Geomorphological properties of dolines in the northern part of Cres island

Ponikve su tipičniji krški reljefni oblici i važan su predmet istraživanja među geomorfolozima. Velika gustoća ponikava nalazi se na otoku Cresu, stoga je on izabran za analizu za analizu prostornog rasporeda i gustoće ponikava s obzirom na morfometrijske parametre reljefa i geološku građu. Za istraživanje je izabran sjeverni dio otoka koji je reljefno viši i šumovitiji od južnoga, a obuhvaća površinu od 149,15 km2. U analizi su korištene topografske karte 1:25 000 Vojno-geografskog instituta, Beograd. Digitalizacija i morfometrijske analize izrađene su pomoću ArcGIS 10.3.1 programskog paketa. Istraživanjem je utvrđeno da se najveća gustoća ponikava nalazi na području Tramuntane. Utvrđeno je i da se najveći udio ponikava nalazi na visinama 200 – 300 i 300 – 400 m, na nagibima padina 2 – 5° te u zonama vertikalne raščlanjenosti 30 – 100 i 100 – 300 m/km2, a također je ustanovljeno da se najveći udio ponikava nalazi na područjima izgrađenima od vapnenaca i dolomita (stratigrafska jedinica K1) te da osim litološke građe na prostorni raspored ponikava utječe i tektonika.Dolines are typical karst relief forms and are an important research subject among geomorphologists. The high density of dolines is observed on the island of Cres which has been chosen for the analysis of spatial distribution and density of dolines with respect to morphometric parameters of relief and geological structure. Northern part of the island was selected for research, which is higher and more forested than the southern part. It covers an area of 149,15 km2. Topographic maps 1:25 000 of the Military Geographical Institute, Belgrade, were used in the analysis. All computer digitalization and morphometric analyses were performed using the ArcGIS 10.3.1 software package. The research established that the highest density of dolines is in the area of Tramuntana. It was also determined that most dolines are located at altitudes of 200 - 300 and 300 - 400 m, on the slopes of 2 - 5 ° and in the zones where values of vertical relief dissection are 30 - 100 and 100 - 300 m / km2. It was also established that most dolines are found in areas built of limestone and dolomite (stratigraphic unit K1). In addition to the lithological structure, the spatial distribution of dolines is also influenced by tectonics