Istra\u017eivanja \u0161pilja na podru\u010dju slapa Miljacka po\u010dela su sedamdesetih godina pro\u0161loga stolje\u0107a. Na veliku perspektivu za nastavak istra\u017eivanja \u0161pilje Miljacka IV, osobito glavnoga kanala, ukazao je rezultat zadnjeg istra\u017eivanja, koje je stalo u prostranom kanalu na 15 m dubine.<\/p>\n
U istra\u017eivanju je kori\u0161tena posebna ronila\u010dka oprema za ronjenje u nadsvo\u0111enim prostorima (overhead environment<\/em>), odnosno u uvjetima u kojima nije mogu\u0107e izravno izroniti na povr\u0161inu. Radi dodatne sigurnosti, kori\u0161teni su odvojeni prvi i drugi stupanj regulatora prilago\u0111enih hladnim vodama. Za mjerenja dubine, azimuta kanala i temperature vode kori\u0161teno je ronila\u010dko ra\u010dunalo\u00a0Suunto EON Steel, koje sadr\u017ei digitalni kompas i mjernu traku. Za snimanje speleolo\u0161kog objekta kori\u0161tena su dva ure\u0111aja, Mnemo i ENC 2. Dobiveni podatci uspore\u0111eni su s podacima prikupljenim standardnim ru\u010dnim mjerenjem te je izra\u0111en detaljni topografski nacrt objekta.<\/p>\n Istra\u017eivanje je obuhvatilo novih 240 m potopljenog kanala. Duljina \u0161pilje Miljacka IV sada iznosi 500 m, dubina 32 m, a visinska razlika 34 m.<\/p>\n \u0160pilja Miljacka IV za sada nema, osim na ulazu, suhih fosilnih dijelova kanala, te je po svojoj hidrolo\u0161koj aktivnosti najaktivnija od svih \u0161pilja na podru\u010dju slapa Miljacka, \u0161to ukazuje na to da je po speleogenezi mo\u017eda \u201enajmla\u0111a\u201c \u0161pilja, posebice jer se nalazi na ni\u017eoj nadmorskoj visini od ostalih, bli\u017ee erozijskoj bazi. Me\u0111utim, u potopljenom dijelu kanala otkriveni su stalaktiti i saljevi koji govore da je u nekom razdoblju taj dio \u0161pilje bio suh. Postojanje speleotema koji se formiraju u vadoznim uvjetima ukazuje na to da je u nekom razdoblju taj dio speleolo\u0161kog objekta bio suh. Razlog tome mo\u017ee biti razli\u010dit: ili je paleotok kroz geolo\u0161ku pro\u0161lost mijenjao svoj smjer, ili u nekom razdoblju nije postojao, ili se mo\u017eda zbog tektonike (boranja i rasjedanja) mijenjao polo\u017eaj kanala u \u0161pilji Miljacka IV pa je u nekom trenutku bio iznad erozijske baze rijeke.<\/p>\n Iz suhog dijela \u0161pilje u potopljeni glavni kanal mo\u017ee se u\u0107i na dvama mjestima. Jedno je odmah kod\u00a0ulazne dvorane, a na drugom se ulazi iz jezera u njegovom sjeverozapadnom dijelu. Prostor kojim se glavnom kanalu pristupa iz jezera formirao se erozijsko-korozijskim procesima jakog toka vode. Ti su procesi otvorili nizak, \u0161irok prolaz izme\u0111u horizontalnih slojeva, te je trebalo nekoliko zarona da bi se na\u0161ao dobar put do glavnoga kanala. Glavni kanal u prvih 120 m, \u0161irok i niskog popre\u010dnog presjeka, dimenzija 4 x 1 m, generalno se pru\u017ea u smjeru SZ-JI. U njegovim bokovima vidljivi su erodirani slojevi manjih debljina. U dnu kanala nalaze se erodirani ostaci slojeva, u vidu o\u0161trih fragmenata stijena, ve\u0107ih i manjih dimenzija, dok u dijelu kanala u kojemu postoje spojevi sa sporednim kanalima ili kanalima koji su perspektivni za nastavak istra\u017eivanja postoje brojni vrtlo\u017eni lonci. Oblici popre\u010dnih presjeka nepravilnih su le\u0107astih oblika, koji ukazuju na to da su se erozijsko-korozijski procesi odvijali bo\u010dno (vjerojatno du\u017e slojnih ploha ili du\u017e vi\u0161e topivog sloja drugog tipa sedimentne stijene jer se du\u017e \u0161pilje izmjenjuju slojevi promina naslaga i vapnenca). Osim \u0161to se \u0161irio bo\u010dno, stvaranjem vi\u0161emetarskih pukotinskih ni\u0161a, u pojedinim dijelovima kanal se \u0161irio i u stropu du\u017e tektonskih pukotina, koje su vjerojatno indikator niza paralelnih rasjednih pukotina, sve kao rezultat intenzivnog boranja i rasjedanja na cijelom podru\u010dju (du\u017e kojih su se razvile i \u0161pilja Miljacka II i Sustav Miljacka I-V). Analiza smjera pru\u017eanja kanala i frekvencije pokazuje da je dominantni smjer pru\u017eanja kanala \u0161pilje Miljacka IV SZ-JI i da mu je azimut\u00a0 280\u00b0-290\u00b0\/100\u00b0-110\u00b0. Glavni kanal na nekoliko mjesta ima sporedne kanale, manjih dimenzija, dugih nekoliko metara, koji se ponovo spajaju na glavni. Nakon prvih 70 m kanal naglo mijenja smjer laktastim skretanjem u smjeru azimuta 10\u00b0-190\u00b0, a nakon 120 m ponovo se nakon laktastog skretanja pru\u017ea u smjeru SZ-JI. Speleogenezu toga dijela kanala mo\u017eemo povezati s nizom popre\u010dnih \u00a0pukotina u rasjednoj zoni, tako da je i ulazni dio \u0161pilje, koji je razveden, dio te popre\u010dne (relaksacijske) pukotine koja povezuje niz paralelnih rasjednih pukotina kao \u0161to su glavni kanal \u0161pilje Miljacka II i glavni kanal Sustava Miljacka I-V.<\/p>\n U prvih 20 m potopljenog glavnog kanala prilikom istra\u017eivanja uvijek je uo\u010davan adultni primjerak \u010dovje\u010dje ribice P. anguinus<\/em>. Ostala fauna uo\u010davana je du\u017e cijelog istra\u017eivanog dijela glavnog kanala s ve\u0107om brojno\u0161\u0107u primjeraka u dijelovima kanala s ja\u010dim protokom vode.\u00a0Na kraju istra\u017eenog dijela (kod 5. sifona, u predjelu nazvanom Bioportal) uo\u010dene su velike kolonije\u00a0bakterija. Tu je tok vode najja\u010di: mjernim ure\u0111ajem marke Seacraft izmjeren je protok vode od 70 m\/min. Temperatura vode iznosila je 12,9 \u00b0C. Osim kolonija bakterija, pri svakom zaronu uo\u010deni su pripadnici \u0161piljske faune, rakovi rodova Niphargus<\/em>, Monolistra<\/em> i Troglocaris<\/em>.<\/p>\n Istra\u017eivanje u glavnom kanalu stalo je na 18 m dubine jer zbog izrazito jakog protoka speleoronioci nisu mogli nastaviti s ronjenjem. Postoji perspektiva za nastavak istra\u017eivanja, koje u tom slu\u010daju treba provesti u uvjetima jo\u0161 ni\u017eeg vodostaja.<\/p>\n Daljnjim istra\u017eivanjima potrebno je topografski snimiti i sve sporedne kanale koji se spajaju na glavni kanal te pretpostavljeni spoj sifona i jezera s glavnim kanalom. Zanimljivo je da se 2019. godine, istra\u017eivanjem kod 4. sifona \u0161pilje Miljacka II, do\u0161lo do dijela u kojem je bio izuzetno jak tok vode koji je ponirao u ni\u017ee eta\u017ee. Mo\u017ee se pretpostaviti da je to isti tok koji se pojavljuje u \u0161pilji Miljacka IV, tako da bi se u nekim budu\u0107im istra\u017eivanjima tim kanalom mogle spojiti te dvije \u0161pilje.<\/p>\n Ukupna duljina istra\u017eenog dijela \u0161pilja na podru\u010dju slapa Miljacka (Miljacka II, Sustav Miljacka I-V, Miljacka III i Miljacka IV) sada iznosi 6 736 m.<\/p>\n Foto: Florian Launette, Ivan Milo\u0161<\/p>\n <\/p>\n [\/hr]<\/p>\n [en] <\/p> Dru\u0161tvo za istra\u017eivanje kr\u0161a Freatik i Zagreba\u010dki speleolo\u0161ki savez od 17. do 25. kolovoza 2022. godine proveli su speleoronila\u010dka istra\u017eivanja kanala u \u0161pilji Miljacka IV<\/p>\n","protected":false},"author":1,"featured_media":5918,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[44],"tags":[],"class_list":["post-9414","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research"],"_links":{"self":[{"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/posts\/9414","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/comments?post=9414"}],"version-history":[{"count":4,"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/posts\/9414\/revisions"}],"predecessor-version":[{"id":14043,"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/posts\/9414\/revisions\/14043"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/media\/5918"}],"wp:attachment":[{"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/media?parent=9414"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/categories?post=9414"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/npkrka.hr\/hr\/wp-json\/wp\/v2\/tags?post=9414"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![](\"https:\/\/npkrka.hr\/wp-content\/uploads\/Miljacka-IV_gl-kanal_5_2022.jpg\")
![](\"https:\/\/npkrka.hr\/wp-content\/uploads\/Miljacka-IV_gl-kanal_2022.jpg\")
![](\"https:\/\/npkrka.hr\/wp-content\/uploads\/Miljacka-IV_gl-kanal_4_2022.jpg\")
![](\"https:\/\/npkrka.hr\/wp-content\/uploads\/Miljacka-IV_gl-kanal_3_2022.jpg\")
![](\"https:\/\/npkrka.hr\/wp-content\/uploads\/Miljacka-IV_gl-kanal_2_2022.jpg\")
![](\"https:\/\/npkrka.hr\/wp-content\/uploads\/Miljacka-IV_gl-kanal_1_2022.jpg\")
<\/div>
\nResearch of the Miljacka IV cave (cave by the mill at the Miljacka slap waterfall)<\/strong>
\nThe Freatik society for karst exploration and the Zagreb Speleological Federation conducted speleodiving research of the channel in the Miljacka IV cave in the period from 17\u201325 August 2022<\/strong> The cave research in the area of the Miljacka slap waterfall first began in the 1970s. The last research conducted in the main channel gave great impetus for the further research of the cave, which stopped in the wide channel at a depth of 15 metres. During the research, special equipment was used for diving in overhead environments where it is not possible to surface. For additional safety, separate first and second level cold-water adapted regulators were used. To measure depth, canal azimuth and water temperature, the Suunto EON Steel dive computer containing a digital compass and measuring tape was used. To film the speleological structure, two devices were used, Mnemo and ENC 2. All data obtained were compared with data obtained using standard manual measurements, and a detailed topographic map of the structure was created. The research discovered a new 240 metres of submerged channels. The length of the Miljacka IV cave is now 500 m and depth 32 m, with an elevation difference of 34 m. With the exception of the entrance section, the Miljacka IV cave currently has no known dry fossil parts of the canal, and in terms of its hydrological activity is the most active of all the caves in the Miljacka slap area. This suggests that it may be the youngest in terms of its speleogenesis, particularly since it is situated at a lower elevation than the remaining caves, and is nearer the erosion basis. However, stalactites and curtains were discovered in submerged sections of the cave, clearly indicating that it was dry at some period. The presences of speleothems that form in dry conditions indicate that in some period, the entire structure was dry. There may be different reasons for this, either that the ancient watercourse changed direction over its geological history, or did not exist at a certain period, or the position of the canal in the Miljacka IV cave changed positions due to tectonic activity (folding and splitting) and at some point of time was above the erosion base of the river. From the dry part of the cave, it is possible to enter the submerged main channel in two places. One place is immediately behind the entrance hall, and the second is from the lake at its northwestern tip. The lake access to the canal is a space that was formed by erosion and corrosion processes of strong water flow. These processes opened a low and wide passage between the horizontal layers, and several dives were needed to find the right way to the main channel. The main channel generally extends in a northwest to southeast direction for the first 120 metres, when its dimensions are 4 x 1 metre, with a side and short cross-section. In the flanks of the channel, eroded layers of lesser thickness are visible. The bottom of the channel shows eroded remnants of layers seen as sharp rock fragments of larger and smaller size, where in the parts of the channel where there are connections to secondary channels or channels that are promising for future research, there are numerous potholes. The shapes of the cross-sections are irregular lens shapes indicating that the erosion and corrosion processes were from the side (likely along the layer surface or along a more soluble layer of a different type of sedimentary rock, as layers of promina deposits and limestone alternate throughout the cave). In addition to expanding the channel sideways by creating fissure niches several metres wide, in certain parts of the channel it expanded in the ceiling along the tectonic cracks, which are likely an indicator of series of parallel fault lines and all as the result of intensive folding and splitting along the entire area (in which the caves Miljacka II and the Miljacka I-V system were formed). An analysis of the direction of the channel and its frequency indicates that the dominant direction of the channel in the cave Miljacka IV is northwest to southeast, and the azimuth of the channel is between 280\u00b0-290\u00b0\/100\u00b0-110\u00b0. At several locations, the main channel has secondary channels that re-join back onto the main channel. They are of smaller dimensions and only a few metres long. After the first 70 metres, the channel suddenly changes direction sharply, in the direction 10\u00b0-190\u00b0, and after 120 metres the channel again suddenly changes directly sharply back to the direction NW-SE. The speleogenesis of this part of the channel can be connected with a series of transverse cracks in the fault zone, so that the entrance part of the cave that was indented is a part of these lateral (relaxation) cracks connect the series of parallel fault lines such as the main channel of the Miljacka II cave and the main channel of the Miljacka I-V system. In the first 20 metres of the submerged part of the main channel, an adult specimen of the olm, Proteus anguinus<\/em>, was always observed. Other fauna was observed in large numbers along the entire researched part of the main channel in the parts of the channel with high water flow.\u00a0At the end of the researched section (near the fifth siphon in the section called the Bioportal), large colonies of bacteria were observed. Here the water flow is strongest, and the Seacraft flow meter measured a flow of 70 m\/min. The water temperature was 12.9\u00b0C. In addition to the bacterial colonies, every dive recorded members of cave fauna, particularly crustaceans of the following genera: Niphargus<\/em>, Monolistra<\/em> and Troglocaris<\/em>. The research was stopped at a depth of 18 metres in the main channel, as divers could not continue due to the exceptionally strong flow. There are prospects for continuing this research, but in that case should be conducted in conditions of lower water levels. Further research is required to conduct topographic imaging of all the secondary channels that are connected to the main channel, and at the assumed connection of the siphon and lake on the main channel.\u00a0It is interesting that in 2019, research of the Miljacka II cave near the fourth siphon reached a part where there was an exceptionally strong flow of water that sank into lower levels. It can be assumed that this is the same flow that appears in the cave Miljacka IV, and future research of that channel could confirm the connections between these two caves. The total length of the explored cave in the area of Miljacka slap waterfall (Miljacka II, Miljacka I-V system, Miljacka III and Miljacka IV) has now come to 6736 metres. Photo: Florian Launette, Ivan Milo\u0161<\/p>\n<\/div>
\n[\/en]<\/p>\n","protected":false},"excerpt":{"rendered":"