scholarly journals Late Triassic scleractinian corals from Nayband Formation, southwest Ardestan, Central Iran

2020 ◽  
Vol 72 (2) ◽  
pp. A090619
Author(s):  
Maryam Mannani
Keyword(s):  
Scleractinian Corals ◽  
Central Iran ◽  
Late Triassic ◽  
Nayband Formation

First hexactinellid sponge reported from the Upper Triassic Nayband formation of central Iran

2007 ◽  
Vol 81 (6) ◽  
pp. 1538-1542 ◽  
Author(s):  
J. Keith Rigby ◽  
B. Senowbari-Daryan
Keyword(s):  
Scleractinian Corals ◽  
Upper Triassic ◽  
Central Iran ◽  
Hexactinellid Sponge ◽  
Nayband Formation ◽  
Hexactinellid Sponges

Sponges, along with scleractinian corals, are among the main reef-building organisms in Triassic reefs. Hypercalcified groups, including the chambered sphinctozoans, and the unchambered inozoans, chaetetids, and spongiomorphids, represent the most abundant Triassic reef-building sponges. Earlier workers have described elements of the latter group as “hydrozoans.” Hexactinellid sponges, abundant in some Permian reefs (e.g., in Texas, Finks, 1960), are rarely known from similar Triassic deposits, in general (Tichy, 1975), and particularly from Upper Triassic stratigraphic units. Hexactinellid sponges have been sporadically reported from well-investigated Upper Triassic reefs in the western Tethyan region (e.g., Keupp et al., 1989). However, a variety of hexactinellid sponges have been reported from Upper Triassic deposits and reefal limestones of the northern and central Tethyan realm (Boiko, 1990; Wu, 1989; Wu and Xiao, 1989; Rigby et al., 1998).

Norian to Rhaetian scleractinian corals in the Ferdows Patch Reef (Nayband Formation, east central Iran)

2012 ◽  
Vol 86 (5) ◽  
pp. 801-812 ◽  
Author(s):  
Hannah M. E. Shepherd ◽  
George D. Stanley ◽  
Fatemeh Amirhassankhani
Keyword(s):  
Patch Reef ◽  
Scleractinian Corals ◽  
Central Iran ◽  
East Central ◽  
Patch Reefs ◽  
Faunal Assemblages ◽  
New Information ◽  
Nayband Formation ◽  
The Subject ◽  
Northeast Iran

The Nayband Formation is one of the best known sedimentary units in central Iran. The type section consists of a thick succession of shale, siltstone, reef limestone and sandstone that is subdivided into five distinct members: Gelkan, Bidestan, Hoz-e-Sheykh, Howz-e- Khan and Qadir. Abundant and well-preserved framework-building scleractinian corals are included among the macrofossils of the Nayband Formation; these corals characterize the formation and are the subject of this study. The Hassan-Abad section, located in northeast Iran in Lute Block (northwest of Ferdows city), was chosen for detailed study and sampling. Analysis of sedimentary lithofacies and faunal assemblages in the Bidestan and the Howz-e-khan members indicate both biostromal and biohermal characters for the former shallow-water patch reefs and support a Norian to Rhaetian age. The useful biostratigraphic hydrozoanHeterastridium conglobatumwas studied along with 14 taxa of scleractinian corals:Stylophyllopsis rudis, Distichophyllia norica, Paradistichophyllum dichotomum, Retiophyllia frechi, Retiophyllia norica, Retiophyllia robusta, Chondrocoenia schafhaeutli, Chondrocoenia ohmanni, Astraeomorpha crassisepta, Astraeomorpha confusa, Astraeomorpha minor, Procyclolites triadicus, Pamiroseris rectilamellosa,andEocomoseris ramosa. These fossils clarify the stratigraphy of the Nayband Formation, as well as provide new information on the patch reefs and the framework constructors of these reefs.

Some Late Triassic gastropods from the Nayband formation in Central Iran

Facies ◽  
2003 ◽  
Vol 48 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Alexander Nützel ◽  
Ali Hamedani ◽  
Baba Senowbari-Daryan
Keyword(s):  
Central Iran ◽  
Late Triassic ◽  
Nayband Formation

Scleractinian corals from lower cretaceous deposits north of Esfahan (central Iran)

Facies ◽  
2003 ◽  
Vol 48 (1) ◽  
pp. 199-215 ◽  
Author(s):  
Rosemarie C. Baron-Szabo ◽  
Ali Hamedani ◽  
Baba Senowbari-Daryan
Keyword(s):  
Lower Cretaceous ◽  
Scleractinian Corals ◽  
Central Iran ◽  
Cretaceous Deposits

Evolution of the coral-zooxanthellae symbiosis during the Triassic: a geochemical approach

Paleobiology ◽  
1995 ◽  
Vol 21 (2) ◽  
pp. 179-199 ◽  
Author(s):  
George D. Stanley ◽  
Peter K. Swart
Keyword(s):  
Shallow Water ◽  
Isotope Analysis ◽  
Indirect Evidence ◽  
Scleractinian Corals ◽  
Late Triassic ◽  
Control Group ◽  
Algal Symbiosis ◽  
Isotope Studies ◽  
Carbonate Complexes ◽  
Geochemical Approach

Scleractinian corals first appeared during Triassic time in tropical shallow water environments. Controversy surrounds the paleoecology of scleractinian corals of the Late Triassic. Were they like their living counterparts, capable of supporting reefs, or had they not yet coevolved the important association with zooxanthellae that facilitated reef growth and construction? Indirect evidence suggests that some Upper Triassic corals from the Tethys played important constructional roles as reef builders within tropical carbonate complexes of the Tethys. To evaluate this idea, we have employed a geochemical approach based on isotope fractionation to ascertain if Late Triassic corals once possessed zooxanthellae.We have determined evidence for the ancient presence of algal symbiosis in 13 species of Triassic scleratinians from reef complexes in Turkey and northern Italy. In contrast, two higher latitude Jurassic species used as a control group for isotope analysis, lacked isotopic indications of symbiosis. These findings, together with stratigraphic and paleoecologic criteria, support the contention that Late Triassic scleractinian corals inhabiting shallow-water carbonate complexes of the Tethys were predominantly zooxanthellate, like their living counterparts from present day reefs.We view the zooxanthellate condition in calcifying reef organisms as a necessary prerequisite for constructional reef development. Our results emphasize the power of stable isotope studies in helping to answer paleobiological questions.

Stenolaemate bryozoans from the upper triassic (Norian-Rhaetian) Nayband Formation, Central Iran

Facies ◽  
2003 ◽  
Vol 48 (1) ◽  
pp. 135-150 ◽  
Author(s):  
Priska Schäfer ◽  
Baba Senowbari-Daryan ◽  
Ali Hamedani
Keyword(s):  
Upper Triassic ◽  
Central Iran ◽  
Nayband Formation

scholarly journals Photosymbiosis in Late Triassic scleractinian corals from the Italian Dolomites

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11062
Author(s):  
Katarzyna Frankowiak ◽  
Ewa Roniewicz ◽  
Jarosław Stolarski
Keyword(s):  
Coefficient Of Variation ◽  
Isotope Composition ◽  
Scleractinian Corals ◽  
Regular Growth ◽  
Late Triassic ◽  
Western Tethys ◽  
Growth Increments ◽  
Algal Symbiosis ◽  
Growth Bands ◽  
Zooxanthellate Corals

During the Carnian, oligotrophic shallow-water regions of the western Tethys were occupied by small, coral-rich patch reefs. Scleractinian corals, which already contributed to the formation of the reef structure, owed their position most probably to the symbiosis with dinoflagellate algae (zooxanthellae). Using microstructural (regularity of growth increments) and geochemical (oxygen and carbon stable isotopes) criteria of zooxanthellae symbiosis, we investigated whether this partnership was widespread among Carnian scleractinians from the Italian Dolomites (locality Alpe di Specie). Although corals from this locality are renowned from excellent mineralogical preservation (aragonite), their skeletons were rigorously tested against traces of diagenesis Irrespective of their growth forms, well preserved skeletons of corals from the Dolomites, most frequently revealed regular growth bands (low values of coefficient of variation) typical of modern zooxanthellate corals. Paradoxically, some Carnian taxa (Thamnasteriomorpha frechi and Thamnasteriomorphasp.)with highly integrated thamnasterioid colonies which today are formed exclusively by zooxanthellate corals, showed irregular fine-scale growth bands (coefficient of variation of 40% and 41% respectively) that could suggest their asymbiotic status. However, similar irregular skeletal banding is known also in some modern agariciids (Leptoseris fragilis) which are symbiotic with zooxanthellae. This may point to a similar ecological adaptation of Triassic taxa with thamnasterioid colonies. Contrary to occasionally ambiguous interpretation of growth banding, all examined Carnian corals exhibited lack of distinct correlation between carbon (δ13C range between 0.81‰ and 5.81‰) and oxygen (δ18O values range between −4.21‰ and −1.06‰) isotope composition of the skeleton which is consistent with similar pattern in modern zooxanthellates. It is therefore highly likely, that Carnian scleractinian corals exhibited analogous ecological adaptations as modern symbiotic corals and that coral-algal symbiosis that spread across various clades of Scleractinia preceded the reef bloom at the end of the Triassic.

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