Original paper Architecture of thrust faults with alongstrike variations in fault-plane dip: anatomy of the Lusatian Fault, Bohemian Massif

The Lusatian Fault in the northern Bohemian Massif is one of the most prominent products of the latest Cretaceous to Paleogene thrusting in the Alpine foreland in Europe. Its fault plane dips to the N to NE, typically separating crystalline units in the N from Upper Paleozoic and Cretaceous units in the south. Crystalline units in Lusatia consist of Proterozoic to Lower Paleozoic rocks epi- to mesozonally metamorphosed during the Variscan Orogeny, cut by Cadomian and Variscan granitoid plutons. Anatomy of the fault was studied in outcrops and in a series of test trenches, and the course of fault trace in complex topography was used to determine the dip of the fault. Based on a detailed analysis of brittle structures accompanying the main fault, the Lusatian Fault Belt can be further subdivided into the fault core, zone of wall-rock brecciation, and the damage zone which also includes large-scale dismembered blocks and flanking structures. Other components of the fault belt originated in spatial association with the Lusatian Fault, during its formation (e.g., the drag zone and bedding-plane slips in the footwall-block sediments) or later, during its multi-stage evolution. A general dependence of fault belt architecture on the orientation of the fault plane to the acting stress can be demonstrated. With the NNE–SSW subhorizontal maximum principal stress calculated for the thrusting episode at the Lusatian Fault, less complex structures appear where the dip of the fault is shallower, and more complex structures including thicker damage zone and drag zone were formed where the fault was steeper. In flat fault segments, competent members of the footwall-block sedimentary package, whose bedding planes were sub-conformable to the fault plane, were sheare