Lineaments in the Gravity Image of the Border Zone between the Central and Outer Carpathians

Abstract

The research area covers the border zone between the Central and Outer Carpathians. The purpose of this research was the interpretation of this zone based on a gravitational survey. This survey was integrated with the results of surface mapping, a deep seismic survey, and deep drillings. Three major tectonic units are located in this area: the Outer (Flysch) Carpathians, the Pieniny Klippen Belt (PKB), and the Central Carpathians. All three units contain a significant amount of flysch sequences. The lowering of the Bouguer anomaly value from north to south reflects the dip of the crystalline European Plate; in turn, the renewed increase in value correlates very well with the emergence of the crystalline ALCAPA Plate. The range of variability of the Bouguer anomaly value largely masks smaller anomalies in amplitude originating from smaller geological structures. Only three anomalies with significant horizontal extent and greater amplitudes are visible: two are clearly correlated with the Orava-Nowy Targ Basin and the third anomaly is likely connected with the thicker pile of the Outer Carpathian flysch. To separate the boundaries of geological or tectonic structures (lineaments), a horizontal derivative (THDR) and an analytical signal (ASA) were used. Both methods allowed us to confirm existing geological and tectonic boundaries (lineaments) and to identify new ones.