Record details

    Illite/smectite diagenesis in the autochthonous Miocene claystones of the Carpathian Foredeep
Statement of responsibility
    T. Dudek
Other titles
    15th Conference on Clay Mineralogy and Petrology, Brno, September 6-10, 1998 - Proceedings (Variant.)
    Dudek, T.
Source title - serial
    Scripta facultatis scientiarum naturalium Universitatis Masarykianae brunensis. Geology
    Vol. 28-29
    p. 55-66
    3 obr., 1 tab.
    Obsahuje bibliografické odkazy
    Zkr. název ser.: Scr. Univ. Masaryk. brun., Geol.
Subject group
    karpatská neogenní předhlubeň
    minerály smíšených struktur
Geographical name
    Buszkowicki (Polsko-jihozápad)
    Jodlówka (Polsko-jihozápad)
    Polsko - jihozápad
    Ryszkowa Wola (Polsko-jihozápad)
    Zalazie (Polsko-jihozápad)
Abstract (in english)
   The conversion of smectite to illite has been studied by X-ray diffraction techniques in the Miocene claystones of the Carpathian Foredeep. Samples were taken from the four boreholes (Jodlówka-4, Buszkowiczki-4, Zalazie-2 and Ryszkowa Wola-7) located in the eastern part of the Polish segment of Carpathian Foredeep. The autochthonous Miocene sediments in Jodlówka-4 are buried under the 1500m thick Carpathian overthrust. The other three boreholes are situated north of the front line of the Carpathian overthrust. In three boreholes (Jodlówka-4, Buszkowiczki-4 and Zalazie-2), diagenetic evolution of illite/smectite has been observed as a general trend of decreasing % smectite (%S) in mixed-layer minerals with depth (from 70%S to 30%S), starting from a certain level (onset of illitization). In Ryszkowa Wola-7 the onset of illitization has not been observed. In Jodlówka-4 and Zalazie-2, the transition from random (RO) to ordered (R1) structures has been observed.
   The trends of illitization were correlated with present-day temperatures calculated on the basis of gamma-ray logs. Assuming that present-day geothermal gradient is similar to thermal conditions at the time of maximal burial of sediments and comparing the known temperatures of the R0/R1 transition (110-120°C) with the values estimated for the two boreholes, the erosion in the investigated region was calculated: 400-700 m for Jodlówka-4 and 500-780 m for Zalazie-2. In Jodlówka-4, the gradient of diagenesis (%S/100 m below the onset of illitization) is lower than in Buszkowiczki-4 and Zalazie-2. These differences are interpreted as related to different temperature of Miocene sediments beneath the Carpathians as compared to the parts of the basin not affected by the overthrusted cover. The temperature differences, in turn, might be due to more rapid subsidence of the Foredeep sediments beneath the Carpathians caused by load of nappes, relative to the northern parts of the basin
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    6. 3. 2008
Import date
    8. 8. 2012