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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 28 (1981), S. 0 
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Phacotus and Coccomonas, two carbonate-secreting, non-marine, planktonic chlorophyte genera, are important sediment contributors mainly in hard water lakes. The calcite loricae of these flagellate algae exhibit characteristic features easily recognizable under the microscope, making Phacotus and Coccomonas important facies fossils for the recognition of ancient non-marine environments.The fossil record of Phacotus can be traced back to the Miocene and it is probable that further research could extend this record into pre-Tertiary periods.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 18 (1972), S. 0 
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Semi-quantitative clay. mineral analysis was carried out on the clay and silt fractions of approximately three hundred Black Sea core samples. Relative abundance of montmorillonite, illite, kaolinite and chlorite was determined.Illite is the most frequent clay mineral in the Black Sea surface sediments. Highest values are obtained in the northern and central Black Sea. Approaching the Anatolian coast, the illite portion gradually decreases at the expense of montmorillonite. Chlorite and kaolinite occur generally only in small quantities. The lateral changes in the composition of the clay minerals can easily be traced back to the petrology of a northern (rich in illite) and a southern (rich in montmorillonite) distributive area.In almost all cores a periodical fluctuation of the montmorillonite/illite ratio with depth could be observed which may be related to the changing influence of the two distributive provinces during the Holocene and Late Pleistocene (Würm). Higher montmorillonite contents indicate arctic and subarctic climate periods in the northern distributive area during which the illite supply was diminished to a large extent.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 17 (1971), S. 0 
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Coccoliths are the main constituents of the carbonate layers in several Oligocene bituminous shales as well as in the Oligocene “Helle Mergelkalke” limestone, Upper Rhine Graben and Bavarian Molasse Trough.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 12 (1969), S. 0 
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: SUMMARYAlong the eastern coast of the Gez Gölö, a salt lake formerly belonging to the larger “Paleo-Tuz Gölö” in central Anatolia, about 6.5 m of lake sediments of probably Pleistocene age were studied.The sediment series consists of fine-grained unconsolidated dolomite muds representing the basin sedimentation of the old lake.Nine lithified beds (oomicrites, intramicrites, intraoomicrites, intrabiomi-crites and dololutites with smaller amounts of allochems) are intercalated. These beds were deposited in very shallow water in the littoral zone of the paleo-lake. There is direct evidence that the beds were occasionally exposed to the air after deposition. This led to desiccation (with mud cracks, breaking up of intraclasts) and subaerial cementation due to the influx of fresh water (rain water, springs).These now lithified carbonate sedimentary rocks were submerged and subsequently covered with mud. During this sub-aquatic phase the rock beds as well as the unconsolidated muds were dolomitized by an extremely high Mg/Caratio of the lake water which in the present Tuz Gölü amounts to about 150! It cannot be excluded, however, that dolomitization already took place or was initiated during the subaerial phase (“supratidal dolomite”).
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 28 (1981), S. 0 
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Sedimentation rates were determined with the 210Pb method in eight sediment cores from Lake Constance. The rate of deposition in the main basin (Obersee) varies from about 0.06 g cm−2 y−1 in the central part to 0.13 g cm−2 y−1 in the eastern part of the lake and then increases rapidly towards the Rhine delta.In the central lake area the rate of deposition has been approximately constant since 1900, and dating with the 210Pb method is in good agreement with sedimentological observations. In the Konstanzer Trichter area, the deposition rate has been increasing since about 1955 as a result of eutrophication and subsequent high carbonate production.Dating with 137Cs is fairly accurate for sediments deposited at a high rate, but is questionable for slowly accumulating ones.A positive correlation of 210Pb fluxes and sedimentation rates indicates that 210Pb flux into sediments follows the distribution pattern of solids. 210Pb profiles in four sediment cores interpreted in terms of a constant flux model display synchronous fluctuations of the sedimentation rate; however, their relation to long-range particulate input variations remains to be proved.Sedimentation rates determined with the 210Pb method were used to calculate recent nutrient and heavy metal fluxes. Anthropogenic fluxes of Zn and Pb are in the same range of magnitude as in other polluted areas in Europe and America.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 20 (1973), S. 0 
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: A strong correlation in the geometry and mineralogy of two cement generations of a Quaternary with a Precambrian calcarenite enables us to reconstruct the diagenetic history of the Precambrian limestone. Both calcarenites contain two cement generations (A and B) of which A consists of dolomite, B of calcite.The following diagenetic stages can be recognized: after deposition of the allochems in a shallow marine environment, cementation in the intertidal zone with magnesian calcite (cement A) led to the formation of beachrock (Stage 1).By lowering of the sea level, the beach rock was shifted into the supratidal zone, but still remained under the predominant influence of the sea water (breakers, spray). During longer periods of aridity, the magnesian calcite of cement A and of the allochems was transformed into dolomite by brines derived from sea water with very high Mg/Ca ratio (〉 15), whereas aragonite and calcite remained unaffected.After further lowering of the sea, an increasing influence of meteoric water caused the wet transformation of aragonitic allochems to sparry calcite and to the precipitation of sparry calcitic cement B.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 224 (1969), S. 258-259 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The sedimentation process in the Untersee is governed by the deposition of carbonate rich clayey silt muds resulting from suspended load of the Rhine River, by cal-cite produced in the littoral zone by blue-green algae and aquatic plants2'3 plus organic material derived from these plants and the ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 217 (1968), S. 836-837 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The lake has a surface of 540 km2 and a maximum depth of 252 m; its longest axis is 69 km and the maximum width about 15 km. There have been two principal theories of the origin of the lake and its basin: (a) the structural theory; and (b) the glacial theory. There is also (c), a combination of (a) ...
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Mineralogy and petrology 31 (1983), S. 193-206 
    ISSN: 1438-1168
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Summary The investigation of the heavy metal concentrations of a sedimentary core from the northern part of the Attersee (Austria) revealed a bipartition of the core: a lower part (below 20 cm depth within the sediment) with generally low metal concentrations and an upper (above 20 cm depth) section, in which Cd, Zn and Pb begin to rise until a 5.6-fold (Cd), 3.1-fold (Zn) and 1.9-fold (Pb) increase is attained in the uppermost 6-4 cm layers within the sediment.210Pb and137Cs dating designate 1870–1880 as the initial stage of heavy metal pollution originating from anthropogenic sources and 1960–65 as the stage of maximum enrichment. The highest metal concentrations are in the same range as concentrations described from sediments from 7 lakes in Upper Bavaria with a similar setting (recreational areas with little or no industry). Domestic sewage and rural runoff in connection with the immission of atmospheric dust enriched in heavy metals which result mainly from coal combustion are believed to be the major metal sources. The overall low P-concentrations in the lake sediments do not vary with depth; they indicate that present oligotrophic conditions of the lake have persisted for centuries.
    Notes: Zusammenfassung Die Untersuchung eines Sedimentkerns aus dem nördlichen Teil des Attersees (Österreich) zeigt, daß die Schwermetalle Cd, Zn und Pb ab einer Sedimenttiefe von 20 cm (Sediment-Alter 1870–1880) nach oben hin±kontineuierlich ansteigen und ihre Maximalkonzentration in einer Sedimenttiefe von 6-4 cm (1960–1965) erreichen. Im Vergleich zu den unterhalb von 20 cm abgelagerten Sedimenten (die Schwermetallgehalte entsprechen dem “präzivilisatorischen Background”) sind die Schwermetallkonzentrationen in den obersten 5 cm des Kerns 5,6fach (Cd), 3,1fach (Zn) und 1,9fach (Pb) höher als Folge des Schwermetalleintrags aus häuslichen und ländlichen Abwässern sowie aus dem Eintrag von stark schwermetall-belastetem Flugstaub, der vor allem aus der Verbrennung von Steinkohle stammt. Die in den obersten Lagen des Attersee-Kernes gemessenen Konzentrationen an Cd, Zn und Pb liegen ähnlich hoch wie in Oberflächen-Sedimenten mehrerer anderer Seen Oberbayerns in Gebieten, deren Struktur mit dem Atterseegebiet vergleichbar ist. Der (insgesamt niedrige) Phosphatgehalt der Sedimente zeigt keine Abhängigkeit von der Tiefe und bestätigt den auch heute noch andauernden oligotrophen Zustand des Gewässers.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 82 (1995), S. 135-136 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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