Kinematic and paleostress evolution of the NW-SE trending 'dinaric' faults in the northwestern external Dinarides

摘要

The main regional structures in the Dinarides where accumulated lithospheric stress has been relaxed are NW-SE trending Dinaric faults. The research involves kinematic and dynamic analysis of fault-slip data on the territory of the NW External Dinarides, including Middle Triassic to Middle Miocene strata.udFour major Tertiary-Quaternary tectonic phases have been documented. Paleostress analysis of fault-slip data shows general stress orientations, which have been correlated by relevant mesoscopic scale deformations. Relative chronology of tectonic phases is based on field observations of structural relationships. Tectonic phases have been placed in wider geodynamic context.udThe oldest phase is characterized by NE-SW directed compression in compressional stress regime, which has been attributted to Paleogene thrusting of the External Dinarides. The second phase is characterized by NE-SW oriented tension in extensional stress regime, which can be attributed to an influence of Middle Miocene extension in the Pannonian basin. The third phase is marked by E-W compression with N-S oriented tension in strike-slip stress regime, which could reflect cessation of subduction processes in Carpathians. The fourth phase shows N-S oriented compression with E-W oriented tension in strike-slip stress regime, which coincides with recent stress state of the region. The Triassic and Jurassic stress regimes have been evaluated according to the orientation of observed extensional structures.udThe structural model of NW External Dinarides teritory has been suggested according to the obtained results, which could be an usefull basis for the assessment of earthquake hazard, geomechanic rock stability and hydrogeological aquifer characteristics of the area.