On the central part of the Velebit Mountain the traces of the Pleistocene glaciation have been found. The domination of the dissected relief, characterized by numerous elevations and depressions, in the conditions of low temperatures and richess of snow precipitation during the Pleistocene were a very good predisposition for glaciation development on the central part of the Velebit Mt.Key words: moraines, Pleistocene, glacial valleys, cirques, plateau glaciers, Velebit Mt. Croatia Geomorfološki tragovi glacijacije u mlađem pleistocenu na Srednjem VelebituNa području Srednjeg Velebita utvrđeni su tragovi pleistocenske oledbe. Dominantna mrežasta struktura reljefa karakterizirana nizom uzvišenja i udubljenja u uvjetima niskih temperatura i bogatstva snježnih padalina tijekom pleistocena bili su iznimno povoljna predispozicja za razvoj oledbe na istraživanom području.

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Cilj ovog rada jest utvrditi temeljne uvjete i procese oblikovanja i razvoja reljefa te njegove opće geomorfološke značajke na prostoru Slunjske zaravni kao primjera prostrane krške zaravni Dinarskoga krša. Kako je geomorfološko kartiranje jedna od najvažnijih metoda geomorfološkog istraživanja, cilj je bio obaviti detaljno geomorfološko kartiranje te izraditi digitalnu geomorfološku bazu podataka. Na temelju dobivenih podataka provedene su geomorfološka analiza i sinteza te je izrađena detaljna digitalna geomorfološka karta tog područja u izvornome mjerilu 1 : 50.000. Razlučeni su dominantni morfogenetski procesi oblikovanja reljefa (strukturnogeomorfološki i egzogeomorfološki) te su utvrđene osnovne etape geomorfološke evolucije reljefa.Ključne riječi: zaravan u kršu, geomorfološko kartiranje, morfometrija, Slunjska zaravan, Dinarski krš, Hrvatska Geomorphological Characteristics of the Slunj Karst PlateauThe research goal has been to determine the basic conditions and processes of the relief formation and development, and to define its general geomorphologic characteristics on the area of the Slunj karst plateau, as an example of spacious plateaus of the Dinaric karst. Since geomorphological mapping is one of the most important methods of geomorphological research, the aim of this work was detail mapping and production of a digital geomorphologic map of the area. As the basis of the given data, geomorphologic analyses and synthesis were worked out and a detailed geomorphologic map to the scale 1:50,000 was made. The dominant morphogenetic processes of the relief formation (structuralmorphologic and exogeomorphologic) were distinguished, and basic stages of the relief geomorphologic evolution were determined. Key-words: karst plateau, geomorphological mapping, morphometry, Slunj karst plateau, Dinaric karst, Croatia UVODZaravni u kršu specifični su reljefni oblik poligenetskog tipa vezan uz karbonatnu podlogu. Prostrane zaravni Dinarskoga krša privlačile su znanstvenike iz mnogih krajeva, pa su upravo ondje nastajale prve teorije o načinu i vremenu postanka zaravni u kršu. U 19. i prvoj polovini 20. stoljeća razvijeno je više teorija, koje se mogu podijeliti na: fluvijalno-erozijske i erozijsko-denudacijske teorije (Penck,

Although natural basis cannot be a decisive criterion in defining borders, historical and politico-geographic development of the researched area reveals that natural bounds have been considerably used in the boundary demarcation between the Republic of Croatia and Republic of Slovenia. This can be also concluded for the analyzed sectors which are tied with the Žumberak Mountain and the Kupa and Čabranka River valleys. Besides natural favours (the boundary line runs over the top ridges of the mountain massif of Žumberak/Gorjanci, as well as along the river flows), one must point out the fact that it is adapted to spatial organization of the borderland. Therefore, the boundary line is subsequent and co-operative here. Evolutionally, the border and borderland developed from terra nullius, frontier, and, finally, since the 16th century, have become a boundary line on the rivers Kupa and Čabranka, and since 1816, on Žumberak. Consequently, in spite of disputes in particular historical periods about the researched area's state and property appurtenance, the border has a centuries-old continuity. This can explain that nowadays the quoted sectors are least disputable in the boundary demarcation of the two sovereignties.

The Una River Valley has complex characteristics defined by the interchange of gorges, basins and valley extensions. The river has adapted itself to the primary geologic structure and to the activity of tectonic movements. The longitudinal profile of the river is the result of numerous rapids, cascades and waterfalls, the formation of which is connected with calcareous sinter accumulation. Morphogenetic analysis has shown that a series of very attractive and strange relief forms is being formed in the riverbed of the River Una such as calcareous sinter barriers, sinter riverbeds, calcareous sinter islands and caves.Key Words: Una River, calcareous sinter, riverbed, micro-landforms Geomorfološke karakteristike gornjeg dijela doline Une između Martin Broda i PritokeKompleksnost doline rijeke Une očituje se u izmjeni sutjeski, zavala i kotlina. Rijeka se prilagodila primarnoj geološkoj strukturi i tektonskoj aktivnosti. Uzdužni profil rijeke rezultat je brojnih brzaca, kaskada i vodopada, čije je oblikovanje povezano s taloženjem sedre. Mofrogenetska analiza je pokazala da se u koritu rijeke Une stvara niz vrlo atraktivnih i neobičnih oblika: sedrene barijere, sedrena riječna korita, sedreni otoci i spilje.