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

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).

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.

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

scholarly journals Sedimentary environment and provenance of sandstones from the Qadir member in the Nayband Formation, Tabas block, east-central Iran

2021 ◽  
Vol 73 (1) ◽  
pp. A140920
Author(s):  
Ehsan Zamaniyan ◽  
Mohammad Khanehbad ◽  
Reza Moussavi-Harami ◽  
Asadollah Mahboubi
Keyword(s):  
Continental Margin ◽  
Chemical Weathering ◽  
Sedimentary Environment ◽  
Active Continental Margin ◽  
Central Iran ◽  
Geochemical Data ◽  
Delta Front ◽  
Field Evidence ◽  
Nayband Formation ◽  
The Impact

Qadir Member of Nayband Formation, located in East of Central Iran, has developed to a great extent. Investigation of the lithofacies and sedimentary environment, resulted in identification of the deltaic and marine deposits. Based on field evidence and facies features, Qadir Member consists of two lithofacies, including carbonate and siliciclastic facies. The siliciclastic facies were identified as having four sandstone facies including Sr, Sh, Sp, St, three fine-grained lithofacies, including FI, Fm, Fl (Sr) / Sr (FI) and one coal facies. Also, regarding the field, laboratory studies, and identification of lithofacies, the coastal plain, deltaic (including deltaic plain, proximal delta front, distal delta front, and prodelta) and open marine environments were identified for Qadir Member which is is under the impact of tidal currents. The chemical weathering index (71%) indicated semi-arid to semi-humid conditions and plotting the geochemical data showed the provenance of re-cycling and active continental margin and because of Chemical Index of Alteration, the weathering rate was found to be rather medium to high. The geochemical diagrams also showed a probable source of the intermediate igneous and sedimentary rocks. The active continental margin conditions for this deposit could suggest the Neotethys subduction under Iran’s plate and volcanic activity at the end of Triassic, which coincided with the early Cimmerian orogeny in Alborz and Central East Iranian Microcontinent.

scholarly journals Sandstone petrography and geochemistry of the Nayband Formation (Upper Triassic, Central Iran): Implications for sediment provenance and tectonic setting

2019 ◽  
Vol 112 (1) ◽  
pp. 20-41 ◽  
Author(s):  
Asghar Etesampour ◽  
Asadollah Mahboubi ◽  
Reza Moussavi-Harami ◽  
Nasser Arzani ◽  
Mohammad Ali Salehi
Keyword(s):  
Tectonic Setting ◽  
Active Continental Margin ◽  
Source Area ◽  
Major Elements ◽  
Upper Triassic ◽  
Late Triassic ◽  
Sediment Provenance ◽  
Provenance Areas ◽  
Nayband Formation ◽  
Southwestern Margin

AbstractThe Upper Triassic (Norian–Rhaetian) Nayband Formation is situated at the southwestern margin of Central East Iranian Microcontinent and records Eo-Cimmerian events. The formation is composed of mixed carbonate-siliciclastic deposits. This study presents information on the tectonic reconstruction and palaeoclimate of the southwestern margin of Central East Iranian Microcontinent during the Late Triassic. Petrography and modal analyses of sandstones show a variety of quartz-rich petrofacies including subarkose, lithic arkose, sublitharenite, feldspathic litharenite and litharenite. The combined modal analysis and geochemical results of major and trace elements of the sandstone samples represents mixed sedimentary, intermediate, felsic igneous rocks and moderate- to high-grade metamorphic provenance areas. The major elements and modal analyses of the Nayband Formation sandstone samples suggest an active continental margin tec-tonic settings. The palaeoclimatic conditions were sub-humid to humid with relatively low to moderate weathering in the source area which is in agreement with the palaeogeography and palaeotectonic history of southwestern margin of Central East Iranian Microcontinent during the Late Triassic.

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