Articles
Journal of Palaeogeography (20953836)14(2)pp. 535-558
The investigation mainly focuses on larger benthic foraminifera, Canalispina, Siderolites, Loftusia, and Omphalocyclus from the Maastrichtian deposits (Tarbur Formation) in the Zagros Foreland Basin. The four new species: Canalispina zagrosia sp. nov., Siderolites persica sp. nov., Loftusia tarburica sp. nov., and Omphalocyclus tarburensis sp. nov., and four other index species: Siderolites calcitrapoides, Omphalocyclus cideensis, O. macroporus, and Loftusia baykali were identified. L. harrisoni is thought to be ancestor of L. minor, L. arabica, L. matsumarui, L. tarburica sp. nov., L. occidentalis, L. coxi, L. baykali, L. kahtaensis and L. oktayi during the early, middle and late Maastrichtian, while L. persica and L. elongata evolved into L. arabica in the middle Maastrichtian. L. turcica and L. morgani are close forms of L. elongata in the middle and late Maastrichtian, and L. anatolica and L. morgani are the predominant forms in the late Maastrichtian. The wall structures of Loftusia species are more complex in the late Maastrichtian than in early Maastrichtian forms due to evolutionary trends. Loftusia species with numerous whorls were predominant in the middle Maastrichtian. In contrast to this, the species with low whorl numbers during the early and late Maastrichtian were dominant. Detailed studies on Omphalocyclus species indicate that (1) the genus Omphalocyclus migrated from the middle part of the Tethys to other Tethyan areas during the late Campanian, and (2) the diversity of Omphalocyclus species of eastern Tethys (North African part) was higher than in other areas. © 2025 The Author(s)
Journal of Earth Science (1867111X)35(5)pp. 1527-1545
A sedimentological investigation was carried out to reconstruct the paleogeography of the Zagros Foreland Basin. Based on the study of more than 1 000 rock samples, nine carbonate microfacies and three terrigenous facies were identified. The study reveals that the Maastrichtian succession was deposited in a widespread homoclinal ramp in the High Zagros Basin. Three (Gandom Kar area), two (Ardal area), seven (Gardbishe area), five (Shirmard area), two (Kuh-e-Kamaneh area), three (Kuh-e-Balghar area), and six (Murak area) of depositional sequences (3rd order) were identified. The thickness of the lowstand systems tract (LST) due to activities of local faults and subsidence in the southeast is more than in the central and northwest of the High Zagros Basin during the Early and Early Middle Maastrichtian. During the Middle Maastrichtian, the shallow and deep marine deposits were formed during the transgressive systems tract (TST) and highstand systems tract (HST) in this basin and the rate of subsidence in the center of this basin (Gardbishe area) is higher than in other areas and the platform was drowned in this area. The falling relative sea-level due to activities of local faults led to that marine deposits were absent in all parts of the High Zagros Basin (except the south part) during the Late Maastrichtian. Paleogeographical studies on the Zagros Basin during the Late Campanian–Maastrichtian showed the following results: shallow marine environments were developed in the south-east of this basin, and the turbidite, delta, and fluvial environments in the northwest were developed more than in other areas. © China University of Geosciences (Wuhan) and Springer-Verlag GmbH Germany, Part of Springer Nature 2024.
Schlagintweit, F.,
Omidvar, M.,
Safari, A.,
Yazdi-moghadam, M.,
Rashidi, K. Rivista Italiana di Paleontologia e Stratigrafia (20394942)130(3)pp. 487-506
New data (onshore, offshore) on the Upper Cretaceous Ilam Formation of southwestern Iran are provided concerning the common presence of dasycladalean green algae (families Triploporellaceae, Polyphysaceae) that have so far been treated mostly in open nomenclature. The assemblage consists of the five taxa Salpingoporella ubaiydhi Radoičić, 1979, Dissocladella ondulata (Raineri, 1922), Trinocladus tripolitanus Raineri, 1922, Clypeina cf. dusanbrstinai Radoičić, 1997, and gen. et sp. indet. The taxa typically prevail in wackestones-packstones but exhibit different distributional patterns. While S. ubaiydhi and T. tripolitanus, rarely associated with D. ondulata, form a characteristic assemblage in a distal infralittoral facies (more diverse assemblage; zone no. 31 of Wynd, 1965), C. cf. dusanbrstinai occurs in a proximal infralittoral facies associated with miliolids among also complex forms (rhapydioninids) (assemblage zone no. 30 of Wynd, 1965). It is concluded that the two assemblage zones refer to different palaeoenvironments, instead of different ages (‘lower’ and ‘upper’). Based on benthic foraminifera, the main part of the Ilam Formation can be ascribed to the Santonian. For the lower part, a late Coniacian age is suggested implied indirectly by the comparably long vertical range of the rotaliid Orbitokathina vonderschmitti Hottinger, 1966 of the studied core. This would be in conformity with the K 150 Arabian Plate K 150 sequence boundary referring to a late Turonian?–early Coniacian hiatus. From a palaeobiogeographic perspective, T. tripolitanus is a cosmopolitan species, S. ubaiydhi is restricted to the area of the former Arabian Plate (subsurface Iraq, Saudi Arabia and Egypt), while C. dusanbrstinai has been recorded only from Serbia (type-locality). In addition to the algae, the stratigraphic discussion includes the occurrence of the benthic foraminifera Reticulinella? kaeveri Cherchi, Radoičić & Schroeder, 1989 and Orbitoides mid-orientalis (Eames & Smout, 1956) in the Ilam Formation. © 2024 Universita degli Studi di Milano. All rights reserved.