International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

CALCULATIONS OF TECTONIC, MAGMATIC AND RESIDUAL STRESS IN THE STIAVNICA STRATOVOLCANO, WESTERN CARPATHIANS: IMPLICATIONS FOR MINERAL PRECIPITATION PATHS

Pages: 19 - 36

Authors: MICHAL NEMCOK, PATRIK KONECNY, ONDREJ LEXA

Abstract: This paper describes the dynamics controlling the development of the Stiavnica stratovolcano and the distribution of related ore deposits during the Badenian–Pannonian (16.5–6.2 Ma) using combined structural, geobarometric and geothermometric analyses. During the early Badenian–earlier late Badenian (16.5–15 Ma) the Stiavnica area experienced NE-SW extension. It controlled NW-SE striking normal- and N-S trending sinistral strike-slip faults. Later, during the early Badenian–earlier late Badenian, the extension rotated to W-E and controlled N-S striking normal faults, NE-SW striking sinistral and NW-SE striking dextral strike-slip faults. Later, the extension rotated to NW-SE. The tectonic stress interacted with the rapid overbunden removal and magmatic stress of the granodiorite intrusion, during the late Badenian–early Sarmatian. The tectonic stress controlled NE-SW trending normal faults. Overbunden reduction input changed normal faulting to strike-slip faulting. Magmatic input caused the opening of subhorizontal veins above the intrusion and anastomosing fracture pattern around its boundary. Later during the late Badenian–early Sarmatian, the stress had a plane stress character (σ1 > σ2 > σ3), indicating neither collapse nor distinct regional extension. NE-SW striking normal faults, ENE-WSW striking sinistral and N-S striking dextral strike-slip faults were active. Normal faults and releasing bends of the strike-slip faults were places of ore deposit precipitation. During the Sarmatian–Pannonian (13.6–10.7 Ma), the stress progressively gained a strong oblate character (σ1 ≥ σ2 >>σ3), indicating strong regional NW-SE extension, controlling the same fault pattern. Later during the Pannonian, counterclockwise stress rotation towards N-S oriented σ1 and E-W oriented σ2 led to NE-SW oriented sinistral strike-slip faulting.

Keywords: Western Carpathians, Stiavnica stratovolcano, stress, temperature, fault, vein

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