Morphological and Hydrological Features of Caves and Pits

Morphological and Hydrological Features

    As underground karst landforms with horizontal disposal of passages, caves are dominant in Serbia among phenomena isolated on the basis of the indicated criteria and methodology.
    They are most often composed of several galleries on different levels marking phases in their development, which is to say that the development of most caves passed through several phases. Of the total number of caves, only a few (those numbered 34, 35, and 40 in the present Atlas) are without a cave stream. In caves with a stream, ones where the latter is formed on the impermeable base are dominant. On contact with limestones, they sink to build cave galleries. Most cave streams are periodic or temporary (caves 11, 15, 19, 32, 41, 49, 50, 56, and 59), and only in certain caves are the streams permanent (caves 7, 10, 13, and 54). In a smaller number of cases, permanent cave streams are recorded in the lowest galleries, but sometimes do not emerge, sinking periodically or temporarily instead (caves 2, 6, 9, 24, 26, 28, and 31). Such a hydrological situation indicates that the underground streams in most caves have not reached the impermeable base, and that the karst process is still advancing in depth. Most caves were created by erosion caused by cave streams that were formed under conditions of different pluviometric regimes, when precipitation was considerably more copious. The presence of several phases in their creation not only is a consequence of structural-tectonic relations inside the limestone mass and fluctuations of the erosive base, but also results from significant fluctuations of underground currents or sinking streams.
    A smaller number of caves are composed of several galleries on the same level. They were created during the same evolutionary phase. A main gallery is dominant in these caves, which also contain several lateral galleries. Two groups of caves are distinguished here. Caves of the first group are dry, without a cave stream. They are built in limestones where the karstification process has advanced to the point that the hydrologically active parts have sunk to a deep level below the cave galleries. The entrances to such caves are high above valley bottoms and sites of present-day exsurgence of underground streams. Processes of chemical and mechanical accumulation are dominant in them (caves 39, 76, and 57). These caves are significant for paleontological and archaeological findings. The second group includes caves with periodic and temporary cave streams, regardless of whether galleries are in the inflow part or the outflow part (caves 8, 12, 14, 16, 29, 31, 54, 55, 61, 64, and 73). In certain cases, lateral galleries have assumed the main hydrological function. Permanent water currents flow through them, whereas water flows through the main gallery only during the pluviometric maximum. The present-day hydrological relations in galleries are a consequence of shifting and divergence of cave streams. Owing to reduced inflow of water of a sinking stream formed due to climatic changes, water does not flow through all galleries the whole year long, but rather only during the wet season.
    Caves with one gallery are the least common. In the event that their entrance has considerable relative height, they are caves without a stream, but with significant accumulative processes (caves 36, 37, 39, 57, and 76). If they are on the level of a river bed, then weak or strong streams emerge from them constantly or periodically (caves 1, 18, 20, 51, 52, and 53).
    Pits (underground phenomena with dominant vertical channel disposal) are considerably less common than caves.
    Pits composed of one channel are dominant. Stream erosion had no influence in their formation (caves 25, 68, and 75). Pits with several channels on one or different levels are rarely encountered. This means that most pits arose during one evolutionary phase, more rarely in the course of several.
    The karst of Serbia is characterized by many karst springs of the vauclusian type with maximal discharge of several tens of cubic meters per second. The latest speleological and diving research indicates that these are siphon pits from which streams constantly emerge (caves 60 and 62).
    Pits into which streams sink at present or sank in the past are composed of several channels on different levels. The outflow of these streams is oriented in certain dominant directions of cave development. For various reasons (changes of the erosive base, uneven erodibility of the limestone, tectonic and neotectonic movements, processes of accumulation), the streams undergo horizontal or vertical shifting with the passage of time. This causes formation of channels belonging to different evolutionary phases (caves 58 and 65). Portions of underground streams are found in pits that cut the limestone mass to parts which reach the impermeable base or groundwater level (caves 42 and 65).
    Phenomena with a combined direction of passage disposal (vertical and horizontal) are considerably better represented than pits. This group includes caves which in certain parts have vertical pit-like channels of considerable depth (caves 4, 21, 22, 23, 30, 33, 47, and 48); pits that in certain segments pass over into caves (caves 3, 5, 27, 38, 44, 45, 46, 63, and 66); and caves with galleries on several levels interconnected by vertical channels (No. 43). A smaller number of caves are composed of a single gallery, the remainder of several galleries on different levels. They arose in the course of several phases of development. Except for a few without a cave stream (caves 22, 27, 43, 47, and 63), the remaining caves are characterized by streams that constantly, periodically, or temporarily flow in or out of them (caves 3, 4, 5, 21, 23, 30, 33, 38, 45, 46, 48, and 66).
    Rarer are caves that are passable to man throughout their entire length from the entrance at the stream-sink to the spring entrance. These are caves with horizontal and combined disposal of passages. They were built by streams that sink on contact with limestones, flow through the caves, and emerge on the other side. By virtue of favorable structural, neotectonic, erosive-accumulative, hydrological, and other conditions, the galleries of such caves permit human movement over their whole length. A smaller number of them are dry (caves 17 and 43), but cave streams flow through them temporarily in the majority of cases (caves 3, 4, 15, 18, 23, 29, 33, and 41).
    The length and depth of caves, pits, or underground landforms with combined slope of passages constitute their most conspicuous morphological feature. More than 1,200 caves have been explored in Serbia to date, but only a smaller number of them have a length of more than 500 m (they are all included in the Atlas). There are 30 caves with length of from 500 to 1,000 m, 14 are more than 1,000 m long, and only three of these are longer than 5 km.
    Sixteen pits deeper than 100 m are included in the Atlas. Although there are about 10 to 15 such pits in Serbia, none of them are deeper than abuot 100 m. Because of the great depth and inclination of passages, some caves also have considerable depth, but it nowhere exceeds the indicated maxima (cave 24).
    Shallow karst of the contact type is developed in Serbia. Isolated limestone masses of smaller area are dominant here. For this reason, the caves that have been created are shorter and the pits shallower than in other karst regions of the world.
    It should be added that even after more than 100 years of exploration, little is known about the morphometry of caves and pits in Serbia. It can be expected that future exploration will reveal the fusion of separate caves into large speleological systems of considerable depth. The depths achieved by pits are within boundaries permitted by structural relations of carbonate masses, although certain breakthroughs are possible.

Longest caves and deepest pits

N°	Number of cave	Name of cave	Length/depth (m)
1	23	Usacki pecinski sistem	6185
2	9	Bogovinska pecina	5842
3	24	Provalija	5730
4	4	Samar	3167
5	30	Buronov ponor	2400
6	10	Rajkova pecina	2304
7	32	Pogana pec	2000
8	29	Velika pecina	1960
9	15	Tubica pecina	1929
10	6	Lazareva pecina	1721
11	52	Pipalska pecina	1712
12	13	Stopica pecina	1594
13	3	Vetrena dupka	1450
14	2	Radavacka pecina	1420
15	28	Pecina Bukovik	1402
16	16	Dudiceva pecina	1386
17	12	Mermerna pecina	1260
18	8	Ravanicka pecina	1049
19	17	Vernjikica	1015
20	50	Plandiste	986
21	37	Kovacevica pecina	985
22	33	Jezava	888
23	19	Radanova pecina	857
24	11	Ceremosnja	775
25	53	Jamina	759
26	18	Valja fundata	740
27	40	Hajducica	728
28	55	Vasiljeva pecina	691
29	31	Renesansa	671
30	1	Velika pecina	663
31	22	Vladikina ploca	660
32	43	Ududoj	645
33	26	Vlaska pecina	630
34	36	Popsicka pecina	620
35	64	Bazdarska pecina	617
36	14	Ilinska pecina	584
37	7	Petnicka pecina	580
38	27	Velika atula	560
39	21	Rcanska pecina	556
40	49	Potpec	550
41	54	Gradasnica	529
42	73	Veliki ponor	526
43	61	Ponor Vinjace	522
44	51	Deguricka pecina	520
45	41	Seselacka pecura	516
46	59	Lisicja jama	510
47	35	Resavska pecina	447
48	34	Prekonoska pecina	435
49	57	Canetova pecina	424
50	39	Hadzi-Prodanova pecina	420
51	56	Pecina na vrelu Grze	385
52	20	Ponor	200
1	76	Jama Dubasnica	/-276
2	66	Jama u Lanistu	/-272
3	65	Rakin ponor	/-256
4	46	Ibrin ponor	/-239
5	63	Tisova jama	/-235
6	38	Nemacki ponor	/-204
7	42	Dragov ponor	/-200
8	67	Jama u Velikom Igristu	/-171
9	68	Mijajlova jama	/-167
10	44	Jama u Jalov del	/-166
11	5	Ivkov ponor	/-163
12	48	Fufa	/-140
13	45	Suvi ponor	/-133
14	47	Lencina	/-124
15	58	Ponor kod Cekove kuce	/-118
16	60	Krupacko vrelo	/-83
17	62	Vrelo Mlave	/-73