Dolines and Sinkholes: Aspects of Evolution and Problems of Classification

»Doline«, mednarodni izraz za vrtaco, je najbolj razsirjena povrsinska oblika na krasu. Ime izhaja iz slovanske besede »dolina«, ki pomeni depresijo v topografskem povrsju. V skoraj 100 letih se je izraz razsiril in danes ima v mednarodni literaturi dobro dolocen pomen. Zaradi tega ga ni mogoce zamenjati s kakim drugim izrazom, npr. »vrtaca« ali "kraska dolina" kot predlagajo nekateri avtorji (Gams 1973, 1974). Uporaba izraza »sinkhole« kot sinonima za »doline« v ameriski literaturi vodi vcasih do podvajanj, saj se izraz »sinkhole« uporablja predvsem za udorno ali pokrito vrtaco. Na podlagi podrobnega preucevanja vrtac na razlicnih kraskih ozemljih je mogoce trditi, da je vrtaca lahko tako po strukturi kot po nastanku, kompleksna oblika (Sauro in print, a in b). Vrtaco lahko najpravilneje opredelimo tako, da dodamo pridevnik, ki pojasnjuje posebnosti. Najpomembnejsi pridevniki so tisti, ki so vezani tako na morfogenetske mehanizme kot na hidroloske posebnosti. Na podlagi teh pridevnikov je mogoce razlikovati vec kategorij in tipov vrtac. Za razumevanje vrtace je najbolj pomembna rekonstrukcija njenega razvoja, pa cetudi je ta kompleksen. The doline is the most representative landform of the karst surface. The name derives from the word dolina, a Slav term indicating any depression in the topographical surface. For nearly a century, this name acquired widespread use and a well defined meaning in the international literature; as a result it is not possible to substitute it with another term such as “vrtaca” or “kraska dolina”, for example, as proposed by some authors (Gams, 1973, 1974). The use of sinkhole as a synonym for doline in the American literature has also created some ambiguity, because sinkhole is mostly applied in the sense of collapse doline or of cover doline. From the detailed studies of the dolines of different karst areas, it is possible to infer that the structure and the genesis of this form may be complex (Sauro, in press – a – and - b). The most correct way to define a doline is to add an adjective indicating a peculiar attribute. The most significant attributes are those linked to both the morphogenetical mechanism and the hydrological structure. On the basis of these attributes it is possible to distinguish several categories and types of dolines. Most importantly to understand a doline it is necessary to be able to reconstruct its history even if that may be complex, as some dolines formed by specific processes may later further evolve through different processes.