Geological influence on the formation of Samar natural bridge and collapse valley of Ravna River from the NE Kučaj Mountains (Carpatho-Balkanides, eastern Serbia)

The paper deals with the description of Samar natural bridge and collapse valley of Ravna River in eastern Serbia aiming to suggest an interpretation of their origin and development, in relationship with lithological and tectonic conditions, karst processes, and petrological analyses. In this study we present the geological setting, detailed morphology and hypothesis on the genesis of these karst landforms. The relationship between surface karst development and the geology is considerably acknowledged. The major contribution of the paper is to propose a framework for considering how recrystallization of limestone can affect the weathering potential of karst landforms and to introduce a term collapse valley. Finally, this study shows that the weathering potencial of the Samar natural bridge is decreased concerning the diagenetic changes these limestones underwent.

Ovrednotenje kraških geomorfoloških točk na območju gora Kučaj in Beljanica kot izhodišče za ustanovitev geoparka na kraški osnovi

Protection and promotion of geoheritage has been changing and improving in recent decades, in line with the growing research in this field. Some research papers specifically study geomorphological geoheritage and introduce a special term − geomorphosite. Karst geomorphosites present specific objects of geomorphological heritage. On Kučaj and Beljanica mountains there is the largest karst area in Serbia. The purpose of this paper is to select and evaluate the scientific value of karst geomorphosites of Kučaj and Beljanica. More than one hundred karst geomorphosites were analyzed. In order to achieve more adequate coverage and representation, they were grouped into 25 geomorphotypes in three major geomorphological components of the investigated area. The results of this analysis highlighted the most important natural potentials of this area for establishing a karst-based geopark. More than 20 geomorphotypes have a positive recommendation index, which provides a good basis for further geotourism analysis.Zaščita in promocija geodediščine se v zadnjih desetletjih spreminjata in izboljšujeta, skladno s čedalje večjim številom tovrstnih raziskav. Nekateri raziskovalni članki posebej proučujejo geomorfološko geodediščino in uvajajo poseben izraz, geomorfološko točko. Kraške geomorfološke točke predstavljajo specifične cilje geomorfološke dediščine. Na gorah Kučaj in Beljanica je največje kraško območje v Srbiji. Namen prispevka je izbrati in ovrednotiti znanstveno vrednost kraških geomorfoloških točk Kučaja in Beljanice. Analiziranih je bilo več kot sto kraških geomorfoloških točk. Da bi se dosegli ustreznejša pokritost in zastopanost, so bile te točke združene v 25 geomorfoloških tipov treh glavnih geomorfoloških komponent raziskovalnega območja. Izsledki te analize so izpostavili najpomembnejše naravne potenciale tega območja za vzpostavitev geoparka na kraški osnovi. Več kot 20 geomorfoloških tipov ima pozitiven indeks priporočil, kar je dobro izhodišče za nadaljnjo analizo geoturizma