Early Bashkirian Rugosa (Anthozoa) from the Donets Basin, Ukraine. Part 2. On the genera Axisvacuus gen. nov. and Falsiamplexus Fedorowski, 1987
FEDOROWSKI J.
1Institute of Geology, Adam Mickiewicz University, Maków Polnych 16, Pl- 61-606 Poznan, Poland.
jerzy@amu.edu.pl
ABSTRACT: Five species belonging to two genera: Falsiamplexus Fedorowski, 1987 and Axisvacuus gen. nov. are described
in detail and their species content and relationships are discussed. Both genera are perhaps related to
Rotiphyllum and were probably derived from it, but relationship of Falsiamplexus to Bradyphyllum Grabau,
1928 cannot be excluded. The new genus Axisvacuus is represented by four species, of which three are new:
A. verus (type species), A. extendus and A. semicirculatus. Stratigraphic ranges of species described are compared
to the western European and Russian standards (Table 1). Some possible palaeogeographic implications
of the occurrence of Axisvacuus postumus (Smith, 1931) and Falsiamplexus reductus Fedorowski, 1987 are
briefly discussed.
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Stromatoporoid growth orientation as a tool in palaeotopography: a case study from the Kadzielnia Quarry, Holy Cross Mountains, central Poland
LUCZYNSKI P.
Warsaw University, Institute of Geology, Al. Zwirki i Wigury 93, PL-02-089 Warszawa, Poland.
Piotr.Luczynski@uw.edu.pl
ABSTRACT: Growth orientation of stromatoporoids has allowed reconstruction of the palaeotopographic position of a large
Frasnian organic buildup exposed in the Kadzielnia Quarry in the Holy Cross Mountains, central Poland. Two
main, mature stage, stromatoporoid growth modes have been discerned: erect and semi-buried. The growth orientations
of the stromatoporoids were studied in 17 sections that expose four different facies in the quarry. The
inclinations of the basal surfaces of specimens and direction of the growth axes were measured and compared
in terms of different growth modes, facies and positions in the organic buildup. The results support the earlier
opinions that the inclined contact between the Kadzielnia stromatoporoid-coral limestones and the detrital limestones
is depositional and represents an inclined depositional surface, and that the Kadzielnia buildup developed
in a calm water setting below the storm wave base on a slope or at its foot. General conclusions emerging from
the studies are: 1) stromatoporoid growth directions hold a key to reconstructing ancient topography; 2) erect
stromatoporoids that grew on inclined surfaces changed the growth axes to the vertical direction during their
growth; and 3) stromatoporoid growth directions and particularly the changing mode of growth of erect forms
support the view that Palaeozoic stromatoporoids acted photosensitively.
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The Steinplatte complex (Late Triassic, Northern Calcareous Alps, Austria) – subsidence-controlled development of a carbonate-platform-to-intrashelfbasin-transition
KAUFMANN B.
Österreichische Akademie der Wissenschaften, Kommission für die paläontologische und stratigraphische Erforschung Österreichs (KPSOE), c/o Institut für Erdwissenschaften, Karl-Franzens-Universität Graz, Heinrichstrasse 26, A-8010 Graz, Austria.
bernd.kaufmann@uni-graz.at
ABSTRACT: In Rhaetian (Late Triassic) times, the Hauptdolomit/Dachstein carbonate shelf situated at the passive continental
margin of the northwestern Tethys was characterized by an extensional tectonic regime. Rifting and spreading
movements fragmented this shelf into a loosely fitted mosaic of fault-bounded blocks characterized by a differential
subsidence pattern. This is expressed in significant thickness variations of platform carbonates and in the formation
of the intrashelf Kössen Basin. In this study, it can be demonstrated that tectonic subsidence triggered the
development of a carbonate platform margin and that the influence of eustatic sea-level changes was negligible.
The Steinplatte complex developed at the transition of the Kössen Basin to the Dachstein Carbonate Platform.
Small-scale isolated carbonate mounds situated on a smoothly inclined homoclinal ramp characterized the
initial phase and acted as nuclei of further carbonate buildup growth. However, only the ideal palaeogeographic
position far enough away from the carbonate-suppressive terrigenous influence of the Kössen Beds, combined
with vigorous carbonate production stimulated by rapid subsidence-caused sea-level rise, favoured continuous
mound growth. Once established, the carbonate buildup was characterized by rapid aggradational growth, developing
a palaeogeographic high with a steep slope and a depression with decreased sedimentation behind,
several kilometres distant from the Dachstein Carbonate Platform. Contemporaneously, isostatic adjustment
caused an accommodation minimum on the nearby margin of the Dachstein Carbonate Platform leading to its
westward progradation. Fading out of subsidence caused filling of the former depression in the back of the
buildup by prograding shallow-water Dachstein Limestones. Thus, a new platform margin was established in the
Steinplatte area, elevated almost 200 m above the adjacent Kössen Basin.
At the Triassic-Jurassic boundary, the Steinplatte complex was subjected to subaerial exposure by a sudden
tectonic uplift followed by a rapid isostatic drop. Emergence is indicated by levels of karstified limestones directly
underlying supposed exposure surfaces. Final drowning of the Steinplatte complex as well as of the whole
Dachstein Carbonate Platform is indicated by the cover of Early Jurassic (Sinemurian) deeper water, ammonitebearing
limestones (Adnet Formation).
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Reconstructions of the early and middle Holocene climate and environment based on δ13C and δ18O records in biogenic carbonates; Lake Niepruszewskie, western Poland
APOLINARSKA K.
Institute of Geology, Adam Mickiewicz University, Maków Polnych 16, PL-61-606 Poznan, Poland.
karinaap@amu.edu.pl
ABSTRACT: The present study investigates environmental conditions during sediment accumulation in Lake Niepruszewskie,
western Poland. Palaeolimnological reconstructions are based on stable isotope composition (δ13C and δ18O) of
a wide range of biogenic carbonates occurring in the sediments, including shells of several gastropod species
and the bivalve genus Pisidium, carapaces of ostracods belonging to the subfamily Candoninae and encrustations
and oogonia of the aquatic macrophyte genus Chara. According to the radiocarbon dates obtained, accumulation
of the sediment sequence began in the early Atlantic and terminated in the early Subboreal.
Both δ13C and δ18O records reveal significant and frequent fluctuations that are attributed to repeated changes
in the Lake Niepruszewskie water balance. However, conditions of prevailing long water residence time, accompanied
by high productivity within the lake, are reflected in a 13C-enriched carbon-isotope record.Minimum
δ13C and δ18O values were recorded for the earliest Atlantic and maximum values characterize the interglacial
optimum during the middle and late Atlantic.
Discrepancies observed between isotope records of particular taxa reflect the specific season and subhabitat
of each carbonate secretion. 13C-enriched Chara encrustations and oogonia are consistent with their precipitation
within the photic zone, which is commonly 13C-enriched due to the photosynthetic activity of macrophytes and
phytoplankton. The carbon isotope composition of Lymnaea auricularia shells indicates that breathing behaviour
leaves its imprint on δ13C in snail shells. In aquatic air-breathing pulmonate gastropods this results in 13C-depletion
in shells. Isotope records of individual shells of two snail species, Valvata piscinalis and Gyraulus laevis, indicate
that in order to obtain mean δ13C and δ18O values that are representative of a 5 cm thick sampling interval,
stable isotope signatures of more than five shells must be obtained.
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Geochemistry and age of groundwater in a hydrochemically diversified aquifer (Permo-Carboniferous, the Intra-Sudetic Synclinorium, SW Poland) derived from geochemical modelling and isotopic studies
DOBRZYNSKI D.
Institute of Hydrogeology and Engineering Geology, Faculty of Geology, University of Warsaw, Zwirki i Wigury 93, PL-02-089 Warsaw, Poland.
dardob@uw.edu.pl
ABSTRACT: Comprehensive investigations of groundwater were performed in a sedimentary aquifer of Permo-Carboniferous,
Intra-Sudetic Synclinorium, in SWPoland. The investigation included aqueous chemical and isotopic composition,
chemistry of mineral phases, geochemical modelling, and tritium and radiocarbon groundwater dating. Chemical
diversity in the groundwater system is created by the mixing of modern fresh water and older sulphate water with
higher dissolved solids. The system is treated as a system of flows of two end-member water types. Geochemical
modelling is used for: (1) explaining the origin of the chemistry of both water components, (2) quantifying the
groundwater mixing, (3) correcting the radiocarbon age of the groundwater for the effects of chemical water-rock
interactions, and (4) calculating reaction rates. Study of stable (C, S, O, H) and unstable (3H, 14C) isotopes allowed
the inverse mass balance geochemical models to be verified and specified, and the groundwater to be dated.
The chemistry of the modern, tritium-bearing, fresh water is a result of dissolution of limestones, dolomites
and gypsum. The mean tritium-age of this water, based on the lumped-parameter approach, varies between 10
and 200 years. The sulphate mineral water owes its chemistry to the process of dedolomitization driven by gypsum
dissolution. Its radiocarbon age is about 5.9 ka BP, i.e., during the Mid-Holocene Climatic Optimum. Rates
of chemical reactions responsible for the formation of sulphate type water are estimated to be: dissolution of gypsum
(2.85 µmol/L/year) and dolomite (0.21 µmol/L/year), calcite precipitation (0.20 µmol/L/year), organic matter
decomposition (0.08 µmol/L/year).
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