Precambrian and Palaeozoic basement of the Carpathian Foredeep and the adjacent Outer Carpathians (SE Poland and western Ukraine)

Zbigniew Buła, Ryszard Habryn

Abstract


In south-eastern Poland and western Ukraine, the Outer Carpathian orogen and the Carpathian Foredeep developed in the foreland of the East-European Platform (Baltica). The area consists of a number of tectonic units included in the Trans-European Suture Zone (TESZ): the Łysogóry–Radom and Małopolska blocks in the territory of Poland, and the Rava Rus’ka Zone, Kokhanivka Zone and Leżajsk Massif in the Ukraine. The development of the TESZ began in the (?Middle) Late Neoproterozoic and was associated with rifting processes taking place along the western edge of the East-European Craton (Baltica) during the break-up of the Rodinia/ Pannotia supercontinent. The passive margin of Baltica evolved into the TESZ during collisional and/or strike-slip movements. In the TESZ (Małopolska Block and Leżajsk Massif), Ediacaran flysch-type siliciclastics were affected by weak metamorphism and folding during the Cadomian orogeny. The development of Cambrian deposits in the East-European Craton, Łysogóry–Radom Block, northeastern part of the Małopolska Block (Kielce Fold Belt) and in the Rava Rus’ka and Kokhanivka zones was associated with the post-rift thermal subsidence. Tectonic movements (so-called Sandomierz phase), which occurred probably due to an oblique collision of the Małopolska Block (included into the passive margin of Baltica) and the East-European Craton during late Middle Cambrian to Late Cambrian (possibly also Early Ordovician) times, resulted in the following: (1) development of stratigraphical (?erosional) gaps in the Middle and Upper Cambrian sections of the Lublin–Podlasie slope of the East-European Craton and the Kielce Fold Belt in the Małopolska Block; (2) intense tectonic subsidence of the Łysogóry–Radom Block during the deposition of Middle and Upper Cambrian sediments; (3) development of compressional folds in the Lower Cambrian to lower Middle Cambrian deposits of the Kielce Fold Belt on the Małopolska Block. Ordovician–Silurian series were deposited in a typical flexural foredeep basin, in which subsidence and deposition rates accelerated during Late Silurian (Ludlow–Pridoli) and Early Devonian (Lochkovian) times. It is postulated that the present position of the Małopolska Block relative to the Łysogóry–Radom Block and East-European Craton resulted from post-Silurian dextral movements between the Małopolska Block and the East-European Craton. Devonian–Carboniferous deposits occur only in the Małopolska Block located in the Variscan foreland. The Middle-Late Devonian and Early Carboniferous shallow-marine carbonate platforms developed under an extensional regime. The siliciclastic Upper Visean–Lower Namurian A Culm series were deposited in the flexural Variscan foreland basin. During the Late Namurian A, the Małopolska Block was uplifted in response to the build-up of compressional foreland stresses. During post-Carboniferous times, the Precambrian and Palaeozoic deposits were subject to erosion and restructuring during the Alpine orogeny.

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