Temat: carbon isotopes - Katalog OPAC zbiorów

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Tytuł:: Foraminiferal colonization related to the Zechstein (Lopingian) transgression in the western part of the Wolsztyn Palaeo-Ridge area, Western Poland
Autorzy:: Peryt, D.
Peryt, T. M.
Raczyński, P.
Chłódek, K.
Powiązania:: https://bibliotekanauki.pl/articles/2059413.pdf
Data publikacji:: 2012
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: Upper Permian
Zechstein
encrusting foraminifers
carbon isotopes
oxygen isotopes
transgression
breccias
Opis:: The basal Zechstein succession in SW Poland is dominated by breccias and/or conglomerates or extraclast-bearing bioclastic limestones, which were deposited during rapid flooding of the pre-existing intracontinental basin in the early Lopingian (Late Permian). Of these, the boulder-cobble breccias and conglomerates are interpreted as deposited in a rocky shore-zone where density flows and upwelling prevailed. The breccias gradually pass up into bryozoan (or other bioclastics) grainstones. The matrix-supported breccias were deposited as large extraclasts and blocks of Carboniferous rock were rolled down or detached from a cliff and were then either embedded into a carbonate sand or formed a framework supplying voids that could be colonized by tubular encrusting foraminifers. These foraminifers abound in all basal Zechstein facies (except in the debris-flow deposits) and are attributed to Palaeonubecularia. The associated faunas include other foraminifers (uniserial and hemigordiopsids), bryozoans, brachiopods, bivalves, gastropods, and microbial deposits. The prolific growth of tubular encrusting foraminifers has resulted from nutrient supply from the basin by upwelling. Botryoidal aragonite cements (also interpreted as due to upwelling) also characterize the basal Zechstein strata, although they were previously reported only from the upper Zechstein Limestone. The ẟI3C values of the basal Zechstein deposits show small variation and oscillated around 4.0%o, suggesting that these deposits are younger than the Kupferschiefer.
Źródło:: Geological Quarterly; 2012, 56, 3; 529--546
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Sedimentary history and biota of the Zechstein Limestone (Permian, Wuchiapingian) of the Jabłonna Reef in Western Poland
Autorzy:: Peryt, T. M.
Raczyński, P.
Peryt, D.
Chłódek, K.
Mikołajewski, K.
Powiązania:: https://bibliotekanauki.pl/articles/191254.pdf
Data publikacji:: 2016
Wydawca:: Polskie Towarzystwo Geologiczne
Tematy:: Wuchiapingian
reefs
Zechstein
bryozoans
stromatolites
aragonite cementation
neptunian dykes
carbon and oxygen isotopes
Opis:: The Jabłonna Reef, one of the reefs formed in Wuchiapingian time in the western part of the Wolsztyn palaeo-High (SW Poland), is characterized by quite irregular outlines and consists of three separate reef bodies (ca. 0.5–1.5 km² each; the thickness of the reef complex is usually >60 m). It is penetrated by four boreholes, which show two distinct phases of bryozoan reef development during deposition of the the Zechstein Limestone. The first one occurred early in the depositional history and botryoidal aragonitic cementation played a very important role in reef formation. This phase of bryozoan reef development terminated suddenly; one possible reason was that a relative change of sea level – first a fall and then a rise – disturbed the upwelling circulation. Consequently, bioclastic deposition predominated for a relatively long time until the second phase of bryozoan reef development occurred, but the latter was not accompanied by dubious early cementation. During this second phase, reticular fenestellid bryozoans were predominant. Subsequently, microbial reefs developed and abound in the upper part of the Zechstein Limestone sections. The general shallowing-upward nature of deposition in the Jab³onna Reef area resulted in reef-flat conditions with ubiquitous, microbial deposits, in the central part of the Jab³onna Reef. Then, the reef-flat started to prograde and eventually the entire Jab³onna Reef area became the site of very shallow, subaqueous deposition. Five biofacies are distinguished in the Jab³onna Reef sections: the Acanthocladia biofacies at the base, then mollusc-crinoid, brachiopod-bryozoan, Rectifenestella and at the top, stromatolite biofacies. They represent a shallowing-upward cycle, possibly with some important fluctuation recorded as the distinctive lithofacies boundary, corresponding to the Acanthocladia/mollusc-crinoid biofacies boundary. The 13C curves of the Jab³onna 2 and Jab³onna 4 boreholes permit correlation of the trends in the middle parts of both sections and confirm the strong diachroneity of the biofacies boundaries, with the exception of the roughly isochronous Acanthocladia/ mollusc-crinoid biofacies boundary. The presence of echinoderms and strophomenid brachiopods indicates that until deposition of the lower part of the Rectifenestella biofacies, conditions were clearly stenohaline. The subsequent elimination of stenohaline organisms and progressively poorer taxonomic differentiation of the faunal assemblage are characteristic for a slight, gradual rise in salinity. The taxonomic composition of organisms forming the Jab³onna Reef shows a similarity to reefs described from England and Germany, as well as the marginal carbonate platform of SW Poland. Filled fissures were recorded in the lower part of the Jabłonna Reef. The aragonite cementation recorded in some fissure fillings implies that they originated in rocks exposed on the sea floor and are neptunian dykes.
Źródło:: Annales Societatis Geologorum Poloniae; 2016, 86, 4; 379-413
0208-9068
Pojawia się w:: Annales Societatis Geologorum Poloniae
Dostawca treści:: Biblioteka Nauki

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