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).

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 Wildfire Events at the Triassic-Jurassic Boundary of the Tabas Basin, Central Iran

2020 ◽  
Author(s):  
Majid M Alipour ◽  
Bahram Alizadeh ◽  
AmirAbbas Jahangard ◽  
AhmadReza GandomiSani
Keyword(s):  
Major Change ◽  
Lower Jurassic ◽  
Upper Triassic ◽  
Central Iran ◽  
Sharp Boundary ◽  
Depositional Settings ◽  
Run Off ◽  
Clastic Sediments ◽  
Nayband Formation ◽  
Microscopic Charcoal

Abstract This paper presents organic geochemical evidence pointing to the occurrence of wildfire events at the Triassic-Jurassic boundary in Central Iran. The studied outcrop section (the Kamarmacheh Kuh section) is comprised of the Upper Triassic Nayband Formation which passes conformably into the Lower Jurassic Ab-e-Haji Formation with no sharp boundary. Organic petrographical studies reveal a higher concentration of semi-fusinite macerals and microscopic charcoal at the boundary between studied formations. This observation can be an evidence for widespread wildfire events at the Triassic-Jurassic boundary of the studied area. Following these fires, vast areas of land were exposed for erosion and large volumes of clastic sediments were provided due to increased run-off. This agrees well with previous sedimentological and stratigraphical studies suggesting a major change in the depositional conditions from marine to non-marine at the Triassic-Jurassic boundary of the Tabas Basin. These findings can have important implications about paleo-depositional settings of the studied formations and the nature of the associated organic matter.

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.

Depositional history and sequence stratigraphy of central Tethyan from the Upper Triassic Nayband Formation, Central Iran

2020 ◽  
Vol 35 (1) ◽  
Author(s):  
Asghar Etesampour ◽  
Asadollah Mahboubi ◽  
Reza Moussavi-Harami ◽  
Nasser Arzani ◽  
Hoseinali Bagi
Keyword(s):  
Sequence Stratigraphy ◽  
Upper Triassic ◽  
Central Iran ◽  
Depositional History ◽  
Nayband Formation

The palynology of the Nayband Formation (Upper Triassic) of the Tabas Block, Central Iran

2020 ◽  
Vol 282 ◽  
pp. 104308
Author(s):  
Hossein Sabbaghiyan ◽  
Mohammadreza Aria-Nasab ◽  
Ebrahim Ghasemi-Nejad
Keyword(s):  
Upper Triassic ◽  
Central Iran ◽  
Nayband Formation

Triassic roots of the amphiastraeid scleractinian corals

2001 ◽  
Vol 75 (1) ◽  
pp. 34-45 ◽  
Author(s):  
Ewa Roniewicz ◽  
Jarosław Stolarski
Keyword(s):  
Type Species ◽  
Adult Stage ◽  
Bilateral Symmetry ◽  
Radial Symmetry ◽  
Scleractinian Corals ◽  
Upper Triassic ◽  
Phylogenetic Status ◽  
Phylogenetic Hypotheses ◽  
First Time

The Early Carnian (Upper Triassic) phaceloid coral originally described by Volz (1896) asHexastraea fritschi, type species ofQuenstedtiphylliaMelnikova, 1975, reproduced asexually by “Taschenknospung” (pocket-budding), a process documented herein for the first time. This type of budding is recognized only in the Amphiastraeidae, a family thus far recorded only from Jurassic-Cretaceous strata. Similar to amphiastraeids,Quenstedtiphyllia fritschi(Volz, 1896) has separate septal calcification centers and a mid-septal zone built of serially arranged trabeculae. The most important discriminating characters of the new amphiastraeid subfamily Quenstedtiphylliinae are one-zonalendotheca and radial symmetry of the corallite in the adult stage (in contrast to two-zonal and bilateral symmetry in the adult stage in Amphiastraeinae).Quenstedtiphyllia fritschishares several primitive skeletal characters (plesiomorphies) with representatives of Triassic Zardinophyllidae and, possibly, Paleozoic plerophylline rugosans: e.g., thick epithecal wall and strongly bilateral early blastogenetic stages with the earliest corallite having one axial initial septum. To interpret the phylogenetic status of amphiastraeid corals, we performed two analyses using plerophylline rugosans and the solitary scleractinianProtoheterastraea, respectively, as the outgroups. The resulting phylogenetic hypotheses support grouping the Zardinophyllidae with the Amphiastraeidae in the clade Pachythecaliina (synapomorphy: presence of pachytheca). Taschenknospung is considered an autapomorphy for the Amphiastraeidae. This study is the first attempt to analyze the relationships of the Triassic corals cladistically.

Silurian hexactinellid sponges from northern British Columbia, Canada

1998 ◽  
Vol 72 (2) ◽  
pp. 202-220 ◽  
Author(s):  
J. Keith Rigby ◽  
Joanne L. Nelson ◽  
B. S. Norford
Keyword(s):  
British Columbia ◽  
New Species ◽  
Black Shale ◽  
Continental Margin ◽  
Early Paleozoic ◽  
Hexactinellid Sponge ◽  
Hexactinellid Sponges

Faunules of largely hexactinellid sponges have been collected from siltstones of Early Silurian Wenlock or latest Landovery age within the upper Road River Group from northern British Columbia. The assemblages include the new species: Protospongia columbiana, Hexatractiella pseudonevadensis and Cyathophycus akiensis. Other taxa described include the hexactinellids Protospongia conica Rigby and Harris, 1979, Hexatractiella nevadensis (Rigby and Stuart, 1988), Diagoniella sp., Gabelia pedunculus? Rigby and Murphy, 1983, and a specimen of the monaxonid demosponge Wareiella typicala Rigby and Harris, 1979. Also included is a fragment of what must have been a steeply obconical-cylindrical hexactinellid sponge of uncertain taxonomy; it has a skeleton of robust hexactines in an unquadruled net, above a root-tuft of 10-20 spicules. Other sponge impressions include small circular clusters of hexactines with radiating, to basketlike patterns and somewhat similar, isolated and dissociated, long probably roof tuft spicules and possible basal root tuft rosettes of monaxons. The faunules are similar to other outer continental margin, black shale, sponge assemblages of the Early Paleozoic Era, and include elements previously described from northern British Columbia and central Nevada.

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