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Acorn barnacles (Crustacea, Thoracica, Balanomorpha) from the Eocene and Oligocene of the Isle of Wight and Hampshire (United Kingdom) and Manche, northern France

Gale Andrew Scott

Acta Geologica Polonica

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2021

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Vol. 71, no. 2

153--174

EN

Balanomorph cirripedes from the Eocene–Oligocene of the Hampshire Basin (United Kingdom) and the Middle Eocene of the Cotentin Peninsula, Manche (France) are described. A new genus, Vectibalanus, is founded, with the type species Balanus unguiformis J. de C. Sowerby, 1846; assigned to this are also Balanus erisma J. de C. Sowerby, 1846 and Vectibalanus mortoni sp. nov. In addition, a new species of Lophobalanus Zullo, 1984, L. fresvillensis sp. nov., is described. This is the first record of that genus from outside the eastern USA and the oldest species known to date. Cladistic analysis of 24 morphological characters suggests that Vectibalanus unguiformis is sister taxon to a group comprising the most derived balanomorph taxa, and thus represents an important transition in the evolution of the group, with the initiation of development of a complex parietal wall structure. Vectibalanus unguiformis was evidently adapted to low salinity habitats (10-30 ppt), and is the oldest known brackish water barnacle. The other species (V. erisma, V. mortoni sp. nov.) occupied more clearly marine environments (>30 ppt). Balanomorph barnacles appeared simultaneously in the Priabonian (Upper Eocene) of the Gulf and Atlantic seaboards of the USA and northwest Europe, which probably represents a northerly migration from Tethys.

2

Episkeletozoans and bioerosional ichnotaxa on isolated bones of Late Cretaceous mosasaurs and cheloniid turtles from the Maastricht area, the Netherlands

Jagt John W.M., Deckers Mart J.M., De Leebeeck Magda, Donovan Stephen K., Nieuwenhuis Eric

Geologos

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2020

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Vol. 26, No. 1

39--49

EN

Isolated bones of three taxa of marine reptiles (Mosasaurus hoffmannii Mantell, Plioplatecarpus marshi Dollo and Allopleuron hofmanni (Gray)) from various levels within the Maastricht Formation (upper Maastrichtian) at the former ENCI-Heidelberg Cement Group quarry (Maastricht, the Netherlands) exhibit bioerosional traces and encrustation. Episkeletozoans include dimyid, ostreid and monopleurid bivalves, at least three species of cheilostome and cyclostome bryozoans and two adnate calcareous foraminifera. The bones show biting traces (Gnathichnus pentax Bromley, Linichnus cf. serratus Jacobsen & Bromley and Machichnus isp.), as well as borings. The latter may be referred to Karethraichnus lakkos Zonneveld, Bartels, Gunnell & McHugh, which is here considered to be a junior synonym of Gastrochaenolites isp.

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Basin-centered gas accumulations in Rotliegend Sandstones

Nosal J., Waliczek M.

Geology, Geophysics and Environment

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2014

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Vol. 40, no. 1

114--115

EN

Permian Rotliegend Sandstones are the most important gas reservoirs in north-west Europe (Gast et al. 2010). Those sandstones were deposited in playa, fluvial and aeolian depositional systems (Kiersnowski et al. 2010) and may host both conventional and unconventional deposits. The reservoirs are supplied in hydrocarbons by the Carboniferous sediments, lying directly beneath. Some of the unconventional accumulations may occur in conditions of Basin-Centered Gas System (BCGS). Basin-Centred Gas Accumulations (BCGAs), associated with BCGS, are gas-saturated, abnormally pressured, have a low-permeability reservoir and commonly lack of down-dip water contact (Law 2002). Two types BCGAs can be distinguished - direct and indirect, and they differ in the attributes of the system - the type of organic matter, thermal maturity, sealing and the distance of hydrocarbons migration. Direct Basin-Centered Gas Systems may occur in the area of the Polish part of the Permian Basin. The purpose of the present work was to indicate the Aeolian Permian Rotliegend sandstones as a reservoir rocks for direct Basin-Centered Gas Accumulations, according to the petrophysical properties and reflectance of vitrinite measurements. Analysis was performed on fifteen core samples located within the aeolian sediments of Eastern Erg (center of Polish part of Permian Basin) from the depth interval 3,559.3-4,275.9 m. Random reflectance of vitrinite was measured under oil immersion using Carl Zeiss Axioplan microscope in reflected monochromatic non-polarised light. Mean reflectance values were calculated for all measurement. Permeability measurements were done on plug-type samples (cylindrical with diameter 25.4 mm and length of between 20-40 mm. Plugs were drilled perpendicularto the cylinder axis. Values of average capillary diameter were obtained from porosimetric analysis on bulk samples with AutoPore 9220 mercury porosimeter. In each sample, the organic matter was dominated by vitrinite-like matter what could indicate humic organic matter typical for gas prone source rocks. The measured vitrinite reflectance values indicate that organic matter reached the maturation stages of hydrocarbon generation characteristic for the gas window phase (Ro > 2%). Values of average capillary diameter provedweak filtration. Permeability results shown typical values for tight sandstones from BCGS, lower then 0.1 mD. Analysis performed on aeolian Rotliegend sandstones from the area of Eastern Erg confirmed their potential as a reservoir rock for Basin-Centered Gas Accumulations. Humic type of organic matter and values vitrinite reflectance corresponding to gas window are specific for BSGAs. The analyzed samples of the aeolian Rotliegend sandstones are characterized by very low permeabillity, not exceeding 0.1 mD and slow flow rates, what determines capillary sealing of the accumulation. Short distance of hydrocarbons migration was confirmed by the location of Carboniferous source rocks. All those factors allow to classify the aeolian Rotliegend sandstones as a potential reservoir rock for Basin-Centered Gas Accumulations.

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Correlation of the Barremian belemnite successions of northwest Europe and the Ulyanovsk - Saratov area (Russian Platform)

Baraboshkin E. J., Mutterlose J.

Acta Geologica Polonica

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2004

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Vol. 54, no. 4

499-510

EN

The marine sedimentary successions of Barremian age yield, both in northwest Europe and on the Russian Platform, diverse and abundant belemnite faunas. These include the genera Praeoxyteuthis, Aulacoteuthis and Oxyteuthis and are attributed to the boreal belemnite family Oxyteuthididae. The Oxyteuthididae are endemic to northwest Europe (northern Germany, northeast England, North Sea) and the Russian Platform, where they evolved in isolation. They possibly derived from the belemnite genus Acroteuthis in Late Hauterivian time. Phylogenetically they are interpreted as the latest off shoot of the Belemnitina, which became extinct in the Early Aptian. Since ammonites are extremely rare on the Russian Platform oxyteuthid belemnites have been used to establish a biozonation scheme with seven belemnite zones (from bottom to top):Praeoxyteuthis hibolitiformis Zone (Early Barremian), Praeoxyteuthis jasikofiana Zone (Early Barremian), Praeoxyteuthis pugio Zone (earliest Barremian), Aulacoteuth is descendens Zone (late Early Barremian), Oxyteuthis brunsvicensis Zone (early Late Barremian), Oxyteuthis germanica Zone (Late Barremian), and Oxyteuthis lahuseni Zone (latest Barremian/Aptian). Apart from the O. lahuseni Zone this zonation can be correlated to the well established belemnite scheme of northwest Europe, allowing a detailed correlation of the Barremian of both areas.