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Brachiopods from the Lower Red Formation (Lower Oligocene) of the Isfahan Province, Central Iran

Bitner Maria Aleksandra, Bahrami Ali, Yazdi Mehdi, Zágoršek Kamil

Annales Societatis Geologorum Poloniae

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2023

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Vol. 93, No. 4

411--422

EN

The study presents the first record of Early Oligocene brachiopods from the Lower Red Formation of the Isfahan Province, Central Iran. The assemblage comprises six brachiopod taxa, belonging to five genera, Novocrania Lee and Brunton, Thecidellina Thomson, Argyrotheca Dall, Joania Álvarez, Brunton and Long, and Platidia Costa. Two species are described as new, Thecidellina persica sp. nov. and Argyrotheca ramshehensis sp. nov. The discovery of Thecidellina in Iran is the first confirmed occurrence of this genus in Oligocene deposits, filling the gap between known Eocene and Miocene occurrences. At the species level, the brachiopods investigated here show no affinity to those from the Lower Miocene Qom Formation.

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Oligocene crabs (Decapoda: Brachyura) from the Asmari Formation in Yasuj area (SW Iran)

Bahrami Ali, Ossó Alex, Yazdi Mehdi, Ansari Heshmatollah

Acta Geologica Polonica

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2023

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Vol. 73, no. 2

189--200

EN

New findings of crustacean decapod brachyurans from the Rupelian period (lower Oligocene) in Iran are presented in this study. In particular, Lophoranina sp. and Palaeocarpilius cf. P. rugifer Stoliczka, 1871, from the Rupelian strata were found in two previously unexplored localities, Abshar and Vezg near Yasuj in the southwestern region of Iran. The discovery contributes to fill the gap in the record of brachyuran decapod crustaceans in Iran during the Eocene and Miocene periods. The presence of both genera in the Oligocene of Iran suggests a certain degree of faunal similarity among brachyurans on both sides of the Tethys Realm.

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Early Oligocene brachiopods from the rocky-shore deposits at Mammendorf, central Germany

Bitner Maria Aleksandra, Müller Arnold

Annales Societatis Geologorum Poloniae

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2022

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Vol. 92, No. 1

87--107

EN

Thirteen species, belonging to eleven genera, i.e., Discinisca Dall, Novocrania Lee and Brunton, Lacazella Munier-Chalmas, Pliothyrina van Roy, Terebratulina d’Orbigny, Megathiris d’Orbigny, Argyrotheca Dall, Bronnothyris Popiel-Barczyk and Smirnova, Joania Álvarez, Brunton and Long, Platidia Costa and Megerlia King, have been identified in the lower Oligocene rocky-shore deposits at Mammendorf, central Germany. The occurrence of the species Discinisca fallens (Wood), Argyrotheca bitnerae Dulai and Megerlia truncata (Linnaeus) extends their stratigraphic range back to the early Oligocene. The affinity to the early Oligocene brachiopod fauna of the Mainz Basin is noted.

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Oligocene bivalve faunas from the Silesian Nappe, Polish Outer Carpathians: Evidence for the early history of the Paratethys

Studencka B., Popov S., Bieńkowska-Wasiluk M., Wasiluk R.

Geological Quarterly

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2016

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Vol. 60, No. 2

317--340

EN

The study is focused on the taxonomic inventory of an intriguing bivalve fauna from the Lower Oligocene Menilite Beds (Dynów Marls) within the Silesian Nappe, Polish Outer Carpathians. Sixteen bivalve species have been identified within the material collected in two small quarries in Jabłonica Polska near Krosno. Stratigraphic and geographic distributions of all recognized species are considered. This assemblage, the first of this kind in Poland and one of three recognized in the Outer Carpathians, shows clear affinities to coeval typical Solenovian faunas from Ukraine to Kazakhstan, with particular comparison made to bivalve faunas from the Menilite Formation (Subchert Member) within the Boryslav-Pokuttya Nappe, Ukrainian Outer Carpathians. Moreover, this study presents an overview of the main aspects and definitions of the date of the Paratethys origin. The main criterion used to define the time of the Paratethys birth is the distinct faunal turnover from the moderately diverse boreal or Tethyan bivalve faunas populating particular basins of the Northern Peri-Tethys in the earliest Oligocene to the uniform, highly endemic fauna inhabiting the newly formed semi-closed basin. This vast inland sea, named Paratethys, was populated by representatives of eight euryhaline bivalve families. They are characterized by extinct Paratethyan genera, such as Bessia Kojumdgieva et Sapungieva, Merklinicardium Popov, Korobkoviella Merklin, Urbnisia Goncharova, Ergenica G. Popov and Janschinella Merklin.

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Sedimentary conditions in the Siary zone of the Magura basin (Carpathians) in the late Eocene-early Oligocene

Leszczyński S., Malata E.

Annales Societatis Geologorum Poloniae

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2002

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Vol. 72, No 3

201-239

EN

The sediments of the upper Eocene (Priabonian)-lower Oligocene (Rupelian) of the Siary zone in the Magura nappe (basically Magura Beds in glauconitic facies) display features indicating their origination in sedimentary conditions quite different from those in which coeval sediments from the other parts of the Carpathians were deposited. This paper aims at interpreting the sedimentary conditions on the basis of lithofacies, their vertical and lateral distribution, foraminifera assemblages, CaCO3 and organic matter content determined in six transects through the entire Siary zone, the contents of main and trace elements determined in 11 samples from one section and different published data. Lithofacies and the present day shape of the Siary zone suggest sedimentation of the entire succession in a strongly elongated confined basin. Facies distribution indicates deposition on a submarine ramp that gradually expanded to NE and E along the slopes of the outer basin margin. Assemblages of foraminifera suggest location of the basin bottom below the foraminiferal lysocline. Moreover, foraminifera together with bioturbation structures and sediment geochemistry indicate sedimentation mainly in weakly oxic, close to dysoxic bottom waters. The differences in facies in relation to the coeval deposits of the other parts of the Carpathians are interpreted as resulting mainly from intense resedimentation in the Siary zone during the Priabonian-Rupelian, and in part from the relatively low calcium carbonate supply. Gradual expansion of resedimentation towards NE, followed by a decrease in the supply of coarse-grained material is regarded as due to lithosphere rollback beneath the evolving Carpathians. This process is interpreted as of superior significance in controlling sedimentation during the Priabonian-Rupelian not only in the Siary zone but also in the entire Magura basin. This was the factor responsible for forcing the subsidence of the Magura basin, accretionary wedge development in its inner part, and fore-bulging of the area at some distance in front of the zone of the rolling back lithosphere, i.e. in the source area of the sedimentary succession in question. Finally, this process also caused drowning and burying of the source area.