foraminiferal assemblage. The stratigraphic distribution of the investigated microfacies was affected by vertical displacement of studied area basement faults.

Microfacies analysis and depositional environment of the Upper Cretaceous rocks in Tang‐e Vanak section (Central Zagros Basin, SW Iran)

“…Studies by Afghah (2016, 2022), Afghah and Yousefzadeh (2006), Abyat et al (2007), Vaziri‐Moghaddam et al (2005) in Fars (South Zagros) have shown that the formation of reefs in the Tarbur Formation had more ideal conditions and spread wildly. There were true reefs that were deposited in the back reefs lagoons of the Sachun Evaporation Formation.…”

“…Studies by Afghah (2016Afghah ( , 2022, Afghah and Yousefzadeh (2006), Abyat et al (2007), Vaziri-Moghaddam et al (2005)…”

Distribution and palaeoecology of scleractinian corals during the Maastrichtian (Late Cretaceous)

“…Faujas-Saint-Fond, 1798-1803Goldfuss, 1826Goldfuss, -1844Milne Edwards & Haime, 1857;Nötling, 1897;Trauth, 1911;Dietrich, 1917;Umbgrove, 1925;Wells, 1933Wells, , 1934Alloiteau, 1936Alloiteau, , 1952bAlloiteau, , 1958Kuzmicheva, 1985Kuzmicheva, , 1987Tchéchmédjiéva, 1986Tchéchmédjiéva, , 1995Filkorn, 1994;Leloux, 1999Leloux, , 2004Baron-Szabo, 2000, 2006, 2008Filkorn et al, 2005;Jell et al, 2011;Löser, 2012;Baron-Szabo et al, 2023) as well as in analyses primarily dealing with Maastrichtian stratigraphy and sedimentology (e.g. Gill et al, 1966;Sohl & Koch, 1984;Görmüş et al, 2019;Afghah, 2022). Frequently, corals have been documented from rudist-dominated limestones (e.g.…”