Neotectonic activity of the Pravno fault in the area of the ?iar Mts.

摘要

The paper presents neotectonic interpretation of the Pravno fault in the Horná Nitra Basin and the ?iar Mts. which is located in central Slovakia. The investigated area, belonging to the Tatra-Fatra Belt, has complicated structure and can be characterized by Neogene horst-and-graben faulting. The Pravno fault is the tectonic structure of the NW–SE direction and it is observable mainly in the southern edge of the ?iar Mts. The total length of the observed fault is 19.84 kilometers. The fault as significant morphostructural feature is pronounced between villages of Pravenec and Rázto?no. The Lelovce Formation (Pontian–Pliocene) are the youngest deposits, which have been clearly disrupted by the Pravno fault. To obtain reliable evidence of the neotectonic activity were used morphostructural parameters, longitudinal valley curves, slope, aspect, horizontal and vertical curvature of landforms, mountain-front sinuosity and measure faceted slopes of the mountain-front which clearly indicate that the SW edge of the ?iar Mts. represented by the Pravno fault is tectonically predisposed morphostructural discontinuity. The fault was active primarily in the Neogene period, especially during the Badenian and Sarmatian. The Pravno fault (south-eastern segment) have partly eroded faceted surfaces, and suggest that this segment of fault was not significantly activated during neotectonic period. Faceted surfaces are occasionally covered with debris slope sediments and rounded. In the course of the Pravno fault, Pliocene-Quaternary alluvial fans are rarely developed. The slope map refer to sensitive fault interface, but it is not such strong and distinct as in the case of the Malá Magura fault. Finally, the Pravno fault is most probably neotectonic structure of the Central Western Carpathians.