Record details

Title
    Obsah izotopů 13C a 18O v devonských karbonátech Moravského krasu : Specifický sekvenční vzor
Statement of responsibility
    Jindřich Hladil, Jana Hladíková
Other titles
    Content of the 13C and 18O izotopes in Devonian carbonates of the Moravian Karst: a specific sequence pattern
Author
    Hladíková, Jana
    Hladil, Jindřich, 1953-
Language
    česky
Source title - serial
    Geologické výzkumy na Moravě a ve Slezsku
Vol./nr.
    Roč. 4
Pages
    s. 57-63
Year
    1997
Notes
    4 obr., 1 tab., 14 bibl.
    Anglické resumé
    Zkr. název ser.: Geol. Výzk. Mor. Slez. v Roce 1996.
Subject group
    cyklus sedimentační
    devon
    geochemie izotopická
    izotopy C
    izotopy O
    karbonátová platforma
    moravskoslezský devon a spodní karbon
    sedimenty karbonátové
    zóny biostratigrafické
Geographical name
    ČR-Morava
    Moravský kras
Keyword
    13C
    18O
    Devonských
    Izotopů
    Karbonátech
    Krasu
    Moravského
    Obsah
    Sekvenční
    Specifický
    Vzor
Abstract (in english)
   The C and O isotope content in carbonate were evaluated in a pilot section through the 20Myr carbonate sequence of the Moravian Karst. In terms of formal stratigraphy, the sequence belong mostly to the Macocha Fm. (Eifelian to Famennian), with a maximum of sediment aggradation on platform during the Givetian and Frasnian. Amphipora wackestone, algal lime-mudstone and floatstone prevail. The values 13C and 18O of the section fluctuate in convergent/divergent way, so that a typical "mushroom" shape of curves characterizes the individual parasequences as well as minor cycles. A positive shift in 13C values of the upper part of the each cycle coincides with the negative shift in 13O values. We explain this feature by generally increased but even rising activity of algae and bacterians (more 13C in carbonate).
   The consistently decreased content of 18C could be ascribed to water of meteoritic origin as well as warm water on the platform (35-45C?, to values of 18O - 5 promile PDB).The stronger depletion in 18C corresponds to repetitive diagenetical changes of the carbonate, as documented in lithology of the basal parts of the sequence (emergence and erosion of the banks between the paraseq. I and II). The most generalized trends in isotope values rise almost through the entire sequence, with a depression only in its uppermost part. The mean isotopic composition of the Moravian Karst, i.e. roughly 13C+2 promile PDBa a 18O-6 promile PDB, differs from the so-called "normal" values of 13C and 18O of the Devonian carbonates, as estimated globally, i.e. approx. 13C+1 promile PDB a 18O-2 promile PDB)
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    31. 3. 2008
Import date
    8. 8. 2012