Klonów Beds (uppermost Silurian-?lowermost Devonian) and the problem of Caledonian deformations in the Holy Cross Mts.

Abstract

This paper presents the results of sedimentological, petrographical, stratigraphical and tectonic studies of the Klonów Beds from the Silurian/Devonian boundary interval in the Holy Cross Mts. They have been found in boreholes Klonów 1 and Klonów 2. Alluvial fan, braid plain and braid delta deposits have been recognized and characterized. A facies model has been constructed for the Klonów Beds which interfinger with Miedziana Góra Conglomerates and Bostów Beds. The occurrence of two marine basins, separated by an uplifted area located in the present-day Pasmo Główne Range, has been evidenced. A detailed lithological description of the cored sedimentary and pyroclastic deposits is given. Mineral composition of greywackes and arenites were analysed allowing determination of the geotectonic character of source areas. The source area for the Klonów and Bostów Beds were different zones of a recycled orogen whereas for the Barcza Beds - mainly a continental block. Palynological studies indicate that the Klonów Beds were deposited during the Pridoli and may correspond to the earliest Gedinnian. The studied rocks have been considered exhibit fault-fold tectonics. Geological processes, which took place at the decline of the Caledonian epoch at the boundary of the Kielce and Łysogóry Regions in the Holy Cross Mts., are described. A problem of molasses representing the decline of the Lower Palaeozoic sedimentary-diastrophic cycle is also discussed. It has been evidenced that the Kielce and Łysogóry units had become integrated into the single Holy Cross orogen during the Late Silurian - before the Klonów Beds were deposited, probably during the Ardennian tectonic movements.