WARSTWY ŚWIĘTOMARSKIE DEWONU ŚRODKOWEGO W GÓRACH ŚWIĘTOKRZYSKICH W ŚWIETLE BADAŃ SEDYMENTOLOGICZNYCH

Abstract

THE MIDDLE DEVONIAN ŚWIĘTOMARZ BEDS OF THE HOLY CROSS MTS IN THE LIGHT OF SEDIMENTOLOGICAL STUDYAbstract. The middle Givetian section of the Łysogóry region of the Holy Cross Mts (HCM) is highlighted by the presence of siliciclastic sediments of the Świętomarz Beds that occur between carbonate and clayey sediments of the Skały Beds and biostromal limestones of the Pokrzywianka Beds or claystones of the Nieczulice Beds. The Świętomarz Beds comprise six fades: (1) medium- and thick-bedded sandstones. (2) calcareous sandstones and siltstones (3) sedimentary disturbed sandstones and siltstones. (4) slump sandstones, (5) siltstones and thin-bedded sandstones. (6) siltstones. The presence of gravitational flows in the form of slump sandstones and debris and mud flows, which are associated with medium- and thick bedded sandstones linked to channel zones, indicate submarine deposition on an inclined floor within a basinal slope environment. Deposition of the Świętomarz Beds occurred in an area of deeper shelf within the proximal and distal parts of prodelta that belonged to a medium-sized delta system. Indications of pulsating sedimentation of thin-bedded sandstones and the presence of plant remains in siltstones point up to transport of terrigenous material primarily by hyperpycnal flows generated by river floods. Terrigenous material of the Świętomarz Beds was derived to the Łysogóry basin from the southeast. Sedimentation of the Świętomarz Beds is closely linked to the increased tectonic subsidence of the Middle Devonian basin in the Łysogóry region of HCM. Coeval siliciclastic sediments, which have been identified in the area of south-eastern Poland and western Volhynia in the Ukraine, are presumably related to deposition within the same delta system.