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Ice Caves in Serbia
CHAPTER
ICE CAVES IN SERBIA
*
27
Dragan Nešić*, Jelena Ćalić†
Institute for Nature Conservation of Serbia, Niš, Serbia Geographical Institute “Jovan Cvijić” of the Serbian Academy of Sciences and Arts, Belgrade, Serbia†
C HAPTER OUTLINE 27.1 Introduction ................................................................................................................................ 611 27.2 History of Research ..................................................................................................................... 613 27.3 Types of Ice Caves in Serbia ........................................................................................................ 614 27.3.1 Perennial Ice Caves ............................................................................................. 614 27.3.2 Occasionally Perennial Ice Caves .......................................................................... 620 27.3.3 Seasonal Ice Caves .............................................................................................. 621 27.4 Outline of Temperature Dynamics ................................................................................................. 621 27.5 Conclusions ................................................................................................................................ 623 References ........................................................................................................................................... 623
27.1 INTRODUCTION In this chapter, the term “ice caves” refers to both perennial and seasonal ice caves, following the classification of Ford and Williams (2007), as opposed to the stricter classification by Luetscher and Jeannin (2004), which would, taking into account only perennial ice caves, leave Serbia with only four established sites. Considering the fact that in five of the listed ice caves, the ice sometimes lasts the whole year while in some years melts completely, we had to conditionally introduce the term “occasionally perennial,” which in this case lies in-between perennial and seasonal. In the Serbian geomorphology literature, the caves with ice and/or snow are called ledenice (ice caves) and snežnice (snow caves); these words are from the language of the native people, but are accepted in national scientific terminology as well (Gavrilović, 1974). Ice caves at temperate latitudes are usually expected to be located in the zones of relatively cold periglacial alpine environments in high mountain areas above the tree line. However, there are few such areas in Serbia, and most of them do not have an underlying carbonate geology. On the other hand, there are examples where ice and snow tend to accumulate in caves below the tree line for longer than an usual winter season. Such accumulations of subterranean ice are considered to be azonal processes, which are not typical for the given elevation range (zone). Exceptions of this kind are located mainly in the mediumhigh mountains of the Carpatho-Balkan and Dinaric ranges (Fig. 27.1) in Serbia. Locations of the ice caves fall between 670 m a.s.l. and 1776 m a.s.l. Ice Caves. https://doi.org/10.1016/B978-0-12-811739-2.00027-9 © 2018 Elsevier Inc. All rights reserved.
611
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CHAPTER 27 ICE CAVES IN SERBIA
FIG. 27.1 Spatial distribution of ice caves in Serbia (base map generated from SRTM data).
In general, it can be assumed, based on theory and the majority of literature references, that the ice in the perennial ice caves in Serbia is mostly of relict and endogenic character (formed through congelation of cave waters). Some seasonal ice caves host recent and/or exogenic ice, as well as snow accumulations at the entrances. Long-term observations, despite being very irregular in time, have indicated that ice in the static ice caves in Serbia is mostly formed by freezing of percolation waters and very rarely by concentrated input. Gradual transformation of snow to ice is mostly lacking, except
27.2 HISTORY OF RESEARCH
613
in the case of a unique perennial ice cave in SW Serbia (Lednica, in the village of Krnjača on Ožalj Mountain). High amount of precipitation in the colder parts of the year, and the absolute number of frosty and snowy days, has a significant impact on the quantity of underground ice (Nešić, 2002b).
27.2 HISTORY OF RESEARCH The first observation of an ice cave in Serbia dates back to the first half of the 19th century. French/ Austrian geologist Ami Boué (1840, 1891), during his geological explorations of the “European Turkey,” visited several caves in Serbia. One of them was the Rtanjska Ledenica ice cave on Mt. Rtanj in Eastern Serbia, where he measured the air temperature at the bottom. Mačaj (1866) mentioned the Tupižnička Ledenica ice cave in his general “topographic” overview of the Knjaževac county. The end of the 19th century in Serbian ice cave research was marked with explorations done by the founder of Serbian speleology and karstology, Jovan Cvijić (Cvijić, 1893, 1895, 1896). He gave a rather high hierarchical place to ice caves, within his general classification of caves: (1) “proper” caves (river caves and dry caves), (2) rock shelters, and (3) ice caves.
FIG. 27.2 Jovan Cvijić's sketches of ice caves in Eastern Serbia: (1) Rtanjska Ledenica, on Rtanj Mt.; (2) Stojkova Ledenica, on Kučaj Mt.; and (3) Ledenica u Ždrebici, on Suva Planina Mt. After Cvijić, J., 1895. Pećine i podzemna hidrografija u istočnoj Srbiji (Caves and underground hydrography in Eastern Serbia). Glas Srpske kraljevske akademije nauka, 46, 1–101 (in Serbian).
Cvijić compiled the first list of ice caves in Serbia (there were 11 of them at that time), with smallscale maps (Fig. 27.2) and air temperature measurements. Apart from stressing the prerequisites for the existence of ice caves—specific morphology (cold air traps), drip waters or snow—he suggested three classifications of ice caves: static and dynamic (although he stated that there are no dynamic examples in Serbia), “permanent” (perennial), and “periodic” (seasonal). Morphologically, Cvijić differentiated three types of ice caves: (a) short ice caves resembling rock shelters (mostly of N exposure, thick outside vegetation, mildly inclined single passage), (b) ice caves of “aven” (shaft) type (term borrowed from French; entrance at the bottom of a doline, inclined passage called “stromor,” and an ending small chamber), and (c) ice caves with shaft entrance (straight vertical channel of uniform cross-section descending to a large chamber). Cvijić also mentioned the local inhabitants' perceptions of the ice caves, either as small but valuable water reserves for shepherds on the waterless high karst plateaus or as a
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CHAPTER 27 ICE CAVES IN SERBIA
potential means for selling ice during the summer, for festivals and fairs. This is how he mentions the visit of Ami Boué to the Rtanjska Ledenica ice cave: Ami Boué visited Rtanjska Ledenica 58 years ago and it is of great importance to present his observations. Accompanied by the Serbian prince Miloš, he visited this ice cave in August 1836 (Die europäische Turkei von A. Boué I Band. Wien 1889, p. 88 – Recueil d'itinéraires dans la Turquie d'Europe par A. Boué, Tome second. Vienne 1854, p. 322). He found a lot of snow and ice in it, and measured the temperature of −2°C in the cave, while the air temperature outside of the cave was 23–24°C. At that time, there were thick woods around the Rtanjska Ledenica, while now it is surrounded mostly by meadows. (Cvijić, 1895)
In the second half of the 20th century, several geomorphologists (Petrović, 1964; Milić, 1968; Petrović, 1976; Lazarević, 1998) studied ice caves to a certain extent, but mostly within the broader analyses of general karst morphology. The beginning of the 21st century brought several new papers on ice caves, based on a series of temperature/humidity measurements, carried out mostly within seasonal dynamics during several years (Nešić, 2002a,b,c, 2017; Nešić et al. 2008a,b). There have been no data logging and no absolute dating of ice so far. Published papers on snow and ice in the underground karst of Serbia have focused mostly on particular scattered examples, but both detailed analytical research and summarizing, synthesis studies are generally lacking.
27.3 TYPES OF ICE CAVES IN SERBIA Based on the length of the extended duration of ice and snow in Serbian caves, the results of explorations and research and the previously mentioned classification criteria, we have identified 27 ice caves in Serbia. Four of them are perennial, five are occasionally perennial, and 18 are seasonal (Tables 27.1 and 27.2). At the time of Cvijić (1895), as many as 9 out of 11 known ice caves were perennial. He wrote, “In the remaining nine caves, the ice is present in July and even later, during the whole summer; they are therefore in the group of permanent ice caves.”
27.3.1 PERENNIAL ICE CAVES Perennial ice and snow occur in only four caves in Serbia, highlighting the rarity and irregularity of underground ice in azonal conditions below the tree line in the medium-high mountains. Three caves of this kind are situated in the Carpatho-Balkan mountains of Eastern Serbia, and one in the Internal Dinarides in southwestern Serbia. In the Carpatho-Balkanides, these caves are Tisova Jama on Beljanica Mountain (1336 m), Mijajlova Jama on Kučaj Mountain, and Provalija on Suva Planina Mountain (1808 m), while the Dinarides host Lednica ice cave, near the village of Krnjača on Ožalj Mountain, close to the border with Montenegro. Tisova Jama is situated in the central part of the high karstified plateau of Beljanica Mountain, with the entrance at 920 m a.s.l. The large cavity consists of a large doline, vertical passage, and a vast inclined chamber, 181 m long and 105 m wide (Fig. 27.3).
Table 27.1 Ice Caves in the Carpatho-Balkan Mountains of Eastern Serbia Entrance Elevation
Length
Depth
180-160
331
10-7
710
15-8
Kučaj Mt.
905
100-30
Zla Ledenica
Kučaj Mt.
900
30-15
150
37
6
Stojkova Ledenica
Kučaj Mt.
865
30-17
150
47
7
Rtanjska Ledenica Ledena Peć
Rtanj Mt.
926
24-9
63
40
Inclined
Beljanica Mt. Kučaj Mt.
670
9-6
108
18
Inclined
850
13-3
105
20
Inclined
Name
Location
1
Tisova Jama
Beljanica Mt.
920
2
Provalija
1649
3 4
Mijajlova Jama Dubašnica
Suva Planina Mt. Kučaj Mt.
5
8 9 10
11
12
Dobra Ledenica Ledenica u Maloj Brezovici Ledenica u Velikoj Brezovici Ledena Pećina
Kučaj Mt.
8
Passage Inclination
Origin of Ice
Duration of Ice/Snow
235
Vertical/ inclined
Snow
Perennial
58
58
Vertical
Snow
Perennial
297
167
Vertical/ inclined Vertical
Percolation water Percolation water Snow
Perennial
276
43
Vertical/ inclined Vertical/ inclined
Inclined
Snow and percolation water Percolation water Percolation water Percolation water Percolation water
Occasionally perennial Occasionally perennial Occasionally perennial Occasionally perennial Seasonal Seasonal Seasonal
Kučaj Mt.
Kučaj Mt. (Vrtačelje)
Source Ćalić Ljubojević and Ljubojević, 2000 Nešić, 2017
Petrović, 1976 cave register Petrović, 1964 Cvijić, 1895
Nešić, 2002a Cvijić, 1895 Petrović, 1964 Cvijić, 1893
Cvijić, 1893
922
5-4
231
92
Inclined/ cascading
Percolation water
Seasonal
Nešić et al., 2008a
615
Continued
27.3 TYPES OF ICE CAVES IN SERBIA
Entrance Dimensions
No
616
Table 27.1 Ice Caves in the Carpatho-Balkan Mountains of Eastern Serbia—cont'd Entrance Dimensions
Name
Location
13
Gaura Đin Šotaća
Kučaj Mt.
800
14
Tupižnica Mt. Devica Mt.
1060
13-11
63
26
1123
22-8
51
25
Devica Mt.
1145
8-4
42
18
Tupižnička Ledenica Veliki Ledenik Mali Ledenik Ledenik kod Sićermanske Livade Ledenik
19
Snežnica
20
Ledenica u Ždrebici
Svrljiške Planine Mt. Suva Planina
21
Krstasta Provalija Ledenica Trem
Suva Planina Suva Planina
15 16 17
22
Length
Depth
10
8.5
Passage Inclination
Origin of Ice
Duration of Ice/Snow
Inclined
Snow and percolation water Percolation water Percolation water Percolation water
Seasonal
Previnac, 1951
Seasonal
Nešić, 2002a
Seasonal
Nešić, 2002a
Seasonal
Nešić, 2001
Inclined/ vertical Inclined Inclined
Devica Mt.
Ozren Mt.
Source
Nešić, 2001
1120
43
20
Inclined
Percolation water
Seasonal
Cvijić, 1924 Cvijić, 1895
1370
18
24
Inclined
Snow and percolation water
Seasonal
Cvijić, 1895
Milić, 1962 1776
10-6
13
2
All dimensions are in meters (m). The numbers in the first column correspond to locations in Fig. 27.1.
Rock shelter
Snow and percolation water
Seasonal
Cvijić, 1895
CHAPTER 27 ICE CAVES IN SERBIA
Entrance Elevation
No
Table 27.2 Ice Caves in the Dinarides of Southwestern Serbia Entrance Dimensions
Krnjača village
1152
8-5
Piskova Poljana (Pešter) Vojselov Bunar (Pešter) Mezgraja (Pešter)
1518
7-3
69
6
Ponor cave
1215
2-10
43
23
Vertical/ inclined
1316
9
40
Vertical/ inclined
1346
1-14
11
Vertical structural cavity
Name
Location
23
Lednica
24
Ledenica
25
Špela Bores
26
Bezdan u Mezgraji
27
Golubova Pećina
Kamena Gora village
Length
37
Depth
All dimensions are in meters (m). The numbers in the first column correspond to locations in Fig. 27.1.
Passage Inclination
Origin of Ice
Duration of Ice/Snow
Vertical/ inclined
Snow and percolation water Percolation and inflow waters Percolation water and snow Percolation water and snow Snow and percolation water
Perennial
Personal observation
Occasionally perennial
Nešić, 2015
Seasonal
Nešić, 2015
Seasonal
Nešić, 2015
Seasonal
Personal observation
Source
27.3 TYPES OF ICE CAVES IN SERBIA
Entrance Elevation
No
617
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CHAPTER 27 ICE CAVES IN SERBIA
Tisova jama Beljanica, Serbia
0m
A –228 –210
–165
–235 m –203
–165 m
Plan –185 0
50
A
100 m
surveyed by Student Speleologic and Alpinistic Club (ASAK), Belgrade
340° – 160° A –215
N
A –215 m Projected elevations 0
50
100 m
70° – 250°
–235
FIG. 27.3 Cave map of the Tisova Jama. After Ćalić Ljubojević, J., Ljubojević, V., 1999. Tisova jama (Tisova Jama Cave). Zaštita prirode (Protection of Nature), 51 (2), 27–31 (in Serbian); Ćalić Ljubojević, J., Ljubojević, V., 2000. Caves below collapse dolines—case study of Tisova Jama (Eastern Serbia). Acta Carsol. 29 (2), 95–101.
The dimensions of the doline are 160 m by 180 m, with an approximate surface of 9.07 hectares. The total depth, measured from the rim of the doline, is 235 m. At -130 m, where the vertical passage enters the chamber, a large ice-snow accumulation, 50 m long and 10 m thick on average, with approximately 5000 m3 of accumulated ice and snow (Ćalić Ljubojević and Ljubojević, 1999, 2000) is present. The vast doline is the area that collects the snow in winter, from which the snow then slides farther down, like through a funnel. At the bottom of the vertical shaft, morphological conditions are favorable for ice and snow accumulation. It is suspected that the ice from the Tisova Jama dates back to the Little Ice Age (a period of colder climate), but this assumption needs to be checked by absolute dating methods. The difference between the ice quantity in 1988 and 1999, when this cave was twice surveyed, shows a decreasing trend (Ćalić Ljubojević and Ljubojević, 1999, 2000), which can probably be explained by the recent influence of climate changes (as also discussed by Luetscher et al. (2005), who used examples from the Swiss Jura to show the decay of cave ice in the past decades). Mijajlova Jama in the western part of the Kučaj mountains (710 m a.s.l.) is an impressive vertical cave with three entrances and a total depth of 167 m (Petrović, 1976). Through the freezing of percolation waters, ice crusts form on the walls of the shaft, further collapsing at the foot of the vertical drop to form accumulations of crushed ice and debris resembling an underground rock glacier. Suva Planina Mountain (1808 m) is the highest limestone morphostructure within the CarpathoBalkanides of Eastern Serbia and has a vast karst-leveled surface called Valožje (1400–1600 m). This area hosts both relict and recent high-mountain karst, as well as relict periglacial relief. Taking this into account, it is not strange that Provalija Cave (Fig. 27.4), located close to the mountain top (Trem, 1808 m), hosts perennial ice and snow accumulation (Nešić, 2017).
FIG. 27.4 Provalija Ice Cave (1 – Entrance; 2 – Step, pit; 3 – Firn; 4 – Ice; 5 – Terrace with rubble; 6 – Massive limestone). After Nešić, D., 2017. Jama Provalija na Suvoj planini (istočna Srbija), primer podzemnog visokoplaninskog karsta (Provalija pit on Suva planina (eastern Serbia), an example of underground high mountain karst). In: Proceedings of the 8th Symposium on Karst Protection, Pirot (in press).
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This cave is situated in the structural depression Kozija Grbina, SW of the highest peak, at 1649 m a.s.l. It consists of a sub-vertical passage 7–10 m in diameter and 58 m deep, but speleomorphological exploration is not complete yet. At the depth of 30 m, a large accumulation of compact ice is present, with a visible ice thickness of 8–10 m (volume about 385 m3). This is permanent ice with snow cover that fluctuates in thickness with seasonal weather conditions. On Suva Planina Mountain (Valožje plateau), other caves have been detected (e.g., Krstasta Provalija, Savina Propast; Milić, 1962) with indications of prolonged presence of ice and snow, but these phenomena are still insufficiently explored. There is only one known perennial ice cave in the Serbian part of the Dinarides: Lednica Cave in the village of Krnjača on Ožalj Mountain, located on the side of Tmuša sinking river, with entrances at 1152 m a.s.l. This cave is still insufficiently explored and has not been surveyed, but the first indications point out that one of the main factors of ice formation is the accumulation of snow. Below the entrances, the cave passage is inclined and covered with compact ice on a length of about 50 m. It seems that in the conditions of seasonal partial melt, the meltwater freezes again at the contact with the ice below. At the bottom of the cave a spacious chamber is present, which is the zone of cool air concentration. The climate of Lednica can be linked to its climatic context, with precipitation amounts in this part of the Dinarides exceeding 1000 mm (Ducić and Radovanović, 2005).
27.3.2 OCCASIONALLY PERENNIAL ICE CAVES Long-term observations, although at irregular intervals, especially during the last decade of the 20th century and since, have shown that there are several caves where ice lasts the whole year or longer, sometimes interrupted by periods without summer ice. For these ice caves, we have conditionally accepted the term “occasionally perennial ice caves.” Representatives of this group are Zla Ledenica, Stojkova Ledenica, and Dubašnica on Kučaj Mountain, Rtanjska (Mužinačka) Ledenica on Rtanj Mountain (Carpatho-Balkanides), as well as the Ledenica ice cave on the Pešter plateau in the Dinarides of southwestern Serbia. The data on Zla Ledenica (alternative name in Vlach language: Gaura Rea) are very scarce— just one source. Petrović (1964) published a short note about it, together with the nearby seasonal ice cave Dobra Ledenica (Gaura Bună). At the time of Petrović's explorations, in September 1962, there was an accumulation of ice and snow that probably, at least that year, lasted all year. However, personal contacts with the local population and hunters who visit the area, indicate that in recent years there has been no ice in Zla Ledenica, which must be taken conditionally because it was not verified. Stojkova Ledenica on the karst-leveled surface of Dubašnica in the eastern part of Kučaj Mountain was first explored and mapped by Cvijić (1895), then subsequently was visited by Jeannel and Racovitza (1929) within a biospeleological study, and in the second half of 20th century was remapped by Lazarević (1998). This is a large karst cavern whose entrance was formed by collapse. At the times of Cvijić and Lazarević, the cave was reported as having perennial ice, but in recent visits no ice was present in early autumn (Nešić, 2006, pers. comm.) Dubašnica Cave, also situated on eastern Kučaj, is the second deepest cave in Serbia (−276 m). Being almost completely a vertical pit, it is occasionally visited by caving teams for sports reasons, but unfortunately measurements of temperatures were never properly organized or published. The teams reported finding ice in summer months, but there were also years without deposited ice or snow.
27.4 OUTLINE OF TEMPERATURE DYNAMICS
621
The entrance to Rtanjska Ledenica on Rtanj Mountain, lies at an elevation of 926 m a.s.l. It is an example of a static ice cave with an inclined, 63-meter-long passage that reaches a maximum depth of 40 m. Freezing of percolation waters contribute greatly to the ice balance. In some years, the ice deposits exist during the summer and are continuous throughout the year or for several consecutive years. One such case was recorded in autumn 2004, when there was about 1 m3 of ice. Relatively detailed air temperature measurements (not data logging) were carried out in 1997 (Nešić, 2002a). Ami Boué visited this cave in 1836 and later wrote, “In Cretaceous limestones, natural shafts are also frequent, although they are rarely so nicely characterized as in the case of Ledenica, in the woods on the southern slopes of Mt. Rtanj” (Boué, 1891). Observations of the Ledenica Cave, located in the Žilindar-Kruščica area on the Pešter plateau in SW Serbia, fit well with what was written about occasionally perennial ice caves. Here, ice is formed by freezing of percolation and surface inflow water, as this cave is fed by a short ponor stream. On April 26, 2008, the whole surface of the cave was covered by an ice sheet 0.5–1 m thick, with a total volume of 40–50 m3, which by October 16, 2008, was reduced to 4.3 m3 (Nešić, 2015). This observation places the cave in the category of occasionally perennial ice cave, considering also the fact that during the explorations in the autumn of 2007, there was no ice at all.
27.3.3 SEASONAL ICE CAVES All other caves with ice and snow in the Serbian karst (Tables 27.1 and 27.2) are seasonal static ice caves, with annual renewal of ice and/or snow deposits, these lasting longer than snow outside the caves. The ice is primarily formed by freezing of percolation waters, and occasionally by snow firnification. In the seasonal static ice caves of Serbia, ice melts under the influence of heat advected by warm drip waters—reverse process than during formation of ice deposits—as well as the general warming of air, bedrock, and infills. The maximum recorded warming compared with the winter temperatures in these ice caves was 5.5°C (Nešić, 2002a). It can be concluded that seasonal ice caves are the dominant type of ice caves in the Serbian karst. On average, snow and ice in these caves lasts about 6–8 months per year, depending on weather conditions.
27.4 OUTLINE OF TEMPERATURE DYNAMICS There have been relatively few attempts to explain the climatic functioning of azonal static ice caves in Serbia (Cvijić, 1895; Nešić, 2002a). Measurements of cave climate parameters were carried out in Rtanjska Ledenica, Tupižnička Ledenica, and Veliki Ledenik caves on Devica Mountain. These measurements were done using the simple mercury thermometer (0.2°C precision), mounted on a tripod 1 m above the ground. Data loggers were not available. The results pointed to the regularity of permanent minimal negative air temperatures inside the ice caves (–0.2°C to –0.8°C) while outside temperatures were up to 6°C to 7°C, or very cold air from 0.4°C to 1.2°C, with outside temperatures of 14.8°C to 21.3°C (Nešić, 2002a; Nešić et al., 2008b). This climatic condition of permanent concentration of cold air in ice caves is called the “closed period” (e.g., Girardot and Trouillet, 1885, cited by Luetscher and Jeannin, 2004; Cvijić, 1895), which in present climatic conditions in Serbia occurs throughout most of the year (Fig. 27.5A and B). Inversion of air temperatures in the static ice caves was recorded during periods with outside negative air temperatures, while inside the ice caves
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(although with temperatures below zero), the temperature was several degrees warmer. This was recorded in Tupižnička Ledenica on January 9, 1997, when the temperature was −2.9°C outside the cave and −1.5°C inside the cave.
FIG. 27.5 Climatic functioning of the static ice cave Veliki Ledenik on Devica Mt.: (A, B) long-lasting static functioning (“closed period”) without noticeable air circulation; (C) extremely short-lasting dynamic moment, with observed and measured sudden inflow of cold air from the outside (“open period”); and (D) static phase, without noticeable air circulation, but with expected subsequent air inflow because of the difference in temperature (the moment was not observed in the field on a given date, but suspected).
More detailed observations were made in the Veliki Ledenik ice cave on Devica Mountain. On December 31, 1999, it was −6.2°C outside and −4.4°C inside, and on January 1, 2000, it was −8.8°C outside and −6.3°C inside (Nešić, 2002a) (Fig. 27.5D). This means that azonal ice caves may have a closed period even during temperature inversions. On the other hand, the same cave showed the dynamic characteristics typical for the open period on January 25, 1997. D. Nešić was carrying out temperature measurements in the cave during the temperature inversion, and exactly as he was taking the measurement, a sudden inflow of cold air caused a wind-like effect, with a temperature drop of 1.6°C (Fig. 27.5C). Based on a number of observations of climate conditions in ice caves and making top/bottom air temperature profiles, we came to the conclusion that the short open period of static ice caves, which refers to the inflow of cold air during the winter, should be linked only to the rare conditions of a sudden drop in the outside temperature on winter nights, whereas in general the main climatic characteristics of this type of ice cave remain unchanged (Nešić, 2002a).
REFERENCES
623
27.5 CONCLUSIONS Azonal static ice caves in Serbia are caves with permanent presence of cold air, which is, apart from the general climatic and weather conditions in the mountains below the tree line, mostly conditioned by the geometry of the caves. The most usual types are shallow inclined caves where the underground chambers are positioned laterally in relation to the mostly spacious entrances. This arrangement enables the formation of cold air traps, additionally helped by northerly exposed entrances, as well as by thick vegetation in their immediate surroundings, protecting them from direct sunlight. Ice caves in Serbia are distributed in an elevation belt between 670 m a.s.l. and 1776 m a.s.l. All of them fall in the category of static ice caves, with an almost constant duration of closed periods (in terms of air circulation) and only rare, extremely short-lasting open periods. Using the criterion of the extended duration of ice and snow, we differentiate three types: perennial (4 caves), occasionally perennial (5 caves), and seasonal (18 caves) (Tables 27.1 and 27.2). At the end of the 19th century, 9 out of 11 known ice caves in Eastern Serbia had perennial ice (Cvijić, 1895), and today all of them are only seasonal ice caves. At the present time, no detailed monitoring has been set up in order to systematically keep a record of these changes, but this may be part of future activities (cf. Luetscher et al., 2005). Despite more than 150 years of research, the static ice caves of Serbia are insufficiently explored, both climatically and morphologically. It is necessary to upgrade the methods for data logging and absolute dating, as well as for a multidisciplinary approach (e.g., biospeleological studies of ice caves and their frigophyllic fauna). In the past, ice in Serbian ice caves had economic significance, when it was taken out and used for cooling foods and drinks. With the development of artificial cooling systems, economic interest in these caves has diminished, but the issue of monitoring climate change could put these phenomena in the limelight again.
REFERENCES Boué, A., 1840. La Turkie d'Europe. Arthus Bertrand, Paris 526. p. Boué, A., 1891. Geološka skica evropske Turske (Geological sketch of European Turkey). Translation from French by Jovan Cvijić and Jovan Žujović Geološki anali balkanskog poluostrva (Annales géologiques de la péninsule Balkanique)3, 1–157. (Annex) (in Serbian). Ćalić Ljubojević, J., Ljubojević, V., 1999. Tisova jama (Tisova Jama Cave). Zaštita prirode (Protect. Nat.)51 (2), 27–31 (in Serbian). Ćalić Ljubojević, J., Ljubojević, V., 2000. Caves below collapse dolines—case study of Tisova Jama (Eastern Serbia). Acta Carsol. 29 (2), 95–101. Cvijić, J., 1893. Geografska ispitivanja u oblasti Kučaja u istočnoj Srbiji (Geographic research in the area of Kučaj in Eastern Serbia). Geološki anali balkanskog poluostrva (Annales géologiques de la péninsule Balkanique)5, 7–172 (in Serbian). Cvijić, J., 1895. Pećine i podzemna hidrografija u istočnoj Srbiji (Caves and underground hydrography in Eastern Serbia). Glas Srpske kraljevske akademije nauka 46, 1–101 (in Serbian). Cvijić, J., 1896. Les glacières naturelles de Serbie. Spelunca – Bulletin de la Societé de Spéléologie, II 6–7, 64–77. Cvijić, J., 1924. Geomorfologija. Knjiga prva (Geomorphology. Book One). Državna štamparija, Beograd1–588. (in Serbian).
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Ducić, V., Radovanović, M., 2005. Klima Srbije (The climate of Serbia). Zavod za udžbenike, Beograd. pp. 5–212 (in Serbian). Ford, D.C., Williams, P.W., 2007. Karst Hydrogeology and Geomorphology. John Wiley & Sons, Ltd., Chichester. 562 pp. Gavrilović, D., 1974. Srpska kraška terminologija. Kraška terminologija Jugoslovenskih naroda II (Serbian Karst Terminology. Karst Terminology of Yugoslav Peoples, II). Savez geografskih institucija Jugoslavije, Beograd. pp. 1–73 (in Serbian). Girardot, A., Trouillet, L., 1885. La Glacière de Chaux-les-Passavant. Mémoires de la Société d'Emulation du Doubs 9 (5), 449–524. Jeannel, R., Racovitza, E., 1929. Enumération des Grottes visitées 1918-1927 (7-e série). Biospéologica 54. Archives de Zoologie expérimentale et générale, Paris, Tome 68, fasc. 2. Lazarević, R., 1998. Kras Dubašnice, Gornjana i Majdanpeka – pećine, jame, kraška hidrografija (Karst of Dubašnica, Gornjan and Majdanpek—Caves and Karst Hydrography). Srpsko geografsko društvo (Serbian Geographical Society), Beograd. pp. 1–302 (in Serbian). Luetscher, M., Jeannin, P.-Y., 2004. A process-based classification of alpine ice caves. Theor. Appl. Karstol. 17, 5–10. Luetscher, M., Jeannin, P.-Y., Haeberli, W., 2005. Ice caves as an indicator of winter climate evolution: a case study from the Jura Mountains. The Holocene 15 (7), 982–993. Mačaj, S., 1866. Građa za topografiju okruga Knjaževačkog (Materials for topography of the Knjaževac County). Glasnik Srpskog učenog društva 19, (in Serbian). Milić, Č., 1962. Glavne odlike krasa Suve planine (The main characteristics of Mt. Suva Planina karst). Zbornik radova Geografskog instituta “Jovan Cvijić” SANU (J. Geogr. Inst. “Jovan Cvijić” SASA)18, 93–154 (in Serbian). Milić, Č., 1968. Jame kao indikatori periglacijala u krasu istočne Srbije (Vertical caves as indicators of periglacial environment in the karst of Eastern Serbia). Cvijićev zbornik. SANU, Beograd. pp. 69–81 (in Serbian). Nešić, D., 2001. Kraška morfologija u slivu Toponičke reke [Karst morphology in the drainage area of the Toponička Reka River]. Unpublished M.Sc. Thesis, Faculty of Geography, University of Belgrade, pp. 1–306. Nešić, D., 2002a. Rezultati speleoloških i speleoklimatoloških istraživanja Velikog ledenika na Devici, Rtanjske i Tupižničke ledenice (Results of speleological and speleoclimatological research of the ice caves Veliki Ledenik on Devica Mt, Rtanjska Ledenica and Tupižnička Ledenica). Glasnik Srpskog geografskog društva (Bull. Serbian Geogr. Soc.)82 (2), 45–54. (in Serbian). Nešić, D., 2002b. Led i sneg u speleološkim objektima planinskih područja Srbije i Crne Gore (Ice and snow in the caves of Serbian and Montenegrian mountains). In: Proceedings of the Conference “S planinom u novi vek”, Kopaonik. pp. 89–94 (in Serbian). Nešić, D., 2002c. Ledenice i snežnice Karpato-balkanskih planina istočne Srbije (Ice and snow caves in the Carpathian-Balkan mountains of Eastern Serbia). In: Proceedings of the Conference “Ekološka istina”, Donji Milanovac. pp. 57–61 (in Serbian). Nešić, D., 2015. Results of the speleological exploration on Pešter plateau. Bull. Serbian Geogr. Soc. 95 (4), 1–30. Nešić, D., 2017. Jama Provalija na Suvoj planini (istočna Srbija), primer podzemnog visokoplaninskog karsta (Provalija pit on Suva planina (eastern Serbia), an example of underground high mountain karst). In: Proceedings of the 8th Symposium on Karst Protection, Pirot (in press). Nešić, D., Pavićević, D., Ognjenović, S., 2008a. Rezultati speleomorfoloških i biospeleoloških istraživanja jame Vrtačelje (Ledena Pećina) (Results of speleomorphological and biospeleological explorations of the Vrtačelje Cave—Ledena Pećina). Zaštita prirode (Protect. Nat.)58 (1–2), 15–25. (in Serbian). Nešić, D., Pavićević, D., Petrović, B., Zatezalo, A., 2008b. Rezultati novijih istraživanja Tupižničke ledenice (Results of recent studies of Tupižnička Ledenica). Zaštita prirode (Protect. Nat.)59 (1–2), 67–79. (in Serbian). Petrović, D., 1964. Dve ledenice na Kučaju (Two ice caves on Mt. Kučaj). Glasnik Srpskog geografskog društva (Bull. Serbian Geogr. Soc.)44 (1), 69–73 (in Serbian). Petrović, J., 1976. Jame i pećine SR Srbije (Caves of Serbia). Vojnoizdavački zavod, Beograd pp. 1–511 (in Serbian). Previnac, M.M., 1951. Neke prirodne znamenitosti u karstu istočne Srbije (Several natural phenomena in the karst of Eastern Serbia). Zaštita prirode (Protect. Nat.)2–3, 359–367 (in Serbian).
ICE CAVES IN SERBIA
*
27
Dragan Nešić*, Jelena Ćalić†
Institute for Nature Conservation of Serbia, Niš, Serbia Geographical Institute “Jovan Cvijić” of the Serbian Academy of Sciences and Arts, Belgrade, Serbia†
C HAPTER OUTLINE 27.1 Introduction ................................................................................................................................ 611 27.2 History of Research ..................................................................................................................... 613 27.3 Types of Ice Caves in Serbia ........................................................................................................ 614 27.3.1 Perennial Ice Caves ............................................................................................. 614 27.3.2 Occasionally Perennial Ice Caves .......................................................................... 620 27.3.3 Seasonal Ice Caves .............................................................................................. 621 27.4 Outline of Temperature Dynamics ................................................................................................. 621 27.5 Conclusions ................................................................................................................................ 623 References ........................................................................................................................................... 623
27.1 INTRODUCTION In this chapter, the term “ice caves” refers to both perennial and seasonal ice caves, following the classification of Ford and Williams (2007), as opposed to the stricter classification by Luetscher and Jeannin (2004), which would, taking into account only perennial ice caves, leave Serbia with only four established sites. Considering the fact that in five of the listed ice caves, the ice sometimes lasts the whole year while in some years melts completely, we had to conditionally introduce the term “occasionally perennial,” which in this case lies in-between perennial and seasonal. In the Serbian geomorphology literature, the caves with ice and/or snow are called ledenice (ice caves) and snežnice (snow caves); these words are from the language of the native people, but are accepted in national scientific terminology as well (Gavrilović, 1974). Ice caves at temperate latitudes are usually expected to be located in the zones of relatively cold periglacial alpine environments in high mountain areas above the tree line. However, there are few such areas in Serbia, and most of them do not have an underlying carbonate geology. On the other hand, there are examples where ice and snow tend to accumulate in caves below the tree line for longer than an usual winter season. Such accumulations of subterranean ice are considered to be azonal processes, which are not typical for the given elevation range (zone). Exceptions of this kind are located mainly in the mediumhigh mountains of the Carpatho-Balkan and Dinaric ranges (Fig. 27.1) in Serbia. Locations of the ice caves fall between 670 m a.s.l. and 1776 m a.s.l. Ice Caves. https://doi.org/10.1016/B978-0-12-811739-2.00027-9 © 2018 Elsevier Inc. All rights reserved.
611
612
CHAPTER 27 ICE CAVES IN SERBIA
FIG. 27.1 Spatial distribution of ice caves in Serbia (base map generated from SRTM data).
In general, it can be assumed, based on theory and the majority of literature references, that the ice in the perennial ice caves in Serbia is mostly of relict and endogenic character (formed through congelation of cave waters). Some seasonal ice caves host recent and/or exogenic ice, as well as snow accumulations at the entrances. Long-term observations, despite being very irregular in time, have indicated that ice in the static ice caves in Serbia is mostly formed by freezing of percolation waters and very rarely by concentrated input. Gradual transformation of snow to ice is mostly lacking, except
27.2 HISTORY OF RESEARCH
613
in the case of a unique perennial ice cave in SW Serbia (Lednica, in the village of Krnjača on Ožalj Mountain). High amount of precipitation in the colder parts of the year, and the absolute number of frosty and snowy days, has a significant impact on the quantity of underground ice (Nešić, 2002b).
27.2 HISTORY OF RESEARCH The first observation of an ice cave in Serbia dates back to the first half of the 19th century. French/ Austrian geologist Ami Boué (1840, 1891), during his geological explorations of the “European Turkey,” visited several caves in Serbia. One of them was the Rtanjska Ledenica ice cave on Mt. Rtanj in Eastern Serbia, where he measured the air temperature at the bottom. Mačaj (1866) mentioned the Tupižnička Ledenica ice cave in his general “topographic” overview of the Knjaževac county. The end of the 19th century in Serbian ice cave research was marked with explorations done by the founder of Serbian speleology and karstology, Jovan Cvijić (Cvijić, 1893, 1895, 1896). He gave a rather high hierarchical place to ice caves, within his general classification of caves: (1) “proper” caves (river caves and dry caves), (2) rock shelters, and (3) ice caves.
FIG. 27.2 Jovan Cvijić's sketches of ice caves in Eastern Serbia: (1) Rtanjska Ledenica, on Rtanj Mt.; (2) Stojkova Ledenica, on Kučaj Mt.; and (3) Ledenica u Ždrebici, on Suva Planina Mt. After Cvijić, J., 1895. Pećine i podzemna hidrografija u istočnoj Srbiji (Caves and underground hydrography in Eastern Serbia). Glas Srpske kraljevske akademije nauka, 46, 1–101 (in Serbian).
Cvijić compiled the first list of ice caves in Serbia (there were 11 of them at that time), with smallscale maps (Fig. 27.2) and air temperature measurements. Apart from stressing the prerequisites for the existence of ice caves—specific morphology (cold air traps), drip waters or snow—he suggested three classifications of ice caves: static and dynamic (although he stated that there are no dynamic examples in Serbia), “permanent” (perennial), and “periodic” (seasonal). Morphologically, Cvijić differentiated three types of ice caves: (a) short ice caves resembling rock shelters (mostly of N exposure, thick outside vegetation, mildly inclined single passage), (b) ice caves of “aven” (shaft) type (term borrowed from French; entrance at the bottom of a doline, inclined passage called “stromor,” and an ending small chamber), and (c) ice caves with shaft entrance (straight vertical channel of uniform cross-section descending to a large chamber). Cvijić also mentioned the local inhabitants' perceptions of the ice caves, either as small but valuable water reserves for shepherds on the waterless high karst plateaus or as a
614
CHAPTER 27 ICE CAVES IN SERBIA
potential means for selling ice during the summer, for festivals and fairs. This is how he mentions the visit of Ami Boué to the Rtanjska Ledenica ice cave: Ami Boué visited Rtanjska Ledenica 58 years ago and it is of great importance to present his observations. Accompanied by the Serbian prince Miloš, he visited this ice cave in August 1836 (Die europäische Turkei von A. Boué I Band. Wien 1889, p. 88 – Recueil d'itinéraires dans la Turquie d'Europe par A. Boué, Tome second. Vienne 1854, p. 322). He found a lot of snow and ice in it, and measured the temperature of −2°C in the cave, while the air temperature outside of the cave was 23–24°C. At that time, there were thick woods around the Rtanjska Ledenica, while now it is surrounded mostly by meadows. (Cvijić, 1895)
In the second half of the 20th century, several geomorphologists (Petrović, 1964; Milić, 1968; Petrović, 1976; Lazarević, 1998) studied ice caves to a certain extent, but mostly within the broader analyses of general karst morphology. The beginning of the 21st century brought several new papers on ice caves, based on a series of temperature/humidity measurements, carried out mostly within seasonal dynamics during several years (Nešić, 2002a,b,c, 2017; Nešić et al. 2008a,b). There have been no data logging and no absolute dating of ice so far. Published papers on snow and ice in the underground karst of Serbia have focused mostly on particular scattered examples, but both detailed analytical research and summarizing, synthesis studies are generally lacking.
27.3 TYPES OF ICE CAVES IN SERBIA Based on the length of the extended duration of ice and snow in Serbian caves, the results of explorations and research and the previously mentioned classification criteria, we have identified 27 ice caves in Serbia. Four of them are perennial, five are occasionally perennial, and 18 are seasonal (Tables 27.1 and 27.2). At the time of Cvijić (1895), as many as 9 out of 11 known ice caves were perennial. He wrote, “In the remaining nine caves, the ice is present in July and even later, during the whole summer; they are therefore in the group of permanent ice caves.”
27.3.1 PERENNIAL ICE CAVES Perennial ice and snow occur in only four caves in Serbia, highlighting the rarity and irregularity of underground ice in azonal conditions below the tree line in the medium-high mountains. Three caves of this kind are situated in the Carpatho-Balkan mountains of Eastern Serbia, and one in the Internal Dinarides in southwestern Serbia. In the Carpatho-Balkanides, these caves are Tisova Jama on Beljanica Mountain (1336 m), Mijajlova Jama on Kučaj Mountain, and Provalija on Suva Planina Mountain (1808 m), while the Dinarides host Lednica ice cave, near the village of Krnjača on Ožalj Mountain, close to the border with Montenegro. Tisova Jama is situated in the central part of the high karstified plateau of Beljanica Mountain, with the entrance at 920 m a.s.l. The large cavity consists of a large doline, vertical passage, and a vast inclined chamber, 181 m long and 105 m wide (Fig. 27.3).
Table 27.1 Ice Caves in the Carpatho-Balkan Mountains of Eastern Serbia Entrance Elevation
Length
Depth
180-160
331
10-7
710
15-8
Kučaj Mt.
905
100-30
Zla Ledenica
Kučaj Mt.
900
30-15
150
37
6
Stojkova Ledenica
Kučaj Mt.
865
30-17
150
47
7
Rtanjska Ledenica Ledena Peć
Rtanj Mt.
926
24-9
63
40
Inclined
Beljanica Mt. Kučaj Mt.
670
9-6
108
18
Inclined
850
13-3
105
20
Inclined
Name
Location
1
Tisova Jama
Beljanica Mt.
920
2
Provalija
1649
3 4
Mijajlova Jama Dubašnica
Suva Planina Mt. Kučaj Mt.
5
8 9 10
11
12
Dobra Ledenica Ledenica u Maloj Brezovici Ledenica u Velikoj Brezovici Ledena Pećina
Kučaj Mt.
8
Passage Inclination
Origin of Ice
Duration of Ice/Snow
235
Vertical/ inclined
Snow
Perennial
58
58
Vertical
Snow
Perennial
297
167
Vertical/ inclined Vertical
Percolation water Percolation water Snow
Perennial
276
43
Vertical/ inclined Vertical/ inclined
Inclined
Snow and percolation water Percolation water Percolation water Percolation water Percolation water
Occasionally perennial Occasionally perennial Occasionally perennial Occasionally perennial Seasonal Seasonal Seasonal
Kučaj Mt.
Kučaj Mt. (Vrtačelje)
Source Ćalić Ljubojević and Ljubojević, 2000 Nešić, 2017
Petrović, 1976 cave register Petrović, 1964 Cvijić, 1895
Nešić, 2002a Cvijić, 1895 Petrović, 1964 Cvijić, 1893
Cvijić, 1893
922
5-4
231
92
Inclined/ cascading
Percolation water
Seasonal
Nešić et al., 2008a
615
Continued
27.3 TYPES OF ICE CAVES IN SERBIA
Entrance Dimensions
No
616
Table 27.1 Ice Caves in the Carpatho-Balkan Mountains of Eastern Serbia—cont'd Entrance Dimensions
Name
Location
13
Gaura Đin Šotaća
Kučaj Mt.
800
14
Tupižnica Mt. Devica Mt.
1060
13-11
63
26
1123
22-8
51
25
Devica Mt.
1145
8-4
42
18
Tupižnička Ledenica Veliki Ledenik Mali Ledenik Ledenik kod Sićermanske Livade Ledenik
19
Snežnica
20
Ledenica u Ždrebici
Svrljiške Planine Mt. Suva Planina
21
Krstasta Provalija Ledenica Trem
Suva Planina Suva Planina
15 16 17
22
Length
Depth
10
8.5
Passage Inclination
Origin of Ice
Duration of Ice/Snow
Inclined
Snow and percolation water Percolation water Percolation water Percolation water
Seasonal
Previnac, 1951
Seasonal
Nešić, 2002a
Seasonal
Nešić, 2002a
Seasonal
Nešić, 2001
Inclined/ vertical Inclined Inclined
Devica Mt.
Ozren Mt.
Source
Nešić, 2001
1120
43
20
Inclined
Percolation water
Seasonal
Cvijić, 1924 Cvijić, 1895
1370
18
24
Inclined
Snow and percolation water
Seasonal
Cvijić, 1895
Milić, 1962 1776
10-6
13
2
All dimensions are in meters (m). The numbers in the first column correspond to locations in Fig. 27.1.
Rock shelter
Snow and percolation water
Seasonal
Cvijić, 1895
CHAPTER 27 ICE CAVES IN SERBIA
Entrance Elevation
No
Table 27.2 Ice Caves in the Dinarides of Southwestern Serbia Entrance Dimensions
Krnjača village
1152
8-5
Piskova Poljana (Pešter) Vojselov Bunar (Pešter) Mezgraja (Pešter)
1518
7-3
69
6
Ponor cave
1215
2-10
43
23
Vertical/ inclined
1316
9
40
Vertical/ inclined
1346
1-14
11
Vertical structural cavity
Name
Location
23
Lednica
24
Ledenica
25
Špela Bores
26
Bezdan u Mezgraji
27
Golubova Pećina
Kamena Gora village
Length
37
Depth
All dimensions are in meters (m). The numbers in the first column correspond to locations in Fig. 27.1.
Passage Inclination
Origin of Ice
Duration of Ice/Snow
Vertical/ inclined
Snow and percolation water Percolation and inflow waters Percolation water and snow Percolation water and snow Snow and percolation water
Perennial
Personal observation
Occasionally perennial
Nešić, 2015
Seasonal
Nešić, 2015
Seasonal
Nešić, 2015
Seasonal
Personal observation
Source
27.3 TYPES OF ICE CAVES IN SERBIA
Entrance Elevation
No
617
618
CHAPTER 27 ICE CAVES IN SERBIA
Tisova jama Beljanica, Serbia
0m
A –228 –210
–165
–235 m –203
–165 m
Plan –185 0
50
A
100 m
surveyed by Student Speleologic and Alpinistic Club (ASAK), Belgrade
340° – 160° A –215
N
A –215 m Projected elevations 0
50
100 m
70° – 250°
–235
FIG. 27.3 Cave map of the Tisova Jama. After Ćalić Ljubojević, J., Ljubojević, V., 1999. Tisova jama (Tisova Jama Cave). Zaštita prirode (Protection of Nature), 51 (2), 27–31 (in Serbian); Ćalić Ljubojević, J., Ljubojević, V., 2000. Caves below collapse dolines—case study of Tisova Jama (Eastern Serbia). Acta Carsol. 29 (2), 95–101.
The dimensions of the doline are 160 m by 180 m, with an approximate surface of 9.07 hectares. The total depth, measured from the rim of the doline, is 235 m. At -130 m, where the vertical passage enters the chamber, a large ice-snow accumulation, 50 m long and 10 m thick on average, with approximately 5000 m3 of accumulated ice and snow (Ćalić Ljubojević and Ljubojević, 1999, 2000) is present. The vast doline is the area that collects the snow in winter, from which the snow then slides farther down, like through a funnel. At the bottom of the vertical shaft, morphological conditions are favorable for ice and snow accumulation. It is suspected that the ice from the Tisova Jama dates back to the Little Ice Age (a period of colder climate), but this assumption needs to be checked by absolute dating methods. The difference between the ice quantity in 1988 and 1999, when this cave was twice surveyed, shows a decreasing trend (Ćalić Ljubojević and Ljubojević, 1999, 2000), which can probably be explained by the recent influence of climate changes (as also discussed by Luetscher et al. (2005), who used examples from the Swiss Jura to show the decay of cave ice in the past decades). Mijajlova Jama in the western part of the Kučaj mountains (710 m a.s.l.) is an impressive vertical cave with three entrances and a total depth of 167 m (Petrović, 1976). Through the freezing of percolation waters, ice crusts form on the walls of the shaft, further collapsing at the foot of the vertical drop to form accumulations of crushed ice and debris resembling an underground rock glacier. Suva Planina Mountain (1808 m) is the highest limestone morphostructure within the CarpathoBalkanides of Eastern Serbia and has a vast karst-leveled surface called Valožje (1400–1600 m). This area hosts both relict and recent high-mountain karst, as well as relict periglacial relief. Taking this into account, it is not strange that Provalija Cave (Fig. 27.4), located close to the mountain top (Trem, 1808 m), hosts perennial ice and snow accumulation (Nešić, 2017).
FIG. 27.4 Provalija Ice Cave (1 – Entrance; 2 – Step, pit; 3 – Firn; 4 – Ice; 5 – Terrace with rubble; 6 – Massive limestone). After Nešić, D., 2017. Jama Provalija na Suvoj planini (istočna Srbija), primer podzemnog visokoplaninskog karsta (Provalija pit on Suva planina (eastern Serbia), an example of underground high mountain karst). In: Proceedings of the 8th Symposium on Karst Protection, Pirot (in press).
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CHAPTER 27 ICE CAVES IN SERBIA
This cave is situated in the structural depression Kozija Grbina, SW of the highest peak, at 1649 m a.s.l. It consists of a sub-vertical passage 7–10 m in diameter and 58 m deep, but speleomorphological exploration is not complete yet. At the depth of 30 m, a large accumulation of compact ice is present, with a visible ice thickness of 8–10 m (volume about 385 m3). This is permanent ice with snow cover that fluctuates in thickness with seasonal weather conditions. On Suva Planina Mountain (Valožje plateau), other caves have been detected (e.g., Krstasta Provalija, Savina Propast; Milić, 1962) with indications of prolonged presence of ice and snow, but these phenomena are still insufficiently explored. There is only one known perennial ice cave in the Serbian part of the Dinarides: Lednica Cave in the village of Krnjača on Ožalj Mountain, located on the side of Tmuša sinking river, with entrances at 1152 m a.s.l. This cave is still insufficiently explored and has not been surveyed, but the first indications point out that one of the main factors of ice formation is the accumulation of snow. Below the entrances, the cave passage is inclined and covered with compact ice on a length of about 50 m. It seems that in the conditions of seasonal partial melt, the meltwater freezes again at the contact with the ice below. At the bottom of the cave a spacious chamber is present, which is the zone of cool air concentration. The climate of Lednica can be linked to its climatic context, with precipitation amounts in this part of the Dinarides exceeding 1000 mm (Ducić and Radovanović, 2005).
27.3.2 OCCASIONALLY PERENNIAL ICE CAVES Long-term observations, although at irregular intervals, especially during the last decade of the 20th century and since, have shown that there are several caves where ice lasts the whole year or longer, sometimes interrupted by periods without summer ice. For these ice caves, we have conditionally accepted the term “occasionally perennial ice caves.” Representatives of this group are Zla Ledenica, Stojkova Ledenica, and Dubašnica on Kučaj Mountain, Rtanjska (Mužinačka) Ledenica on Rtanj Mountain (Carpatho-Balkanides), as well as the Ledenica ice cave on the Pešter plateau in the Dinarides of southwestern Serbia. The data on Zla Ledenica (alternative name in Vlach language: Gaura Rea) are very scarce— just one source. Petrović (1964) published a short note about it, together with the nearby seasonal ice cave Dobra Ledenica (Gaura Bună). At the time of Petrović's explorations, in September 1962, there was an accumulation of ice and snow that probably, at least that year, lasted all year. However, personal contacts with the local population and hunters who visit the area, indicate that in recent years there has been no ice in Zla Ledenica, which must be taken conditionally because it was not verified. Stojkova Ledenica on the karst-leveled surface of Dubašnica in the eastern part of Kučaj Mountain was first explored and mapped by Cvijić (1895), then subsequently was visited by Jeannel and Racovitza (1929) within a biospeleological study, and in the second half of 20th century was remapped by Lazarević (1998). This is a large karst cavern whose entrance was formed by collapse. At the times of Cvijić and Lazarević, the cave was reported as having perennial ice, but in recent visits no ice was present in early autumn (Nešić, 2006, pers. comm.) Dubašnica Cave, also situated on eastern Kučaj, is the second deepest cave in Serbia (−276 m). Being almost completely a vertical pit, it is occasionally visited by caving teams for sports reasons, but unfortunately measurements of temperatures were never properly organized or published. The teams reported finding ice in summer months, but there were also years without deposited ice or snow.
27.4 OUTLINE OF TEMPERATURE DYNAMICS
621
The entrance to Rtanjska Ledenica on Rtanj Mountain, lies at an elevation of 926 m a.s.l. It is an example of a static ice cave with an inclined, 63-meter-long passage that reaches a maximum depth of 40 m. Freezing of percolation waters contribute greatly to the ice balance. In some years, the ice deposits exist during the summer and are continuous throughout the year or for several consecutive years. One such case was recorded in autumn 2004, when there was about 1 m3 of ice. Relatively detailed air temperature measurements (not data logging) were carried out in 1997 (Nešić, 2002a). Ami Boué visited this cave in 1836 and later wrote, “In Cretaceous limestones, natural shafts are also frequent, although they are rarely so nicely characterized as in the case of Ledenica, in the woods on the southern slopes of Mt. Rtanj” (Boué, 1891). Observations of the Ledenica Cave, located in the Žilindar-Kruščica area on the Pešter plateau in SW Serbia, fit well with what was written about occasionally perennial ice caves. Here, ice is formed by freezing of percolation and surface inflow water, as this cave is fed by a short ponor stream. On April 26, 2008, the whole surface of the cave was covered by an ice sheet 0.5–1 m thick, with a total volume of 40–50 m3, which by October 16, 2008, was reduced to 4.3 m3 (Nešić, 2015). This observation places the cave in the category of occasionally perennial ice cave, considering also the fact that during the explorations in the autumn of 2007, there was no ice at all.
27.3.3 SEASONAL ICE CAVES All other caves with ice and snow in the Serbian karst (Tables 27.1 and 27.2) are seasonal static ice caves, with annual renewal of ice and/or snow deposits, these lasting longer than snow outside the caves. The ice is primarily formed by freezing of percolation waters, and occasionally by snow firnification. In the seasonal static ice caves of Serbia, ice melts under the influence of heat advected by warm drip waters—reverse process than during formation of ice deposits—as well as the general warming of air, bedrock, and infills. The maximum recorded warming compared with the winter temperatures in these ice caves was 5.5°C (Nešić, 2002a). It can be concluded that seasonal ice caves are the dominant type of ice caves in the Serbian karst. On average, snow and ice in these caves lasts about 6–8 months per year, depending on weather conditions.
27.4 OUTLINE OF TEMPERATURE DYNAMICS There have been relatively few attempts to explain the climatic functioning of azonal static ice caves in Serbia (Cvijić, 1895; Nešić, 2002a). Measurements of cave climate parameters were carried out in Rtanjska Ledenica, Tupižnička Ledenica, and Veliki Ledenik caves on Devica Mountain. These measurements were done using the simple mercury thermometer (0.2°C precision), mounted on a tripod 1 m above the ground. Data loggers were not available. The results pointed to the regularity of permanent minimal negative air temperatures inside the ice caves (–0.2°C to –0.8°C) while outside temperatures were up to 6°C to 7°C, or very cold air from 0.4°C to 1.2°C, with outside temperatures of 14.8°C to 21.3°C (Nešić, 2002a; Nešić et al., 2008b). This climatic condition of permanent concentration of cold air in ice caves is called the “closed period” (e.g., Girardot and Trouillet, 1885, cited by Luetscher and Jeannin, 2004; Cvijić, 1895), which in present climatic conditions in Serbia occurs throughout most of the year (Fig. 27.5A and B). Inversion of air temperatures in the static ice caves was recorded during periods with outside negative air temperatures, while inside the ice caves
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(although with temperatures below zero), the temperature was several degrees warmer. This was recorded in Tupižnička Ledenica on January 9, 1997, when the temperature was −2.9°C outside the cave and −1.5°C inside the cave.
FIG. 27.5 Climatic functioning of the static ice cave Veliki Ledenik on Devica Mt.: (A, B) long-lasting static functioning (“closed period”) without noticeable air circulation; (C) extremely short-lasting dynamic moment, with observed and measured sudden inflow of cold air from the outside (“open period”); and (D) static phase, without noticeable air circulation, but with expected subsequent air inflow because of the difference in temperature (the moment was not observed in the field on a given date, but suspected).
More detailed observations were made in the Veliki Ledenik ice cave on Devica Mountain. On December 31, 1999, it was −6.2°C outside and −4.4°C inside, and on January 1, 2000, it was −8.8°C outside and −6.3°C inside (Nešić, 2002a) (Fig. 27.5D). This means that azonal ice caves may have a closed period even during temperature inversions. On the other hand, the same cave showed the dynamic characteristics typical for the open period on January 25, 1997. D. Nešić was carrying out temperature measurements in the cave during the temperature inversion, and exactly as he was taking the measurement, a sudden inflow of cold air caused a wind-like effect, with a temperature drop of 1.6°C (Fig. 27.5C). Based on a number of observations of climate conditions in ice caves and making top/bottom air temperature profiles, we came to the conclusion that the short open period of static ice caves, which refers to the inflow of cold air during the winter, should be linked only to the rare conditions of a sudden drop in the outside temperature on winter nights, whereas in general the main climatic characteristics of this type of ice cave remain unchanged (Nešić, 2002a).
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27.5 CONCLUSIONS Azonal static ice caves in Serbia are caves with permanent presence of cold air, which is, apart from the general climatic and weather conditions in the mountains below the tree line, mostly conditioned by the geometry of the caves. The most usual types are shallow inclined caves where the underground chambers are positioned laterally in relation to the mostly spacious entrances. This arrangement enables the formation of cold air traps, additionally helped by northerly exposed entrances, as well as by thick vegetation in their immediate surroundings, protecting them from direct sunlight. Ice caves in Serbia are distributed in an elevation belt between 670 m a.s.l. and 1776 m a.s.l. All of them fall in the category of static ice caves, with an almost constant duration of closed periods (in terms of air circulation) and only rare, extremely short-lasting open periods. Using the criterion of the extended duration of ice and snow, we differentiate three types: perennial (4 caves), occasionally perennial (5 caves), and seasonal (18 caves) (Tables 27.1 and 27.2). At the end of the 19th century, 9 out of 11 known ice caves in Eastern Serbia had perennial ice (Cvijić, 1895), and today all of them are only seasonal ice caves. At the present time, no detailed monitoring has been set up in order to systematically keep a record of these changes, but this may be part of future activities (cf. Luetscher et al., 2005). Despite more than 150 years of research, the static ice caves of Serbia are insufficiently explored, both climatically and morphologically. It is necessary to upgrade the methods for data logging and absolute dating, as well as for a multidisciplinary approach (e.g., biospeleological studies of ice caves and their frigophyllic fauna). In the past, ice in Serbian ice caves had economic significance, when it was taken out and used for cooling foods and drinks. With the development of artificial cooling systems, economic interest in these caves has diminished, but the issue of monitoring climate change could put these phenomena in the limelight again.
REFERENCES Boué, A., 1840. La Turkie d'Europe. Arthus Bertrand, Paris 526. p. Boué, A., 1891. Geološka skica evropske Turske (Geological sketch of European Turkey). Translation from French by Jovan Cvijić and Jovan Žujović Geološki anali balkanskog poluostrva (Annales géologiques de la péninsule Balkanique)3, 1–157. (Annex) (in Serbian). Ćalić Ljubojević, J., Ljubojević, V., 1999. Tisova jama (Tisova Jama Cave). Zaštita prirode (Protect. Nat.)51 (2), 27–31 (in Serbian). Ćalić Ljubojević, J., Ljubojević, V., 2000. Caves below collapse dolines—case study of Tisova Jama (Eastern Serbia). Acta Carsol. 29 (2), 95–101. Cvijić, J., 1893. Geografska ispitivanja u oblasti Kučaja u istočnoj Srbiji (Geographic research in the area of Kučaj in Eastern Serbia). Geološki anali balkanskog poluostrva (Annales géologiques de la péninsule Balkanique)5, 7–172 (in Serbian). Cvijić, J., 1895. Pećine i podzemna hidrografija u istočnoj Srbiji (Caves and underground hydrography in Eastern Serbia). Glas Srpske kraljevske akademije nauka 46, 1–101 (in Serbian). Cvijić, J., 1896. Les glacières naturelles de Serbie. Spelunca – Bulletin de la Societé de Spéléologie, II 6–7, 64–77. Cvijić, J., 1924. Geomorfologija. Knjiga prva (Geomorphology. Book One). Državna štamparija, Beograd1–588. (in Serbian).
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Ducić, V., Radovanović, M., 2005. Klima Srbije (The climate of Serbia). Zavod za udžbenike, Beograd. pp. 5–212 (in Serbian). Ford, D.C., Williams, P.W., 2007. Karst Hydrogeology and Geomorphology. John Wiley & Sons, Ltd., Chichester. 562 pp. Gavrilović, D., 1974. Srpska kraška terminologija. Kraška terminologija Jugoslovenskih naroda II (Serbian Karst Terminology. Karst Terminology of Yugoslav Peoples, II). Savez geografskih institucija Jugoslavije, Beograd. pp. 1–73 (in Serbian). Girardot, A., Trouillet, L., 1885. La Glacière de Chaux-les-Passavant. Mémoires de la Société d'Emulation du Doubs 9 (5), 449–524. Jeannel, R., Racovitza, E., 1929. Enumération des Grottes visitées 1918-1927 (7-e série). Biospéologica 54. Archives de Zoologie expérimentale et générale, Paris, Tome 68, fasc. 2. Lazarević, R., 1998. Kras Dubašnice, Gornjana i Majdanpeka – pećine, jame, kraška hidrografija (Karst of Dubašnica, Gornjan and Majdanpek—Caves and Karst Hydrography). Srpsko geografsko društvo (Serbian Geographical Society), Beograd. pp. 1–302 (in Serbian). Luetscher, M., Jeannin, P.-Y., 2004. A process-based classification of alpine ice caves. Theor. Appl. Karstol. 17, 5–10. Luetscher, M., Jeannin, P.-Y., Haeberli, W., 2005. Ice caves as an indicator of winter climate evolution: a case study from the Jura Mountains. The Holocene 15 (7), 982–993. Mačaj, S., 1866. Građa za topografiju okruga Knjaževačkog (Materials for topography of the Knjaževac County). Glasnik Srpskog učenog društva 19, (in Serbian). Milić, Č., 1962. Glavne odlike krasa Suve planine (The main characteristics of Mt. Suva Planina karst). Zbornik radova Geografskog instituta “Jovan Cvijić” SANU (J. Geogr. Inst. “Jovan Cvijić” SASA)18, 93–154 (in Serbian). Milić, Č., 1968. Jame kao indikatori periglacijala u krasu istočne Srbije (Vertical caves as indicators of periglacial environment in the karst of Eastern Serbia). Cvijićev zbornik. SANU, Beograd. pp. 69–81 (in Serbian). Nešić, D., 2001. Kraška morfologija u slivu Toponičke reke [Karst morphology in the drainage area of the Toponička Reka River]. Unpublished M.Sc. Thesis, Faculty of Geography, University of Belgrade, pp. 1–306. Nešić, D., 2002a. Rezultati speleoloških i speleoklimatoloških istraživanja Velikog ledenika na Devici, Rtanjske i Tupižničke ledenice (Results of speleological and speleoclimatological research of the ice caves Veliki Ledenik on Devica Mt, Rtanjska Ledenica and Tupižnička Ledenica). Glasnik Srpskog geografskog društva (Bull. Serbian Geogr. Soc.)82 (2), 45–54. (in Serbian). Nešić, D., 2002b. Led i sneg u speleološkim objektima planinskih područja Srbije i Crne Gore (Ice and snow in the caves of Serbian and Montenegrian mountains). In: Proceedings of the Conference “S planinom u novi vek”, Kopaonik. pp. 89–94 (in Serbian). Nešić, D., 2002c. Ledenice i snežnice Karpato-balkanskih planina istočne Srbije (Ice and snow caves in the Carpathian-Balkan mountains of Eastern Serbia). In: Proceedings of the Conference “Ekološka istina”, Donji Milanovac. pp. 57–61 (in Serbian). Nešić, D., 2015. Results of the speleological exploration on Pešter plateau. Bull. Serbian Geogr. Soc. 95 (4), 1–30. Nešić, D., 2017. Jama Provalija na Suvoj planini (istočna Srbija), primer podzemnog visokoplaninskog karsta (Provalija pit on Suva planina (eastern Serbia), an example of underground high mountain karst). In: Proceedings of the 8th Symposium on Karst Protection, Pirot (in press). Nešić, D., Pavićević, D., Ognjenović, S., 2008a. Rezultati speleomorfoloških i biospeleoloških istraživanja jame Vrtačelje (Ledena Pećina) (Results of speleomorphological and biospeleological explorations of the Vrtačelje Cave—Ledena Pećina). Zaštita prirode (Protect. Nat.)58 (1–2), 15–25. (in Serbian). Nešić, D., Pavićević, D., Petrović, B., Zatezalo, A., 2008b. Rezultati novijih istraživanja Tupižničke ledenice (Results of recent studies of Tupižnička Ledenica). Zaštita prirode (Protect. Nat.)59 (1–2), 67–79. (in Serbian). Petrović, D., 1964. Dve ledenice na Kučaju (Two ice caves on Mt. Kučaj). Glasnik Srpskog geografskog društva (Bull. Serbian Geogr. Soc.)44 (1), 69–73 (in Serbian). Petrović, J., 1976. Jame i pećine SR Srbije (Caves of Serbia). Vojnoizdavački zavod, Beograd pp. 1–511 (in Serbian). Previnac, M.M., 1951. Neke prirodne znamenitosti u karstu istočne Srbije (Several natural phenomena in the karst of Eastern Serbia). Zaštita prirode (Protect. Nat.)2–3, 359–367 (in Serbian).