Temat: palaeosols - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: New ichnotaxa of vertebrate burrows from the Salt Wash Member, Upper Jurassic Morrison Formation, south-eastern Utah (USA)
Autorzy:: Raisanen, D. C. W.
Hasiotis, S. T.
Powiązania:: https://bibliotekanauki.pl/articles/191391.pdf
Data publikacji:: 2018
Wydawca:: Polskie Towarzystwo Geologiczne
Tematy:: ichnofossils
continental
palaeosols
fossorial
trace fossils
domichnia
polychresichnia
Opis:: Large-diameter burrows in pedogenically modified floodplain deposits in the Salt Wash Member, Upper Jurassic Morrison Formation, southeast Utah, U.S.A., are interpreted to have been constructed by mammals. They are distinguished as Daimonelix martini isp. nov., which exhibits a helical shaft down to a horizontal tunnel with a mean depth of 71.4 cm from the inferred palaeosurface. The mean path length of the shaft is 99.4 cm; mean dip of the whorls is 39°. The mean tunnel length is 42.3 cm. Shafts and tunnels are oval or elliptical in cross section with the horizontal diameter slightly larger than the vertical (ratio of -1.26:1); the shaft averages 9.2 cm wide and 7.3 cm tall; the tunnel averages 10.7 cm wide and 10.7 cm tall. The tracemaker was likely a fossorial mammal that used the burrow as a den to shelter when not foraging above ground; the burrows are domichnia. The other from the same member is Fractisemita henrii igen. nov. et isp. nov., a network of interconnected shafts and tunnels; shaft and tunnel segments are straight, curved, or helical. The segments are at angles of 0-89°; mean length of a section is 30.7 cm. The cross sections of all elements are oval or elliptical; the mean width is 6.3 cm and the mean height is 4.9 cm (ratio of -1.29:1). The burrows are interpreted as the work of a social mammal and represent multiple tracemaker behaviours: protection, denning, foraging, and possibly food storage. The burrows are polychresichnia. Surficial morphologic features preserved on the burrow walls of both types are interpreted as scratches made by the tracemaker claws and/or teeth. The burrows reveal the actions of small vertebrates not recorded by body fossils showing potential partitioning of the environment and availability of resources for small vertebrates.
Źródło:: Annales Societatis Geologorum Poloniae; 2018, 88, 2; 181-202
0208-9068
Pojawia się w:: Annales Societatis Geologorum Poloniae
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Facies and sedimentary environment of the carbonate-dominated Carpathian Keuper from the Tatricum domain: results from the Dolina Smytnia valley (Tatra Mts, Southern Poland)
Autorzy:: Jaglarz, P.
Powiązania:: https://bibliotekanauki.pl/articles/191920.pdf
Data publikacji:: 2010
Wydawca:: Polskie Towarzystwo Geologiczne
Tematy:: tectonics
climate
dolostones
palaeosols
uppermost Ladinian-Norian
High-Tatric Unit
Western Carpathians
Opis:: The paper focuses on an interpretation of sedimentary and early diagenetic environment in the carbonate-dominated uppermost Ladinian-Norian succession from the Tatricum domain of the Tatra Mountains as well as its controlling factors. Limestones with cherts are the product of pedogenic processes, formed during long-term exposures of carbonate substrate. Chalcedony cherts were formed during relatively early diagenesis of pedogenic limestones. Dolostones and dolomitic mudstones were deposited in a kind of salt marshes. Pseudomorphs after sulfates and absence of benthic fauna indicate increased salinity and intensive evaporation. Additionally, low TOC concentration suggests a low productivity in the basin. On the contrary, stable isotope signals indicate that the sedimentary environment was strongly affected by meteoric water. Moreover, 18O and concentration of Sr suggest that dolostones were formed under the influence of both marine and meteoric waters. Dolomitic mudstones could be deposited in a salt-marsh environment fed by distal sheet floods. Components of palynological material and organic compounds in black dolomitic mudstones indicate the terrestrial origin of organic matter. Dolomitic regoliths were formed as the result of subaerial exposure and karstification of dolostones. Coarse-grained siliciclastics and variegated mudstone are interpreted, respectively, as a fluvial channel and flood plain facies of ephemeric fluvial environment. Sedimentary environment of the Keuper sediments was controlled by two main factors: synsedimentary tectonic movements and climate changes. In the latest Ladinian, the Middle Triassic carbonate platform was emerged, what resulted in the development of palaeosols. Block tectonic movements affected the Tatricum Basin in Keuper time. Horsts were emerged, whereas troughs were filled with fluvial or salt marsh sediments. Intensive tectonic movements are suggested by seismic-generated slumps and abrupt facies changes. More intensive chemical weathering and intensive contribution of pure siliciclastics suggest climate pluvialization in late Ladinian-early Carnian time. On the contrary, domination of physical weathering indicates the aridization of climate in late Carnian?-Norian time. The upper Carnian?-Norian succession was formed in hot and semi-arid climate conditions. Long-term climate changes was masked by short-term climate fluctuations. Geochemical indicators suggest that dolostones represent more humid periods, whereas dolomitic mudstones relatively dry periods.
Źródło:: Annales Societatis Geologorum Poloniae; 2010, 80, No 2; 147-161
0208-9068
Pojawia się w:: Annales Societatis Geologorum Poloniae
Dostawca treści:: Biblioteka Nauki

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