Shallow Seismic Refraction Tomography Images from the Pieniny Klippen Belt (Southern Poland)

Abstract

The Pieniny Klippen Belt (PKB) is located between the Central and the Outer (Flysch) Carpathians and forms a narrow zone with a complex structure, often described as a mélange. It is composed of numerous tectonic elements of different size including strike-slip-bounded tectonic blocks, thrust units, toe thrusts and olistostromes combined together and representing different lithologies. To aid the geological interpretation of the mélanges of the PKB in the Spiskie Pieniny Mountain Region (South Poland), seismic refraction tomography was conducted. Isolated limestone outcrops consist of Jurassic limestones that stand out in the landscape. They form the horizontal narrow belt. In this belt, limestone olistoliths are surrounded by a matrix consisting of sandstones, mudstones and marl sequences forming a sedimentary mélange. The seismic refraction tomography measurements conducted along three profiles across this belt showed significant horizontal and vertical seismic velocity variations, which revealed the complex geological structure of this area. The Złatne, Branisko and Hulina Units were distinguished within the PKB structure. The high-velocity objects detected within the Hulina Unit were found to correspond to limestone outcrops and form isolated blocks surrounded by flysch deposits representing a chaotic sedimentary complex.