STREFA TEKTONICZNA KRAKÓW–LUBLINIEC NA ODCINKU KRAKOWSKIM W ŚWIETLE DANYCH UZYSKANYCH Z NOWYCH OTWORÓW BADAWCZYCH TROJANOWICE 2 I CIANOWICE 2

Abstract

THE KRAKOW SECTOR OF THE KRAKOW LUBLINIEC TECTONIC ZONE IN THE LIGHT OF DATA OBTAINED FROM NEW BOREHOLES OF TROJANOWICE 2 AND CIANOWICE 2 Abstract. The paper presents the results of two fully cored exploratory boreholes of Trojanowice 2 and Cianowice 2 that targeted a depth of 600 m. They were drilled north of Krakow in 2007, in the villages of Grebynice and Zielonki. The main objective of the boreholes was to test the concepts on the nature of the contact zone between the Upper Silesian Block and the Malopolska Block in the northern outskirts of Krakow, and to map the trend of the Krakow–Lubliniec fault zone in this area. The zone is a boundary between the above-mentioned regional tectonic units. The Trojanowice 2 borehole reached the Lower Devonian deposits and the underlying Lower Cambrian rocks (Borzeta Formation (Fm.)) whose range is limited to the south-eastern part of the Upper Silesian Block. The Cianowice 2 borehole drilled (under the Jurassic) Ediacaran flysch-like siliciclastics, lithologically and tectonically similar to the coeval rocks identified in the western and southern part of the Malopolska Block. Therefore, it has been assumed that the Krakow–Lubliniec fault zone, separating the Upper Silesian Block from the Malopolska Block, is located between these boreholes. Based on data from the Trojanowice 2 borehole and other wells drilled in this area, it has been proved that the Krzeszowice Graben, accentuated in the structure of the Cenozoic (Miocene) and Mesozoic succession in the Krakow region, is of Variscan age and the bounding faults were reactivated during the Alpine movements. The Cianowice 2 borehole has enabled the examination and stratigraphic documentation of the Ediacaran rocks and allowed assigning the same age to the lithologically similar deposits in the adjacent Jerzmanowice, Beb³o and DB-4 boreholes. Previously, these deposits were included in the Silurian Mrzyglod Formation (Fm.). The paper also discusses the results of other studies that have been carried out during documenting of the boreholes.