Peștera Hodobana/ din Pârâul Hodobanei, descriere, hartă 22.142 metri lungime, în Munții Bihor

articolul continuă de la

Liviu Valenas 

Peşterile din România

Hodobana Cave, a unique maze in Europe 

Abstract

The Bihor Mountains host the cave from Hodobana Creek (22,142 m length). Hodobana Cave is one of the largest cave of Romania. It is the most challenging maze in limestone from Europe! Cavern occurred in compact limestone of Jurassic age and resulted from the water-intake of Hodobana Creek on an aerial length of 812m. The decrease in the groundwater level created a cave built on 8-24 levels. These brief data characterizes the cave as the only one in the top of Europe.

History of explorations

Speleological Club “Z” started intensive and methodical researches in the Gârdişoara-Gârda Seacă region since the 1973 year. In April 1979, Florin Păroiu and Nicolae Sasu looked for access to the underground watercourse between final sump of Coiba Mare Cave and Tăuz Resurgence. By chance, they found a tiny hole in one slope of Hodobana Creek, a tributary of Sohodol Valley. Entrance in the cave had only 1m/0.8m and did not encourage the cavers, but a stream of air gave hope. After 13m of a severe, upward crawl, they reached a small hall plenty of boulders. The air current blew weakly between floor stones. An easy removing of stones and a 2.5 m drop created access through rock boulders. They entered a 40m-long horizontal gallery (Subway Gallery) and then into a larger room- Florin Păroiu Hall. A confusing landscape, small drops, and squeezing paths led them to the edge of a large-size shaft- the Speranţei (Hope) Shaft, 28m-deep where they stopped. Speleological Club “Z” organized a new campaign in August 1979. Nicolae Sasu, Florin Păroiu, Eva Györfi and Nicolae Paul descended the Speranţei Shaft. They crossed one small phreatic gallery and several tiny drops and reached final sump at 150m in depth (later mapped at -119m). These first explorers of network appreciated cavity length at only 2km.

On September 1979 Liviu Vălenaş decided to explore and survey the giant maze and took two revolutionary decisions using single-rope techniques and teams of two or three cavers. Along with Eva Györfi, he mapped the access up to final sump at 119 m depth. On October 1979, Liviu Vălenaş and Nicolae Sasu did a new campaign. After lowered the 28-meter deep shaft in Gothic Hall, they walked upstream on the same course mapped downward to the final sump. Climbed free a 4 m high waterfall, passed through a meandered route including Dante Hall and stopped above Mammoth Hall on the edge of a 20 m drop. An inclined plane avoided the drop and allowed free descend. Next four campaigns of mapping proved Hodobana Cave has developed in the upstream watercourse on many floors. After the first 3-4 levels mapped, it discovered other floors. Twenty-four floors in total including the intermediate levels. Exploration came to a deadlock at the end of October 1979. Lack of people. The solution was to join forces with other caving clubs or singles. Cavers from Romania and abroad came and helped Liviu Vălenaş to map the cavern. These caving clubs are “Emil Racoviţă” Bucharest, “Speodava” Ştei, “Flacăra” Iaşi, “Casa de piatră” Turda, “Hades” Ploieşti and “Cristal” Timişoara from Romania and “ZHKTJ” Katowice from Poland. In December 1979, Liviu Vălenaş, Horia Mitrofan, Nicolae Stoica-Negulescu and Rodica Stoica-Negulescu explored Mammoth Hall and forced a squeeze to several fossil levels. Then, they discovered a 20-meter-wide shaft and descended it to a big underground river. A few days later, Liviu Vălenaş, Constantin Gagea and two Polish cavers descended again to the big river hall. They explored downward watercourse to an impenetrable sump. Then, explored a 1,020m-long, meandered, and tight gallery on upstream course to an ending hall. In Terminus Hall (Sala terminală) is a final 30m high waterfall, and that team did not climb it. The ground surface is near it. In February 1980, Liviu Vălenaş and Dan Nanu explored the Eastern Side. It is a fossil network (Slave Canyon, Wind Gallery, Dan Nanu Gallery, and so on), a distinct part of the cave. Here are the most stunning speleothems and the largest galleries in diameter. During the 1980 year, it mapped the superior floors of the Hodobana Cave. A fascinating work that showed an incredible increment of multi-level fossil galleries. They are 6 to 8 main floors and three times more secondary floors. In October 1980, Hodobana Cave had 15,752m length. In only one year! A national top-record of mapping and exploring for a cave in Romania. During 1981, Liviu Vălenaş and Caius Tenţ discovered the continuance of the Great Tributary. They mapped near 2 km of a new stream and its upper floors. It was the last important discovery in HodobanaCave. Meantime, it mapped other sectors limited by fossil levels. In 1981, the cave recorded 22,042m development. By discovering of a small upper floor, Liviu Vălenaş ET co. in 1987, the cave length passed to a new length figure unchanged until today, 22.142m. Under the patronage of Speleological Club Z, outlines more accomplishments. In the year 1983, Liviu Vălenaş, Caving Club “Speodava” Ştei (Petru Brijan and Ovidiu Cuc), and Cristian Lascu organized scuba diving into the final sump at -119 m. Cristian Lascu dived and explored the sump on 5 m distance and 2 m in deep. The sump was tight, the water muddy and without visibility. The safety made him renounce. There is no hope of passing through this point to the underground river between Coiba Mare Cave and Tăuz Resurgence.

A Polish team together with Nicolae Sasu climbed a 60m high slide from the Coralloids Gallery. They used bolted anchors and reached a bottom bag near to the surface. It is the greatest cavity positive elevation touched by cavers. Hence, Hodobana Cave has a total elevation unevenness of 181 m (-121 m; + 60 m).

Later, Petru Brijantried to climb the 30m high waterfall from the Terminus Hallusing a climbing platform and bolts. He and Liviu Vălenaştransported in harsh conditions, a massive steel platform! Petru Brijan abandoned after climbed 10m. A few months later, two Polish cavers used same platform and bolts but abandoned after 20 m.

In 1983, Liviu Vălenaşdrew the large map of Hodobana Cave, at a scale of 1:200. In February 1984, Museum of Oradea City held a public meeting showing the map. After 1987, no one ever reached the final point of the cave. European cavers agreed that orientation inside the cave is impossible. Hodobana Cave became a legend and a dream. 

Description

In the middle of Bihor Mountains, Hodobana Cave opens into Hodobana Creek right slope. Hodobana Creek is a tributary of Sohodol Valley in the river basin of the Gârda Seacă Valley. The first two valleys are karst-valleys, so-called “sohodol” - with no surface course and gorge up to 80 m high. The cave entrance has an elevation of 20m above Hodobana Creek, and an altitude of 980m above sea level. Cave developed in East-Southwest direction. The water lost in Hodobana Creek, Hoanca FileştilorSwallet and neighbor sinks, created the three underground courses- up to 1,010 m long each.

The entrance into the underground network is small (1 m/ 0.80 m). After a 13 m-long-low ascending gallery, enters a small chamber of 5m/2m/1.5m full of boulders. Through a 2.5 m-deep shaft, reaches a small maze, followed by a 40 m-long and 1m-high straight horizontal gallery, the Subway Gallery. This gallery comes into a larger room, Florin Păroiu Hall and the continuance is confusing. It crawls along a new low passage, Hedgehogs Gallery, which opens in a broader space. In the left, climbs 50 m-high on Coralloids Gallery, the highest point of the network (+ 60m). In the front-right, a slide descends to Speranţei Shaft, 28 m-deep. Little to the right, it reaches the upper part of Slave Canyon, which allows shorting of the 28m-deep shaft through an extreme free descending. To the right, Slave Canyon, tight and challenging, reach into the Eastern Side. It is the fossil part of HodobanaCave measuring 1.5 km of large galleries including Amphitheater Hall, Wind Gallery and Echo Gallery. The last one is a descending water slide with a unique acoustic in Romania. Eastern Side has the most stunning speleothems in Hodobana Cave. Noteworthy a chimney reaches only a few meters of surface, the air stream and fir-tree roots prove this. From bottom of P28, it descends to Gothic Hall. There on the right hand, a small-sized phreatic gallery hosts a stream that flows over drops up to 6m to a muddy sump. It is the deepest point of the network, -119 m (by diving, C. Lascu, -121 m). The main continuation of the network starts with a free and acrobatic climbing over a 4m high waterfall upward Gothic Hall. Hodobana Cave shows its real face, 24 levels developed on 6-8 core floors oriented on the west-southwest. It follows Dante Hall. A medium-sized rocky chamber. Through a negative angled phreatic tube with clay reaches the largest cavity of the network, the Mammoth Hall, full of boulders, 57 m long, 20 m wide and 42 m high. The top cave floor passes above this cavity and through a window can descend into the middle of the hall on a 40m rope. It is the biggest cave vertical. A small stream disappears from this chamber into an impenetrable sump. The cave continues through the hall western side. Passes through a squeezing passage and then climbs a step on 15m high to a superior gallery with concretions. Walking on superior levels, it passes through “Storm”- an ascendant squeezing earth-floor passage where met the mightiest air blow and reaches the top of Grand River Hall, where from can descend a drop in two-steps of 20m each direct in the hall. Downward, Grand River ends in a rocky and impenetrable sump. The stream flow rate is 10l/s the biggest by far. It continues walking free on a dangerous level of erosion above the Grand River Hall. The Grand River flows along a meandered low level. Gallery has several cut meanders, 30 cm-40 cm width, and 1,020 m length. Above it, Hodobana Cave maintains same face, an extreme multi-flooring, over ten fossil levels, including secondary ones too. After 200m, a small 3m high waterfall from the right side, announces the Grand Tributary. The new gallery is 250 m long and multi-floored (over 2 km long).

Grand River continues its upward way and before its end is a junction, on the right side, with a 100 m long and low gallery. From here, the watercourse follows a narrow gallery and ends in a 30m high room watered by a waterfall coming from the ceiling. It is Terminus Hall at 2,020m of the cave entrance. Here, climbed 20m, but the ceiling has few meters to surface and cannot add a significant length. After Paul Damm (Damm, P., Moréh, K., 2011), the final waterfall originates from nearby Hoanca Fileştilor Swallet (ponor). Hodobana Cave has a length of 22,142 m and development on vertical of 181 m (-121 m; +60 m). Cavern developed on an aerial length (extension) of 812m, and its branching coefficient is 27.3! It is the top one in Europe for caves in limestone. Is interesting that Liman Cave in Dobrogea, a maze in limestone 90% dug by humans, have a branching coefficient of 11.0. (a most real situation of branching coefficient is at https://sites.google.com/site/romanianatura40/home/carpatii-rasariteni/rodnei/groata-zanelor-rodnei-record-national-de-ramificare)

Geology and tectonic

Hodobana Cave develops in fractured-limestone of Jurassic age (Lower Neocomian and Inferior Aptian) and in a frail tectonic of Saxon pattern. It is obvious in the cave's map that galleries develop along two-main-fractures: NE-SW and NW-SE, somewhat in a “chessboard” pattern. At the surface can recognize this tectonic pattern in the main faults and joints of the Gârdişoara-Gârda region.

Active tectonics

The cave from Hodobana Creek is a helpful field for the study of active tectonic in endokarst. The active tectonic results from many factors. To examine the primary and post-primary arrange, we must recall the big development of the network (over 22 km), the highest number of floors disposed on 181 m elevation unevenness and that galleries built up in nude rock. By forcing our knowledge to the essence, we can define many forms, separated by morphology and the forming mechanism. Below are these cases.

1. Galleries fractured on vertical.

Are “micro-faults” (Fig. 1), forming a tract of 5-10 cm, visible along the top of various galleries (cannot see it on floors because of rubble or alluvial components). Morphology of ceilings shows separation occurred afterward excavation and shaping of galleries (on both sides of the micro-fault line are same corrosion forms and speleothems).

2. Galleries fractured on horizontal (strike-slip faults).

This case (Fig. 2) is further widespread in Hodobana Cave than the last one. It manifests as a fracture that moved on horizontal in opposite directions the gallery often at a 60-80° angle, having a bigger displacement (10-30 cm) than the vertical faults case. The fault line spread from one wall to another and is a large crack unshaped later by corrosion and decompressed to 1-2 cm (often with friction mirrors).

3. Rock benches or terraces fractured on vertical.

They refer to vertical oscillations of the gallery wall (Fig. 3), afterward divided on vertical by “micro-faults”. The most prominent pattern is a rock-bench suspended at 18 meters above the Great River bed having the front taller with 5 cm than the inner part near the wall. This is not a local or gravitational event, but active tectonics.

4. Segmented pillars or corrosion blades.

Micro-faults have sectioned on vertical these morphological forms (Fig. 4a and 4b) created in a phreatic regime, while the “micro-strike-slip faults” shaped them on horizontal.

5. Blades of rock distended.

They (Fig. 5) are frequent in the cave of Hodobana Creek and are an odd form. It is a thin limestone blade (5-10 cm wide), lowered by gravity through friction between reactivated strikes between two “micro-faults”. Distended blades displaced on horizontal are rare.

6. Friction mirrors.

Friction mirrors appeared either from the reactivation of the original mirrors (and then polished) or are later mirrors produced by moving of “micro-strike-slip faults”. It is a normal form in Hodobana Cave.

7. The crush of ceilings.

This case has nothing to do with active tectonics, but within Hodobana Cave is a specific feature generated by “micro-defects” and “micro-strike defects” that have destroyed the balance of limestone beds. The irreparable effect is a huge collapse of the rocks that lead to the closure of the galleries and the chambers (Fig. 6).

The forms described above exists in reality and nothing can contest it. A further detailed study can develop the forms described. We must notice the exact similarity with forms from the Occidental Tatra Mountains (Poland), Fig. 7 and Fig. 8, or with the new-discovered forms in Pădurea Craiului Mountains, in Igriţa Cave (Vălenaş, 1980-1981) and Hodoaba Cave (Vălenaş and Jurkiewicz, 1980-1981), Fig. 9 and Fig. 10.

Morphology and genesis

Hodobana Cave resulted from a progressive underground Hodobana river loss. The cave developed on the right slope, parallel to the actual valley, and is near the surface. Its genesis relates to Hodobana river bed water infiltration and to meteoric water loss in the large sinkholes and Hoanca Fileştilor swallow-hole from valley's origin watershed. (Damm, P., Moréh, K., 2011). The cave formed into a bati-phreatic regime, being immersed. The upper fossil-floor exhibits many elliptical sections and a great break of limestone because of an intense tectonic. As a curiosity, this bati-phreatic gallery has none speleothems. Cave network had one kilometer in extension at the beginning. Eastern Side of Hodobana Cave is a Paleo-watercourse to a Paleo-resurgence in SohodolValley. Between the Hall of Collapsed Stones and surface is a distance of a hundred or 150 meters but the Paleo-resurgence did not find yet. In geological time, total loss of Gârdişoara river moved downstream in Tăuz Resurgence (850 m altitude). The relevant underground course has moved beneath the Sohodol Valley and had an enormous impact on Hodobana Cave. The Paleo-watercourse of 2,000 m long, has separated into three major sectors and aspirated by the Tăuz Resurgence. Cavity passed to a vadous regime because Tăuz Resurgence is at 140 m elevation below the Hodobana Paleo-resurgence from the Sohodol Valley. Effect of the vadous regime is a remarkable multi-floored network, unique in Europe. Many of the floors are of the same gallery with narrow erosion levels filled with alluviums, collapses and speleothems.

Hydrogeology

It did not do coloring of the watercourse in Hodobana Cave. But, without doubt, the three main underground watercourses drain through Tăuz Resurgence because the cave and the resurgence are in the same geologic unit, Tăuz Hill. Tăuz Resurgence has a flow between 0.530 and 10 cubical meters per second at floods. Beyond small final sumps of the three main watercourses, flow is changing to a phreatic regime until joining to the big groundwater stream between Coiba MicăCave and Tăuz Resurgence. A coloring or marking of water could prove it. For illustration, between the final sump from -119 m and Tăuz Resurgence (850 m altitude) are only eleven meters elevation unevenness on an aerial distance of 800 meters and it sustains our hypothesis for a phreatic drainage regime. In 2014, two Finnish cave-divers, Sami Paakkarinen and Patrik Gronquist succeeded to dive at 83 m depth in the TăuzResurgence sump 2 and found a vadose stream, climbed a waterfall of 4 m and explored on several hundreds of meters until the sump 4. We do not know whether Finnish speleologists met the tributary coming from Hodobana Cave.

Climate

The temperature of the air is 5 degrees Celsius. The cave is high aerated, with many vented spaces. Humidity: over 90%.

Mineralogy

Hodobana Cave is one of the richest caves in stalagmites and calcite crystals. They develop in the upper fossil-floors and in Eastern Side. Besides calcite, no further minerals identified. Galleries with watercourses and large halls affected by stones collapsing have not significant formations.

Bio-speleology

It has conducted so far no studies of bio-speleology. Identified only isolated bats. They are crawling through the squeezing passages, being an interesting phenomenon observed by Liviu Vălenaş in 2016 in Thailand, in Tham Nam Lot Cave.

Conclusions

Hodobana Cave is a unique cavern in Europe because of multi-flooring (up to 24 floors), that created a horrible maze, the cave has an extreme branching for a cavity formed in limestone: 27.3. The genesis of the network has derived from infiltration into the alluvial bed of the Hodobana Creek. A later descent of the groundwater table and the drainage through a later outbreak- Tăuz resurgence, led to this remarkable multi-flooring. The cave- developed in faulted Jurassic massive limestone and the moving of Hodobana Creek through erosion to the South, produced a strong stress relief in the limestone pack, and a notable dynamic tectonic (mini-faults, mini-ditches, massive rock collapses, etc.). Hodobana Cave is singular in Romania. From a hydrogeological point of view, the cave is draining through Tăuz Resurgence, and continues with one of the most impressive underground water streams from Romania, partly vadose, with deep sumps (a -83 m in Tăuz Resurgence and -92.5 m in Coiba Mare Cave, the last continues below this figure), and partial explored (2016) because of significant technical issues.

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