Naslov
Caves of shallow phreatic and epiphreatic zone in Sabljaci lake area(Ogulin region, Croatia)

Autori
Buzjak, Nenad ; Kovač Konrad, Petra ; Jalžić, Vedran

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
18th International Karstological School "Classical Karst". Abstracts / Mihevc, Andrej ; Prelovšek, Mitja ; Zupan Hajna, Nadja - Postojna : Karst Research Institute - ZRC SAZU, 2010, 27-27

Skup
18th International Karstological School "Classical Karst"

Mjesto i datum
Postojna, Slovenija, 14.06.2010. - 18.06.2010

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
spring cave; shallow phreatic zone; epiphreatic zone; speleomorphology

Sažetak
First speleological researches of Ogulin region in the hearth of Dinaric karst in Croatia started in 19th century, but systematic researches of numerous cave springs and caves have been performing since 2006 during cave diving and biospeleological projects organized by SO HPD Željezničar (Zagreb) and Croatian Biospeleological Society. These researches include the coast and nearby surroundings of Sabljaci accumulation lake near the city of Ogulin. The lake was built in 1959 on the river of Zagorska Mrežnica for Gojak power station. It collects water from few karst springs and short tributaries feeding from the aquifer which hydrogeological conditions were determined by geological and tectonic settings. The permanency and relatively constant amounts of karst water that springs from this well developed system shows that they feed from a larger area. It is the mountain area of Mala Kapela that is dominantly built of highly karstified Cretaceous limestone beds with average amount of precipitation of 2000-3000 mm/year. The connections were confirmed by water tracing and speleological researches of wider area. The depth and flow conditions in the research area of Sabljaci lake were influenced by the depth of hydrogeological barrier and tectonic zones that controls flow directions. At the southern and south-western Sabljaci lake shoreline momentary the longest is Zagorska Mrežnica spring cave (1170 m long and 22 m deep). In its close vicinity there is Bistrac spring cave (500 m long and 56 m deep). Zagorska peć is a periodical spring cave with submerged shaft passage where cave divers went 76 m deep and in very demanding technical dive did not reached the bottom yet. According to historic documents it has the largest water level oscillation among all researched springs. During 2009 cave dive expedition and later dives on the west coast of the lake, Pećine – Veliko vrelo cave system was explored. It consists of lower submerged system of passages and upper periodically submerged cave passage. Up to now more than 1300 m of passages were investigated of which 725 m was surveyed. South of the lake Rupećica – Zeleno jezero system was researched. It starts with 80 m long Rupećica cave spring. Its stream flows through a closed depression (collapsed cave) and sinks to 160 m long and 22 m deep Rupećica ponor connected to Zeleno jezero lake which is a submerged shaft. Speleogenesis of submerged passages of shallow phreatic and epiphreatic zone in researched spring caves in Zagorska Mrežnica basin were determined by the position of complete barriers (dolomites and clastites), partial barriers (limestones and dolomites) and karstified beds (limestones) of Jurassic age. Besides geomorphological and hydrological features of the caves typical for shallow phreatic and epiphreatic conditions, it was found that all of them are important habitats with rare, specific and endangered cave species, like Proteus Anguinus and unique cave freswater stygobitic sponge Eunapius subterraneus.

Izvorni jezik
Engleski

Znanstvena područja
Geografija

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