In the Croatian Karst Area
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GEOLOŠKI VJESNIK 44 289 - 300 1 Pl. 4 Figs. ZAGREB 1991 MORPHOLOGICAL AND HYDROGEOLOG ICAL CLASSIFICATION OF SPELEOLOGICAL STRUCT URES (CA VES AND PITS) IN T HE CROATIAN KARST AREA Mladen GARA Š I Ć Key words: spcleology, karsL hydrogeology. karst Klju č n e r i ječ i : speleologija, hidrogeologija krša, morphology, caves, shafts, pits, Croatian karst area. morfologija krša, spilje, jame, Hrvatski krš. This papcr dcals wi1h spclcological classification according 10 Na temelju podataka istraženih spelcoloških objekata u krškom the main channcl inclination (cavcs and piu - combined or complex}, području llrvalskc, a uzimajući u obzir spclcomorfološkc i lo morphology (simplc, branching, lcvcl, knce formcd and systcms) spcleohidrogcološkc faktore daje se klasifikacija spcleololkih'Ohjekaia and according lo 1hc hydrogcolog1cal function (pennancnl and pe· prema nag1hu glavnog kanala (spllJC, Jame i kombiniram Lli kompleksm), riodical springs. pcmlanenl and periodical sinkholes. eslllvclas, vruljas prema morfologiji (jednostavni, razgranati, ctam1,koljeničas 1i i sustavni) and pcrcolaling objcc1s). It is based on the dala obtained from some i prema hidrogeološkoj funkciji (stalni i povremeni izvori, stalni i prcviously invcstigatcd spcleological objecls in the karslic urca of povremeni ponori, estavcle, vruljc i proiočni) . Croatia and on the analysis of relevant speleohydrogeological and speleomorphological faclors. 1. INTRO DUCTION from which itoriginatcs (MOORE & SULLIV AN, 1978), on the intensity and type of tcctonic activity, thc un Several different classifications of spclcological dcrground water activity, lhc karslification rate and, finally objects have been made up to now. Unfortunately, in on spclcogcncsis (ALBOY, 1975, GARAŠ I Ć , 1989a, consistencies of some classifications havc resulted in 1989b, JASINSKI, 1966). the appcarance of sevcral criLcria within a single division 2.1. TYPES OF SPELEOLOGICAL OBJECTS wh ich in turn gavc rise to diffcrcnt inLerpretations and provokcd confusion among spcleologists and Whilc studying thc features of caves in the Croatian hydrogcologists. For cxamplc, the division into caves, (Dinaric) karst (GARAŠIĆ, 1986, 1987, GARAŠIĆ & pits, "ice holcs" and potholcs in itsclf contains classi CVIJANOVIĆ, 1985, 1986). It was noticed that thcir fication according to thc main channcl inclination (caves, most correct division was bascd on the main channcl piLs), according to hydrogcological function (potholcs), inclination (ČEPELAK & GARAŠIĆ, 1982) sincc, in according to the physical condition of materials in a this way, thc speleological objccts, i.e. ali cavitics in particular object (icc, snow) and, finally according to thc Earth's crust in which a man can bc physically prescnt local names. (CURL, 1964,GYOZDECKIJ, 1981),couldbcdividcd The intcntion was to create an univcrsal classifi into caves and pits. It is essential (according to UIS - cation of speleological objects using spcleomorphologic Union International dc Spclcologic) that caves must bc and spclcohydrogeologic criteria. Furthermore, numerous over 10 meters long, while the depth ofpits should cxcccd cxarnplcs of objccts invcstigatcd in thc Croatian karst 5 mcters. Smallcr objccts are classificd only cxccptionally could nol have bcen avoided. Thcsc classifications can if thcy are charactcrized by some specific features (e.g., bc applicd in ali karst zones of thc world (dcspitc dif if they are found in rocks wherc thcir occurrcnce is ferent speleogencsis, tcctonics, lithostratigraphy etc.). not normally cxpcctcd or if thcy are the collapsed parts Classifications of spclcological objccts madc in 1976 of some greatcr objects, etc.). and 1982 (ČEPELAK & GARAŠ I Ć, 1982) servcd as Other classifications, c.g. imo caves, pits, potholcs, thc staning point for this investigation. "ice holes", sinkholcs, ctc. could not have been rcgardcd as thc most appropriate solution since several critcria 2. SPELEOMORPIIOLOGICAL CRITERIA wcre adopted in a single division. Thc same applicd for Lhe classification due to !oca! names such as zvckaras, Thc shape of a speleological object (cave) depcnds bczdankas, scmicavcs, potholcs, pits„. etc. as thcse names on lithologic and stratigraphic charactcristics of thc rocks are in fact synonyms for thc same typc of spclco-fcaturcs. raculiy of Civil Enginccring. University of Zagreb, Department of Geotcchnical Eng., Kačićeva 26, CR0-41000,Zagreb rakultel građevinskih znanosti, Sveučilište u Zagrebu, Građevinski institut, Zavod za gcolehniku, Kač i ćeva 26, 41000 Zagreb, Hrvatska 290 Geolollci vjesnik 44 Horizonlal speleo-featurcs in Croatia are most 2.1.2. Pits commonly formed in zones of slightly inclincd bcdded Pits are vcrtical or inclined spcleo - fcatures (in rocks, along horizonta! longitudinal fauhs or, less clination from 45" to 90· -rise of dip) (BURKE & BIRD, frequently, next to nappes. 1966). ln the karst rcgion of Croatia the number of V crtica I speleo-features encountered in Croatia are registered pits predominates over the number of caves usually found near deep reverse faul ts, antic lines and ( 363 1 pits cca 69%). Some examples are: Golubnjača ovenumed beds and folds. = pit (Podlapac, Lika), pit callcd "Jama na Kamenitom Over 6000 speleological objects (caves) are reg vršku" (Delnice, Gorski Kotar), Martineza pit (Buje, istered in CroaiLan karst region (Figure 1.) ancl thc dala Istra), Brgud pit (Dragozeti ći, The Island ofCres), Vilim for 5263 of such objects are considcred in this paper pit (Lokvice, Mt.Biokovo), Trogrla pil (Mt. Dinara), (i.e. dimensions, strikes, forms, types, gcological and Duple pits (Z mi ć i, Mt. Velika Kapela), Durinka pit hydrogeological characteristics, etc.). (Kosinj, Lika), Jama u gaju (Kozalj vrh, Kordun) ... the Lota! of 3631 pits. Their distribution is unequal in different karst ar eas of Croatia. Pits accounL for 76% of ali spcleo -fca tures in the Outer (Adriatic) Karst belt. and for approx. 30% of such fea tures encountered in the Inner Karst belt. On some localities, pits are almost the only speleo-fcaturcs, i.e. at Štirovača on Mt. Vclebit, Mt. Velika Kapela, on the island of Brač. Pirkovača pit (Lađena. Mt. Biokovo) from thc Outer Kam belt is O SOk:n prcsentcd in SUPIČIĆ ( 1981) work. According to thc --~... shape and distribution of the main and sccondary channcls, pits can bc: simplc, branching, step !ike pits and pit systems. AORIATC SEA 2.1.3. Combined or complex speleological objects JADRANSKO MORE IL is sometimcs vcry difficult or a Imo st impossiblc to dcfine the charactcr (type) of a speleo-feature. An object may be a combination of vcnical and honzon tal speleo-fca1urcs whcrc no single fcature 1s prcdominant (FENELON, 1974, BOGU, 1980, GEZE, 1965, Ftg. I. - Croatian karst area in which spelcologica.1 obJCcls are located with lnncr, Middle and Outer kam 1.one or rcg1on AUDETAT, 1981). For instance, a speleo-fcaturc wilh Sltka I. - Područje hrvatskog krša u kojemu se nala1.e speleološkt a venical entrancc (pit) may continuc as a cave, while objekti s unutrašnjim, središnjim i vanj~kim krškim pojasom a spclco-feature with the horizonta! cntrance (cave) may 2.1.1. Caves continue as a pil (TRIMMEL, 1968, TROMBE, 1973). If vertical and horizonLal dimensions are more or lcss Caves are one type of such speleo-fcatures (KYRLE, equal, it is impossible Lo dcfine Lhe Lype of a 1923, FORD & CULLINGFORD, 1976) wherc the main spcleo-fcature. ln such ca')CS, wc are dcaling wilh complex channel is slightly inclined or horizomal. Thcoretically, or combined spclco-femures. Such objects account for caves include all objects whose main channel is inelincd approx. 2% ( I06) of ali objects found in the Croatian from O to 45• (rise or dip) (RENAUL T, 1970, karst and thcy are linkcd to the Inner and Middle Karst MARTINOFF, 1976). About 29% ( 1526) of ali bclt. Some examples are: "Mijatova jama" pit (Mateško spelco-fcatures encountered in the Croatian karst re selo, Kordun), Kojina cave (Furjan, Kordun), Zak.ični ca gion are horizonta! spelco fcaturcs. Some examples are: VII pit (Mt. Medvednica, Zagreb), "Vrbanova peć" Cave Drljića Cave (Pažarište, Lika), Dančinova Cave (Raduč , (Lovinac, Lika) ... total: 106 caves. Lika), PCclina Cavc ( Mogorić, Lika). Vcternica The complex spclcological object of Mijatova pil (Medvednica, Zagreb), Cave Lipa (Lokve, Gorski Kotar), (Mateško selo, Kordun) from the Inner Karst belt is Kuštrovka (G.Dubrave, Kordun) ... total : 1526 caves. presented in GARAŠIĆ, 1980). The arrangement of cavcs in relation to hydro gcologic regionalization is differcnt for individua! karst 2.2. MORPHOLOGICAL TYPES OF SPELEO regions (HERAK, 1976, 1984, 1986). In other words, LOGICAL OBJECTS most of lhc caves in Croatia are situated in the lnner Karst region (over 65%), while they are less frequent Types of speleo-features called morphologic types in the Outcr Karst region (about 24%). Caves are dis may be diffcrentialecl according to the shapc and dis tinguished according to the arrangement of the main tribution of channels in spclcological objects. channel and side channels: simple caves, dendritic caves, After analysing thc cli stribution of different lcvel (etagc) caves and cave systcms. morphologic types of spclcological objccts in the Croatian Garašić : Morphological and Hydrogeological... 291 karst, it is possiblc to conclude that simple pits and caves generally predominate in the Outer Karst belt (Istra, lslands, Mt. Velebit, Mt. Biokovo) and branching spclco features appcar at points where sevcral joint system meet (espccially in the Inner