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Integrated microfacies, macrobenthos and trace-fossil analysis of the lower‒middle Miocene succession of Gebel Gharra, Cairo-Suez District, Egypt

Mandor Mona, El Hedeny Magdy, El-Sabbagh Ahmed, Nagm Emad, Abdelaal Abdelaal, Rashwan Mohamed, Mansour Heba

Annales Societatis Geologorum Poloniae

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2023

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Vol. 93, No. 4

381--409

EN

The palaeoecology and palaeoenvironments of the lower–middle Miocene succession in Gebel Gharra, NW of Suez, Egypt, are interpreted, on the basis of a detailed study of microfacies, trace fossils, and macrofaunal benthic assemblages. This succession consists of a lower siliciclastic part (the Gharra Formation) and a carbonate-dominated upper part (the Geniefa Formation), corresponding to a general transgression-regression cycle. Facies characteristics indicate depositional palaeoenvironments, ranging from supratidal, lagoonal, to shoal settings on an inner ramp that was influenced proximally by clastic input. At least seven ichnotaxa were recorded in the lower Miocene Gharra Formation, representing suites of the Skolithos ichnofacies. Among them, the ichnogenus Polykladichnus is recorded for the first time in Egypt. The macrobenthic taxa identified in 13 statistical samples are grouped into five assemblages (A–E) that are described and interpreted as the remains of communities. The faunal distribution and trophic structure of most of these assemblages confirm the existence of relatively stable and low-stress conditions. However, the trophic structure of the assemblages reflects the influence of particular environmental parameters, the dissolution of aragonitic shells and/or sample-size effects. Environmental parameters, controlling the distribution of trace and/or body fossils, include substrate consistency, bathymetry, water energy, productivity level, rate of sedimentation, salinity, and oxygen availability. The results of integrated lithoand biofacies analysis confirm that the succession studied was deposited in different environmental settings, providing perfect conditions for the occurrence and preservation of trace-fossil and macrobenthos assemblages.

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Gastropods [Trochoidea: Trochidae Rafinesque, 1815 and Calliostomatidae Thiele, 1924 (1847)] from the middle Miocene of Ukraine, Central Paratethys

Nosowska Ewa

Acta Geologica Polonica

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2020

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Vol. 70, no. 4

453--528

EN

Over three thousand specimens representing the superfamily Trochoidea Rafinesque, 1815 [Trochidae Rafinesque, 1815 and Calliostomatidae Thiele, 1924 (1847)] from the upper Upper Badenian = Kosovian = lower Serra vallian (middle Miocene) marine deposits of Ukraine, housed in the collections of the Polish Academy of Sciences Museum of the Earth in Warsaw (MZ), are studied herein. The abundant material has allowed for investigations of the intraspecific variation and revision of earlier determinations. As a result, 21 species belonging to 5 genera have been identified, described and illustrated, of which one is new [Clanculus (Clanculopsis) krachi sp. nov.] and one is left in open nomenclature. Granulifera O. Anistratenko, 2000 is considered a junior subjective synonym of Clanculopsis Monterosato, 1879; Granulifera pulla O. Anistratenko, 2000 is considered a junior subjective synonym of Monodonta tuberculata Eichwald, 1830; Gibbula sytovae Amitrov, 1961 is considered a junior subjective synonym of Trochus miocaenicus Mayer, 1853; Gibbula volhynica Friedberg, 1928 is considered a junior subjective synonym of Trochus novemcinctus von Buch, 1830; and Trochus buchii du Bois de Montpéreux, 1831 is suppressed in favour of the senior subjective synonym Trochus puschii Andrzejowski, 1830. The geographic distribution and stratigraphic ranges of the taxa are given. Six species are known only from the Polish-Ukrainian part of the Fore-Carpathian Basin. The protoconch features are systematically studied in the Trochidae and Calliostomatidae from this area for the first time.

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Badenian (middle Miocene) decapod crustaceans from western Ukraine, with remarks on eco-taphonomy, palaeoecology and biogeography

Górka M.

Acta Geologica Polonica

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2018

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Vol. 68, no. 4

511–-535

EN

The decapod fauna from the Badenian (middle Miocene) deposits of western Ukraine comprises in total 31 taxa: 20 species, 9 taxa left in open nomenclature, and 2 determined at family level. Thirteen of these taxa are reported for the first time from the territory of Ukraine. Among them are the first records of Trapezia glaessneri Müller, 1976 in the Fore-Carpathian Basin and Pachycheles sp. in Paratethys. One taxon (Petrolisthes sp. A) probably represents a new species. The occurrence of this significant decapod fauna is restricted almost exclusively to the Upper Badenian (i.e., early Serravallian) coralgal reefs of the Ternopil Beds. The taxonomic composition of the decapods indicates that the Late Badenian depositional environment was a shallow marine basin dominated by reefs that developed in warm-to-tropical waters of oceanic salinity. The decapod assemblage from the Ternopil Beds is similar in its taxonomic composition to numerous decapod faunules from fossil reefs of Eocene to Miocene age from the Mediterranean realm and of Miocene age from Paratethys. In contrast, decapod remains are very scarce in Badenian siliciclastic deposits (Mikolaiv Beds) and are represented by the most resistant skeletal elements, i.e., dactyli and fixed fingers. This scarcity was caused by the high-energy environment, with frequent episodes of redeposition, which disintegrated and abraded the decapod remains. The decapod fauna from the Badenian (middle Miocene) deposits of western Ukraine comprises in total 31 taxa: 20 species, 9 taxa left in open nomenclature, and 2 determined at family level. Thirteen of these taxa are reported for the first time from the territory of Ukraine. Among them are the first records of Trapezia glaessneri Müller, 1976 in the Fore-Carpathian Basin and Pachycheles sp. in Paratethys. One taxon (Petrolisthes sp. A) probably represents a new species. The occurrence of this significant decapod fauna is restricted almost exclusively to the Upper Badenian (i.e., early Serravallian) coralgal reefs of the Ternopil Beds. The taxonomic composition of the decapods indicates that the Late Badenian depositional environment was a shallow marine basin dominated by reefs that developed in warm-to-tropical waters of oceanic salinity. The decapod assemblage from the Ternopil Beds is similar in its taxonomic composition to numerous decapod faunules from fossil reefs of Eocene to Miocene age from the Mediterranean realm and of Miocene age from Paratethys. In contrast, decapod remains are very scarce in Badenian siliciclastic deposits (Mikolaiv Beds) and are represented by the most resistant skeletal elements, i.e., dactyli and fixed fingers. This scarcity was caused by the high-energy environment, with frequent episodes of redeposition, which disintegrated and abraded the decapod remains.

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A new look at the bivalve Anomia ephippium Linnæus, 1758 from the Miocene of the Central Paratethys: anexample from the Nowy Sącz Basin in Poland

Studencka B.

Acta Geologica Polonica

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2018

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Vol. 68, no. 4

635--650

EN

For the first time, articulated shells of Anomia ephippium Linnæus, 1758, the bivalve species widely distributed in the Egerian–Late Badenian (latest early Oligocene to late middle Miocene) in the Central Paratethys, are described and illustrated. The most astonishing fact is the presence of a heavily calcified byssus that anchored the animal to hard substrates, which is still preserved inside the byssal notch. The investigated material derives from the Badenian (middle Miocene) Niskowa Formation in the Nowy Sącz Basin, a small intramontane basin situated in the Polish Outer Carpathians. Apart from articulated shells and left valves, the collected material contains some dozen of calcified byssi fixed to rigid substrate, SEM images of which are presented. Examination of the A. ephippium specimens stored in the Polish Academy of Sciences, Museum of the Earth in Warsaw revealed other Paratethyan records of anomiid calcified byssi attached to other specimens of A. ephippium. Finally, the paper provides an overview of the previous studies on the representatives of the genus Anomia Linnæus, 1758 from the Central Paratethys and its specific assignment.

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A new heterobranch gastropod, Chelidonura radwanskii sp. nov., from the middle Miocene of the Korytnica Basin (Holy Cross Mountains, Poland)

Bałuk W.

Acta Geologica Polonica

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2018

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Vol. 68, no. 4

499--502

EN

A new species of heterobranch gastropods, the hammerhead Chelidonura radwanskii sp. nov., found in the socalled Pleurotoma-clays of middle Miocene (Langhian) age in the environs of Korytnica, southern Holy Cross Mountains, Poland, is described. It is the first fossil representative of Chelidonura A. Adams, 1850. This tiny gastropod is named in honour of the late Professor Andrzej Radwański.

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A commensal relationship between alpheid crustaceans and gobiid fish in the middle Miocene of southern Poland (Central Paratethys)

Radwańska U.

Acta Geologica Polonica

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2018

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Vol. 68, no. 4

597--605

EN

Remains of decapod crustaceans of the family Alpheidae Rafinesque, 1815 and bony fish of the family Gobiidae Bonaparte, 1832 co-occur at a number of localities in the Korytnica Basin (Holy Cross Mountains) and in a newly exposed section along a stream near Niskowa (Outer Carpathians), both in southern Poland. These remains (alpheid major right-sided cheliped tips and gobiid otoliths) are interpreted as documenting a commensal partnership that existed in the shallowest zones of the middle Miocene Fore-Carpathian Basin in southern Poland under environmental conditions that must have been comparable to those of the present-day tropical/ subtropical Indo-West Pacific and Caribbean.