Permian smaller foraminifers: taxonomy, biostratigraphy and biogeography

2016 ◽  
Vol 450 (1) ◽  
pp. 205-252 ◽  
Author(s):  
Daniel Vachard
Keyword(s):  
2019 ◽  
Vol 94 (2) ◽  
pp. 202-216
Author(s):  
Valerio Gennari ◽  
Roberto Rettori

AbstractAmong Permian smaller foraminifers, the genus Dagmarita is one of the most studied due to its worldwide distribution. The detailed study of the Zal (NW Iran) and Abadeh (Central Iran) stratigraphic sections led to redescription of the genus Dagmarita and its taxonomic composition. In Dagmarita, a peculiar generic morphological character, represented by a secondary valvular projection, has been detected for the first time among globivalvulinid foraminifers. The phylogeny of Dagmarita, and in particular its ancestor Sengoerina, is discussed and the new species, D. ghorbanii n. sp. and D. zalensis n. sp., are introduced. Analogies and differences among all the species belonging to Dagmarita are highlighted and morphological features of the new taxa are shown in 3D reconstructions, useful for understanding differently oriented sections of the specimens in thin section.UUID: http://zoobank.org/3d8eb14c-7757-4cbd-877c-4bacd2d156da


2012 ◽  
Vol 48 (4) ◽  
pp. 385-402 ◽  
Author(s):  
Zohreh Alipour ◽  
Seyyed Mahmood Hosseini-Nezhad ◽  
Daniel Vachard ◽  
Koorosh Rashidi

GeoArabia ◽  
2005 ◽  
Vol 10 (4) ◽  
pp. 77-134 ◽  
Author(s):  
Denis Vaslet ◽  
Yves-Michel Le Nindre ◽  
Daniel Vachard ◽  
Jean Broutin ◽  
Sylvie Crasquin-Soleau ◽  
...  

ABSTRACT The Permian-Triassic Khuff Formation crops out in central Saudi Arabia along a N-S belt, some 1,200 km in length. It is 171.4 m (562.2 ft) thick in the type section and divided into five members; from oldest to youngest: Ash Shiqqah (formerly Unayzah member of the Khuff Formation), Huqayl, Duhaysan, Midhnab and Khartam. The base of the Khuff Formation is recognised as a regional unconformity (Pre-Khuff Unconformity), and the top of the formation is defined by the conformable contact with the overlying Sudair Shale. The Ash Shiqqah Member is tentatively dated as ?Middle Permian ?Capitanian (?Midian) based on the presence of the fusulinids Monodiexodina kattaensis and Reichelina sp. The Huqayl Member is tentatively dated as ?Late Permian ?Wuchiapingian (?Dzhulfian) based on an assemblage of smaller foraminifers dominated by Pseudomidiella cf. labensis, Earlandia? spp. and Neodiscus aff. qinglongensis. The Duhaysan Member is dated as Late Permian (Wuchiapingian-Changhsingian) based on Hemigordius baoqingensis, Graecodiscus cf. kotlyarae, “Dentalina” hoi, and Colaniella cf. minuta. The sMidhnab Member is dated as Changhsingian (Dorashamian) based on Paradagmarita sp. and “Glomospirella spirillinoides” and the disappearance of the genera Nankinella and Globivalvulina. Within the continental facies in the upper part of the Midhnab Member, incised channels facies yielded the Late Permian Midhnab Flora. The Lower Khartam Member is also dated as latest Permian (Dorashamian) based on the presence of several species of Paradagmarita and “Nodosaria” dzhulfensis in the lowest beds of the member, and the ostracods Paraparchites spp., Knoxiella spp. and Kloedenellitina sp. throughout the Lower Khartam Member. The Upper Khartam Member is assigned to an Early Triassic (‘Scythian’) age based on the occurrence of the characteristic annelid Spirorbis phlyctaena. The Khuff Formation, in central Saudi Arabian outcrops, consists of four regional depositional sequences (DS PKh, DS PKm, DS PKk and DS TrS), each containing a maximum flooding interval (MFI, with the same designation). The oldest sequence DS PKh (named after Permian-Khuff-Huqayl) consists of the Ash Shiqqah and overlying Huqayl members. The basal sequence boundary corresponds to the Pre-Khuff Unconformity (PKU) and represents the onset of the first Permian flooding event recorded in the outcrops of Saudi Arabia. The massive gypsum, gypsiferous claystone, and solution breccias in the Ash Shiqqah Member are correlated to the subsurface Khuff-D Anhydrite. The MFI PKh is positioned in the basal part of the Huqayl Member, and is followed by the regressive evaporitic palaeoenvironments of the Huqayl Member. The DS PKm (named after Permian-Khuff-Midhnab) starts with the subtidal to littoral deposits of the Duhaysan Member, over an erosive surface upon DS PKh; and ends with the regressive supratidal to continental deposits at the upper part of the Midhnab Member. The MFI PKm is located at the base of the Midhnab Member, where limestones yielded an abundant marine fauna including cephalopods and brachiopods. The terminal Permian DS PKk (Permian-Khuff-Khartam) corresponds to the Lower Khartam Member. The basal SB PKk is marked by a return to marine subtidal conditions after the continental break at the end of DS PKm. The MFI PKk is characterised by marine fauna including abundant Permian ostracods, bactritids, and locally cephalopods. The DS TrS (named after the Sudair Shale Formation) starts with the littoral, tidal to intertidal deposits of the Early Triassic Upper Khartam Member of the Khuff Formation, and ends with the closed basin, clayey to evaporitic rocks of the Early Triassic Sudair Shale.


2014 ◽  
Vol 8 (5) ◽  
pp. 3119-3127 ◽  
Author(s):  
Hamed Yarahmadzahi ◽  
Daniel Vachard ◽  
Mohammad Nabi Gorgij

2019 ◽  
Vol 49 (2) ◽  
pp. 107-130 ◽  
Author(s):  
Hamed Yarahmadzahi ◽  
Daniel Vachard

Abstract Carboniferous and Permian strata crop out in Central Iran. The Asad-Abad section has yielded Gzhelian and Asselian fusulinid levels. Here we describe the smaller foraminifers of this section for the first time and introduce four biozones based on these taxa. Biozone I with Monotaxinoides? melanogaster n. sp. is interpreted to be early?-middle? Gzhelian in age (with possible reworkings affecting up to Moscovian/Kasimovian? levels) based upon the principle of superposition and of previous datings of the underlying series, but in the absence of direct datings by fusulinids of this lowermost part of the section. Further, Monotaxinoides? are generally known in the Bashkirian-Moscovian. Biozone II includes Raphconilia spp., Protonodosaria spp., and Rectogordius? minimus n. sp. and is interpreted as middle?-late Gzhelian in age. Biozone III includes Turrispiroides spp., Calcivertella anguinea, Calcitornella heathi, and Vervilleina crescenticamerata n. sp., and we base its early Asselian age on associated fusulinids. Finally, Biozone IV includes Cribrogenerina? sp. and Nodosinelloides longissima; its middle to late Asselian age, based on fusulinids, is confirmed by associated smaller foraminifers. The foraminiferal assemblages display marked differences in composition and stratigraphic distribution compared with those of Alborz and Tabas Block. Principally, they have unexpected similarities with several North American assemblages, especially the three new species: Monotaxinoides? melanogaster n. sp., Rectogordius? minimus n. sp., and Vervilleina crescenticamerata n. sp.


2015 ◽  
Vol 23 (4) ◽  
pp. 375-386
Author(s):  
T. V. Filimonova ◽  
M. N. Gorgij ◽  
H. Yarahmadzahi ◽  
E. Ja. Leven

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