Record details

    Koncepce devonských ostrovních elevací a vývoj porozit v macošském souvrství
Statement of responsibility
    Jindřich Hladil
Other titles
    Philosophy of the Devonian insular elevations (DIE) and evolution of porozity of the Macocha Formation
    Hladil, Jindřich, 1953-
Source title - serial
    Geologické výzkumy na Moravě a ve Slezsku
    Roč. 6
    s. 80-84
    2 obr., 5 bibl.
    Anglické resumé
    Zkr. název ser.: Geol. Výzk. Mor. Slez. v Roce 1998.
Subject group
    fáze fluidní
    jihovýchodní svahy Českého masivu
    moravskoslezské prevariské paleozoikum
    past stratigrafická
    pole ropo-plynové
    sedimenty karbonátové
Geographical name
    Krásná (Frýdek-Místek)
Abstract (in english)
   A series of low islands separated the main part of the Early to Middle Devoanian carbonate platform from a very shallow part of saline nearshore (Carpathian subcrops, eastern Moravia). Several kilometers large islands of this type were tectonically buttressed by elevated blocks of crystalline basement and the thickness of their carbonate cover was never high. The Mesozoic-Tertiary secondary porosity (5-20 v.%) is limited to the limbs of these islands. However, young dissolution is strictly confined to high-contrast rock fabric, e.g. breccias, or multiple paleokarst, dolomitization and silicification structures. These structures are products of strong diagenetical changes on the peripheries of the Devonian islands and reflect variety of superimposed events from Givetian/Frasnian to early/middle Visean, mainly the Famennian and Tournaisian glacioeustatic lowstands.
   Temperature- and density-controlled circulation of pore fluids resulted in a pattern with many steep and fluctuating gradients and caused strong diagenetical changes of the carbonate rocks. Present definition of these Devonian insular elevations yields a new prospect for possible oil and gas traps. There is a paradox in the eastern Moravian subsurface, which contrasts with experience from many normal basins: Thin parts of the carbonate complex are very promising, whereas the continuous investigation of "stratigraphical reefs" does not have any importance for collectors or traps. These thick parts of the carbonate complex consists of well-bedded low-porosity rocks, where numerous organic-bearing micrite banks with dissolution-residue membranes considerably blocked any exchange of fluids and thus the observed porosity drop deep below 2%-level
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    31. 3. 2008
Import date
    8. 8. 2012