Heterozoan carbonates in oligotrophic tropical waters: The Attard member of the lower coralline limestone formation (Upper Oligocene, Malta)

Biostratigraphy and paleoecology of the Oligo-Miocene Asmari Formation in the Izeh zone (Zagros Basin, SW Iran)

“…At these areas rotalids, miliolids and imperforate foraminifera are frequent in the inner ramp, while red algae and lepidocyclinids are abundant in the middle ramp. The foraminiferal assemblage of the Asmari Formation shows close affinities to that described by Brandano et al (2009a) of the Malta carbonate platform. Such assemblages suggest that carbonate sedimentation took place in tropical to sub-tropical waters, under oligotrophic to slightly mesotrophic conditions.…”

“…Heterozoan carbonates can develop on a carbonate ramp (Carannante et al, 1988;Jones and Desrochers, 1992;Boreen and James, 1995;Feary, 1995;Brachert et al, 1998). The spread of heterozoan assemblages related to the low capacity of corals to thrive in high-light conditions and to form a wave-resistant reef promoted the distribution of heterozoan assemblages (Brandano et al, 2009a;Rahmani et al, 2009;Allahkarampour Dill et al, 2010). Oligo-Miocene carbonates are extensive throughout SW Iran.…”

“…This biotic association indicates a deposition within the photic zone, in a sea-grass-dominated environment as suggested by the presence of epiphytic porcellaneous foraminifera such as Peneroplis and miliolids (Wilson, 1975;Langer, 1993;Beavington-Penney and Racey, 2004;Reich et al, 2015 given by the poorly sorted and micrite-rich textures and absence of sedimentary structures. The associated fauna (Peneroplis, Borelis, discorbids and thick samples of Amphistegina) are also typical for seagrass meadows (Murray, 1973;Brasier, 1975;Beavington-Penney and Racey, 2004;Brandano et al, 2009a;Reuter et al, 2010;Pomar et al, 2014). One of the most important and excellent markers for the Aquitanian is Favreina asmaricus (coprolitic facies) (Figure 15) (Table 4) with occurrences related to the particular environmental condition (isolated hypersaline basins for part of the time) (Laursen et al, 2009;Van Buchem et al, 2010).…”

Sedimentary Environment and Relative Sea Level Changes of the Asmari Formation Deposited in Lurestan Basin, Southwest of Zagros

“…Therefore, large benthic foraminifera abundance, echinoid, and also red algae all confirm that MF 13 is deposited in oligophotic mid ramp [51] [52] [53]. Similar microfacies of Asmari are reported in other parts of the Zagros Region [54].…”

Heterozoan carbonates in subtropical to tropical settings in the present and past

“…Previously, the limited capacity of zooxanthellate corals to thrive in high-light conditions is thought to have prevented them from forming a waveresistant reef Hallock 2007, 2008). This promoted the dominance of heterozoan assemblages in oligotrophic tropical waters, e.g., in the Upper Oligocene sediments of Malta that form a carbonate ramp dominated by coralline algae (Brandano et al 2009). Similarly, in SE Asia, Paleogene carbonates were dominated by coralline algae and benthic foraminifers with only scarce corals despite tropical latitudes (Wilson and Rosen 1998;Wilson 2008).…”