The Shirokoe Place as a reference section of the upper Visean substage in the Upper Pechora basin (Unya river, Northern Urals)

Research subject. Carbonate rocks in the “Shirokoe Place” section (Unya River, Northern Urals). Material and methods. The work was based on a study of the composition and structural peculiarities of rocks and species diversities of forami- nifera and calcareous algae in the most important section of Upper Visean sediments in the lower reaches of the Unya river.Results. The rocks in the section are represented by bioclastic limestones, dolomites and various transition differences. The section features a wide presence of green Koninckopora, red Epistacheoides and Ungdarella algae. Less common are Palaeoberesella, Anthracoporella, Kamaena and Stacheoides. Fasciella is extremely rare, and Calcifolium is virtually absent. Foraminifera complexes are representative, but there are no zonal species Eostaffella tenebrosa (Venevsky horizon), genera Valvulinella (Tula horizon), Bradyina and Howchinia (Mikhailovsky and Venevsky horizons). Endothyranopsis, Janischewskina and Cribrospira are rare.Conclusions. The study of the species diversity of foraminifera and calcareous algae allowed us to clarify the stratigraphic division of the upper Visean sediments in the “Shirokoe Place” section. The Tula, Aleksinsky, Mikhailovsky and Venevsky horizons of the Upper Visean were reliably identified. The studied section can be used as a reference when creating stratigraphic schemes of Later Visean deposits for the Western subzone of the Upper Pechora transverse sinking of the Western folded zone of the Urals and adjacent areas of the PreUrals regional trough.

Foraminiferal biostratigraphy of Brigantian-Arnsbergian limestones from eastern Scotland and Northumberland (northeast England)

ABSTRACT Foraminifers, calcareous algae and incertae sedis Algospongia of late Asbian to late Brigantian age in limestones from East Fife, East Lothian and Northumberland, enable the base of the late Brigantian to be recognised in all these areas. Preservation of the late Asbian and early Brigantian limestones in cyclothemic successions is generally poor. The St Monans White Limestone (St Monans, Fife), First Abden Limestone (Kirkcaldy, Fife), Middle Longcraig Limestone (East Lothian) and Lower Bath-House Wood/Middle Bath-House Wood (Northumberland) were confidently correlated by their foraminiferal assemblages. These limestones are all assigned to the top of the Assemblage 6 in northern England (Single Post Limestone). The St Monans Brecciated/St Monans Little/Charlestown Main limestones (St Monans, Fife) and the Second Abden/Seafield Tower limestones (Kirkcaldy, Fife), Upper Longcraig/Lower Skateraw limestones (East Lothian), Upper Bath-House Wood/Shotto Wood limestones and Eelwell Limestone (Northumberland) are assigned to the Assemblage 7 in northern England (Scar Limestone and Five Yard Limestone). The paired Middle/Upper Skateraw limestones (East Lothian) and the Acre Limestone (Northumberland) contain representatives of the Assemblage 8 from northern England (Three Yard Limestone). Higher up in the succession, in Northumberland, the foraminiferal assemblage in the Sandbanks Limestone can be compared with Assemblage 9 in northern England (Four Fathom Limestone). Above the Great Limestone and Little Limestone, with their characteristic Pendleian assemblages, the Sugar Sands Limestone and Corbridge Limestone contain Arnsbergian foraminiferal assemblages, typical of the Lower Felltop Limestone in northern England. The Lower Foxton Limestone is correlated with the Upper Felltop Limestone, whereas the Thornbrough Limestone in Northumberland lacks diagnostic Arnsbergian taxa.

Microbial-, fusulinid limestones with large gastropods and calcareous algae: an unusual facies from the Early Permian Khao Khad Formation of Central Thailand

The Early Permian (Kungurian) Khao Khad Formation of Central Thailand consists mostly of carbonates deposited on the western margin of the Indochina Terrane. This formation has yielded unusual microbial-fusulinid limestones with large gastropods which contribute most to the rock volume. With a height of more than 6 cm, the gastropods are amongst the largest Early Permian gastropods ever reported. Gastropods as major rock formers are rare in the Palaeozoic. This, and other recently reported invertebrate faunas from Thailand show that gastropods may dominate Permian fossil assemblages not only in diversity, but also regarding abundance and in some cases also regarding biomass. Besides gastropods, fusulinids, various calcareous algae, intraclasts and thick microbial-cyanobacterial (Girvanella and Archaeolithoporella) coatings and reticular microbial patches as well as thick inter- and intragranular radial fibrous cement crusts are present. The gastropods represent at least four species and belong probably to undescribed taxa. The fusulinid genus Pseudofusulina and Misellina (M.) termieri are reported from the Khao Khad Formation for the first time and indicate a Bolorian age. Calcareous algae are dominated by dasycladaceans followed by gymnocodiaceans and solenoporaceans. The studied limestone almost completely lacks metazoan reef builders such as corals and sponges. Likewise, brachiopods and bivalves are absent in the studied samples and echinoderms are very scarce. The carbonate is interpreted as product of shallow water, back-reef lagoonal platform community with a high productivity providing the large gastropods with sufficient food. However, conditions were too eutrophic for sessile filter feeders including metazoan reef builders.

A New Preparation Method of Microfauna from Gypsum: Micropaleontological Association from the Middle Miocene Badenian Gypsum Deposits of Paratethys

Evaporitic gypsum deposits represent an important paleoenvironmental record of the Miocene Badenian of the Carpathian Mountains belt. In this study, we developed a nontoxic method to concentrate calcareous microfossils from gypsum (CaSO4·2H2O), by treating the sulfate with ammonium acetate. We applied the newly developed method to gypsum collected from the Evaporitic Formation outcropping northward of Slănic-Prahova in the Eastern Carpathians. For the first time for this formation, we describe a calcareous microfossil assemblage characterized by the presence of planktonic foraminifera as well as cysts and fragments of calcareous algae.