Information about the features of Kras, especially about the spring of Timavo river, Reka river and ©kocjanske caves (jame), was spread all over the world by the Greeks and the Romans (Strabo, Virgil, Plinius). From the 16th to the 19th century the periodic Lake of Cerknica was the most famous and the best described karst phenomenon (Valvasor, Steinberg). In the past two centuries several caves and other karst forms and curiosities were explored on the Kras, presenting today the properties of "Classical Karst" from where not only the name of karstology derives but the roots of speleology are found.
IMAGE: Rakov Skocjan - A Copper Engraving by Franc Anton Steinberg in "Gruendliche Nachricht von dem in dem Inner-Crein gelegenen Czirknitzer-See", 1758
Photo by Arne Hodalic
Schmidl (1854, 1858) contributed to the knowledge of the caves in Notranjsko (Inner Carniola) and introduced some Slovenian popular names for the most impressive karst features into the literature (jama, dolina, ponor). These names were adopted later in the international use.
The discovery of new parts of the Postojna Cave in 1818 marks a new period of speleological and karstological investigations in Slovenia. Thus the Postojnska jama is often called the cradle of speleobiology.
IMAGE:
Karst in Slovenia
Authors: Dr. Peter Habic and eng. Vili Kos.
The Encyclopedia of Slovenia, Vol. 5, Reference KRAS
The Alpine karst region is dissected by deep valleys, lying between ridges at an altitude from 1000 to 2800 m. The plateau-like segments below the highest peaks are small but quite extensive in Komna, Pokljuka, Jelovica, Mezakla etc. in the border part of the Alps. At high levels of the Alpine karst we can find all karst forms known in the Northern and Southern Limestone Alps (big dolines - kontas, small dolines with vertical walls - kotlic (sing.), all kind of karren). Recently the 11 km long alpine cave Poloska jama and some potholes with the depth between 700 and 1200 m (the Cernelsko brezno 1198 m, Skalarjevo brezno 911 m, Brezno pri Gamsovi glavici 817 m, Poloska jama 704 m) have been discovered.
In other Alpine karst areas the karstic hydrology is often the karst phenomenon. The underground waters can rise to the impervious ground but flow out to normal valleys. Karst waters come out as the sources in the Quaternary deposits at the bottoms of the valleys or directly from the steep rocky slopes in the form of waterfalls (the Savica, Boka, Soca). The Alpine karst waters are comparatively pure because the surface is barren, without thicker layers of soil, and less populated.
The Littoral Karst, extending along the Adriatic coast, is further divided into original Kras areas (called also Trieste Karst or Carso di Trieste) in the background of the Timavo spring, and, second, the karst of northern Istria.
The longest blind valley in Kras area is that of the Notranjsko Reka - Vremska dolina with its terraced bottom. The river Reka sinks into the caves Skocjanske jame. There are two fresh collapse dolines and many older collapse dolines there.
Cave research organizations of Slovenia have till now registered more than 700 caves and potholes in the area of ca. 500 km2 of the Classical Kras.
The Karst of Notranjsko (Inner Carniola) belongs to the central highest Dinaric belt. It is high, wooded and scarcely populated karst plateaus at an altitude of 800 to 1700 m with intermediate lower valley-like karst depressions at an altitude between 400 and 600 m are predominant in this area. The high out-flow karst can be subdivided in relation to structural tectonicand morphogenetic charateristics into more or less coherent hydrogeological units: the Banjsice, Trnovski gozd, Hrusica, Nanos, Javorniki, Sneznik, Krim, Velika gora, Kocevski Rog and the central part of the Gorjanci mountains. Karst waters flow out from these units to several directions and feed the karst springs in their border zones.
Lying between these high areas of out-flow karst is the central part of the through-flow karst of Notranjsko. Across it the surface and underground waters flow forming intermittently flowing streams that flood the karst poljes. A considerable part of the through-flow karst belongs to the drainage basin of the Ljubljanica river, but some waters drain also towards the Kolpa and Krka rivers.
There is the famous polje of Cerknica with its periodic lake, numerous springs on the southeastern part, and ponors in the central part and in the nortwestern side. In the year 1971 a sluice was built at the entrance of the ponor cave Karlovica which has prolonged the lake phase from 6 to 7 months yearly. The purpose of that is to intensify the fishing season on the lake, and tourism. The alternation of the dry and the flood phases, which was in early modern times a matter of admiration for so many scientists still persists.
In the Notranjsko podolje only the polje of Postojna - Pivka contains a bigger flysch area. The rivers draining the flysch have shaped many caves in Cretaceous limestone. The longest is Postojnska jama (19.5 km). On the 30 km2 the triangle territory among Postojna, Loz, and Logatec, there are 60 km of cave channels and this is the greatest cave density in Slovenia. The second valley-like depression includes the western part of Dolenjsko. Waters drain both to the Krka and to the Kolpa rivers. The polje of Kocevje (about 60 km2) is the greatest polje in Slovenia; it has also the character of a peripheral polje.
The karst of Dolenjsko belongs to the shallow out-flow through-flow karst of the inner Dinaric or Peripanonnian belt. The surface is covered with the thicker layer of the red karst soil, the typical terra rossa, which has made possible denser population in more continuous tracts of agricultural land-use. Gentler forms, dolines, uvala like depressions, even small karst poljes and rounded hills, are predominant in the karst relief. Waters derive from the impervious and dolomitic rims of the karst areas and flow only at small depth under the surface or even in shallow open canyons.
IMAGE: In 1818 Luka Cec a native of Postojna discovered the interior parts of the Postojna Cave. The photo shows the reconstruction of the then cave and the costumes of the visitors. His discovery wide opened the door to Postojna tourism.
Photo by Arne Hodalic
IMAGE: Massive natural bridge in Rakov Skocjan / a 2,5 km long sunken valley between Cerknica and Planina polje is a real Karst gem
Photo by Arne Hodalic
IMAGE: Planina polje - a world-famous example of a perfect polje in the karst
Photo by Bogdan Kladnik
IMAGE: Planina polje
Photo by Bogdan Kladnik
IMAGE: Planina jama
Photo by Bogdan Kladnik
IMAGE: Cerknica Lake
Photo by Bogdan Kladnik
IMAGE: Losko polje
Photo by Arne Hodalic
IMAGE: The watery Krizna jama
Photo by Arne Hodalic
IMAGE: Franci Bar: In boats at Calvaria in Kri¾na jama
IMAGE: Reka
Photo by Bogdan Klad
According to "Slovenia - Geographic Aspects of a New Independent European Nation", Ljubljana, 1992 By Peter Habic, Ph..D. Research Associate, The Institute of Karst Research, Centre of Scientific Research of the SAZU
IN THIS CHAPTER
©kocjanske jame | Postojnska jama
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