Podrobnosti záznamu

Název
    Paleoenvironmental changes of the semipermanent Kalná Lake (Lower Permian), Krkonoše Piedmont Basin, Czech Republic: sedimentary and geochemical record
Údaj o odpovědnosti
    Martin Blecha, Karel Martínek, Martin Mihaljevič
Autor
    Blecha, Martin
    Martínek, Karel
    Mihaljevič, Martin
Jazyk
    anglicky
Zdrojový dokument - seriál
    Acta Universitatis Carolinae. Geologica
Svazek/č.
    Vol. 43, no. 4
Strany
    p. 657-665
Rok
    1999
Poznámky
    10 obr., 1 tab., 2 s.bibl.
    Zkr. název ser.: Acta Univ. Carol., Geol.
Předmětová skupina
    paleoprostředí
    perm-spodní
    podkrkonošská pánev
Klíčové slovo
    Basin
    Changes
    Czech
    Geochemical
    Kalná
    Krkonoše
    Lake
    Lower
    Paleoenvironmental
    Permian
    Piedmont
    Record
    Republic
    Sedimentary
    Semipermanent
Abstrakt (anglicky)
   Within the non-marine red beds of the Upper Paleozoic Krkonoše Piedmont Basin a letarally persistent lacustrine unit of lowermost Permian (Sakmarian, Lower Autunian) age occurs. This unit, called the Kalná "Horizon", consists of grey to variegated mudstones, carbonates, siltstones and sandstones of a total thickness about 10-20 metres and is interpreted as deposited in lacustrine offshore, nearshore amd mudflat environments of the semipermanent Kalná Lake. Underlying and overlying successions, consisting predominantly of red mudstones, are interpreted as deposits of a temporary lake and a low-gradient alluvial plain. To determine the hydrology and hydrochemistry of the ancient Kalnáí Lake, boron and exchangeable cation contents of lacustrine mudstones were studied. The offshore mudstones show significantly lower values of boron and exchangeable magnesium and kalium content in comparison to semipermanent mudflat facies, temporary lake and alluvial plain mudstones.
   No substantial dependence of the distribution of boron and exchangeable cations on changes within source area, mineralogy of mudstones, or the content of organic matter was found, therefore the changes in B and echangeable Mg and K contents are interpreted as changes of the lacustrine paleosalinity. Within the semipermanent Kalná Lake deposits, lake level oscillations of several orders were recognised. Geochemical results show low salinity during lake highsland and higher salinity during lake lowstand. These oscillations are interpreted as a record of climatically driven changes of hydrological regime. However, the generally lower salinity during the semipermanent Kalná Lake sedimentation, contrasting to higher salinity of temporary lake conditions is ascribed rather to tectonically driven increase in accommodation space in the centre of the basin, than to climatically driven change of lake hydrochemistry
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
    U
Datum vložení
    23. 7. 2008
Datum importu
    8. 8. 2012