Nucleation and amplification of doubly-plunging anticlines: the Butkov pericline case study (Manín Unit, Western Carpathians)

Abstract

The Manín Unit represents a transitional tectonic element between the Central Western Carpathians and the Pieniny Klippen Belt. The overall map-view structure of the Manín Unit is dominated by elliptical antiforms composed of comparatively competent Jurassic and Lower Cretaceous strata, surrounded by soft Upper Cretaceous shales, marls and sandstones. During layer-parallel shortening, the Manín sedimentary succession behaved as a multilayer reinforced by a variously thick rigid layer of massive Urgonian limestone. The multilayer deformed by flexural slip folding, but the fold wavelength was controlled by the rigid layer undergoing buckling. It is inferred that, besides the lateral thickness differences in the rigid layer, development of brachyfolds and particularly periclines such as the Butkov fold also resulted from the interference of two perpendicular macroscopic fold systems.

Keywords

• Western Carpathians
• Pieniny Klippen Belt
• Manín Unit
• noncylindrical macrofolds
• Butkov pericline
• structural analysis