Some Geological Observations in Slovačka jama Cave (-1268m) in Velebit Mountain, Croatia

Abstract

Tekom zadnjih treh speleoloških odprav je bila Slovaška jama raziskana do globine 1268 m. V njej je več rovov freatičnih oblik. Hipsometrično najvišji ostanki takih rovov so najbrž v zvezi s ponori iz časa, ko je nastajala uvala Veliki Lubenovac. Spodnji, recentni in subrecentni freatični horizonti v jamskem “dnu” so verjetno del kanalov podzemeljske reke Like, ki ponika na severovzhodni strani Velebita in teče skozenj v podmorske izvire v Jadranskem morju. Ostali rovi so predvsem brezna in meandri z vadoznimi oblikami. Analize izotopa 14C dokazujejo, da so najstarejše sige v obojih, v starih in v subrecentnih freatičnih rovih, medtem ko so mlajše sige v vadoznih meandrih

During three speleological expeditions the Slovačka jama cave has been explored to the depth of 1268m. In the cave there are several channels with phreatic forms. The highest relict phreatic channel is probably due to sinkholes formed on the karst uvala Veliki Lubenovac at the time of uvala formation. Lower, recent and subrecent, phreatic horizons at the cave bottom are probably a part of the underground route of the Lika river which sinks on the north-eastern side of Velebit mountain and flows through the mountain to the submarine springs in the Adriatic sea. Other channels are mostly shafts and channels with meandering vadose forms. 14C isotope analysis of speleothems shows that the oldest are situated in both ancient and subrecent phreatic channels, while younger ones are found in the vadose meandering channel.