Cueva Ojos de Cristal - Roraima 2005

Branislav Šmída*1 – Marek Audy*2 – Hernán Biord*3
  • 1 Slovak speleological society (SSS), Hodžova 11, 031 01 Liptovský Mikuláš, Slovakia
  • 2 ZO ČSS 6–17 Topas, Tyršova 332, 679 06 Jedovnice, Česko
  • 3 Grupo Espeleológico de la Sociedad Venezolana de Ciencias Naturales (SVCN), Calle Cumacho con Arichuna El Marqués, Caracas, Venezuela

During short tourist visit of the famous plateau Roraima (40 km2), at the borders of Venezuela, Brazil and Guayana, on 4th February 2002, Marek Audy and Zoltán Ágh, by the logical disappearing of water (but otherwise in fact accidentally) found the entrance to the subhorizontal inflow cave.
During the 1st expedition in the days 8th–15th January 2003, we explored here in the group of five: M. Audy, B. Šmída, E. Kapucian, M. Griflík and L. Vlček (members of SSS and ČSS, Slovak speleological society and Czech speleological society) not only the cave named as Cueva Ojos de Cristal (in Slovak or in Czech Kryštálové oči, in English Crystal eyes), in precise scaled map (scale 1:500) the length 2410 m, but also other new caves, with the total length of underground discoveries 3,7 km (Audy, Šmída, 2003; Šmída et al., 2003; Šmída, 2004; Vlček, 2004).
During the next expedition in the days from 20th to 28th February 2005, we continued in the speleological exploration of this area, already in the cooperation with the speleologists from SVCN (Grupo espeleológico de la Sociedad Venezolana de Ciencias Naturales).  (Šmída, 2005)

Cueva Ojos de Cristal

The system Cueva Ojos de Cristal is formed by the three evident main lines: Mischel, Cueva del Hotel Guácharos, and the first known Ojos de Cristal, which were connected into one complex with the length of 3164 m and with the elevation -48 m. Their main passages are 4–7 m wide and 2–3 m high in average. Locally however they reach the width 15–20 m, and maximum 10–12 m of height. The greatest known space is Sala con catarata (40 x 20–25 m). The inflow rivers flow through the branches Ojos and Mischel, at the circumstances when the passages are comfortable for the exploration (during relatively dry season January–March), with water flow 0,5–3 l/sec. (In the time of rain, the flow can increase to tens of l/sec.)

cave Roraima
Mapa Cueva Ojos de Cristal  y Cueva de los Pemones (2002-2005)

Cueva del Hotel Guácharos is the one with the higher position, originally surely the older branch of the hollow basin depression (100 x 180 m), where as if blind end of the valley is in fact the main entrance to the branch Ojos. The passages of the system are connected by some mutually parallel passages which are smaller in dimensions, they are separated from each other often only by narrow rocky barriers and connected to the labyrinth.

Their direction is much subhorizontal, as if little bit oblique, but otherwise almost without remarkable steps (the highest is about 4 m high, the other steps are about up to 0,5 m high) – the average cadence in the straightened cut is only about 2–3 %.

The cave tunnels go subparallel with the surface, not deep below the surface (20–30 m). The passages have mostly quite flat rocky floor, with micro-cuts, deepening, or somewhere with turbulent hollows (diameter up to 40 cm) and with swirl holes (so called "ojos de cristal"), which were engraved by quartz pebbles (originally crystals of pure quartz brought from the surface) – the name of the cave is by this phenomenon.

The passages are otherwise mostly without sediments, somewhere there are rocky bridges, or fallen pieces of ceiling (by the plate separation or the separation of ashlar shapes). In the fossil levels, or in the wider passages it is evident side "plastic" separation of the lengthy quartzite plates. The passages are generally significantly wider than high, commonly in the ratio of the width to the height 4:1
The cave has five entrances discovered till today, 3 of them are standard and 2 are in the form of remodeled vertical crevices (the deeper of them is about 100 m long and -18 m deep).


The cave was created by the secondary corrosion of the layers, which are the least resistant of the almost 98 % ortho-quartzite (mainly at interlayer discontinuities, and on the planes of hiatus), which is caused by the sophisticated enrichment of the water in organic materials, coming from the products of metabolism and from the decay of special endemic flora at the surface (for example also carnivorous plants). The repeating inflows of the water, during enormous rain seasons (the most of the year), apply significantly at the removal of the material from the block areas.

Cueva de los Pemones

The cave Cueva Ojos de Cristal likely has some genetic and hydrological connection with the next interesting cave in the close area named as Cueva de los Pemones (for the tribute of already mentioned indians – Pemons). These locations were not connected in the time of our research in February 2005, by physical personal passing through them.

One of the entrances to this second biggest system at Roraima, called as Pokemon 2, we had known already in 2003, it had been found by the duo B. Šmída and L. Vlček, on 14th January 2003 (Šmída et al., 2003). Other potential entrances to this genetic subsystem we also partially explored in 2003 (Cueva de Gilberto, Cueva Asfixiadora). The location we mapped precisely in the days from 20th to 28th February 2005, in the scale 1:500.

The passages of the main line Cueva de los Pemones, descending in the direction to the West, are 10 m wide in average, somewhere however even 15 or 20 m (or even more). Their height is also 2–3 m. The connection of the crossings and passages here also forms locally almost chaotic labyrinth of disorientation (mainly in the middle part of the cave). The main passage of the system is more compact, in the middle part (analogically as in Ojos de Cristal) with oval, also with ashlar shapes, and also with deeper lake pools, which must be passed around, by the several meters higher situated fossil parallel passages. (There are nice hollow pits in them.) There are also some collapsed little domes here. The biggest of the spaces is the lengthy passage-like hall, the dimensions are about 20 x 30 m and the height is 8–9 m. Two of the entrances are formed by about 100 m long collapsible crevices, about 25 m deep. Further similar, but little bit more shallow crevices (covered by high-mountain jungle) create the entrances to the South-ascending branch of the system.

    In the cave several smaller inflows connect together in the shape of delta, to one concentrated little river, with the minimal flow about 30–100 l/sec. (In the monsoon season, or at intensive rain, the flow can increase at least to several hundreds l/sec.) This river disappears in the cave in the floor with collapsed boulders, only some 80 meters from the vertical wall of the plateau. The most probably it feeds some strong spring at the heel of this wall, called by the indians Tuná Deutá, which is approximately 350–400 m lower (at the beginning of the access ramp to Roraima). The way to this remarkably vertical hydrological system unfortunately was not found yet.

    Cueva de los Pemones has the mapped length of 2070 m for now (200 m of less significant branches and spurs are drawn only for the orientation for now). The elevation of the cave is -73 m (Šmída, 2005).

    All the remarkable genetic system of the caves at Roraima has 13 known entrances for now (in the altitudes around 2600 m above the sea level): two of them are heading directly to 300–400 m high wall at the South edge of Roraima, about 30–50 m below the top plateau. (They were found by the exploration from inside and they are beautiful places, with impressive view from some kind of amphitheaters, with special flora.) The other 8 entrances are collapse crevices remodeled by the water (relatively direct, or only slightly curving), which are up to 25 m deep, from 1 to 3–5 m wide, and even more than 100 m long. Because they are by their characteristics different from the others and from the common "not cave creating" crevices at Roraima, we use for them not genetic term, so called pokemon (Šmída et al., 2003). These are oriented roughly in the directions WSW – ENE, and if they did not collapse to the underground totally there are higher longer halls created under them in the caves, with the falls of with the surface water in the form of dispersed drops falling down.

The length of the common genetic system of the caves Cueva Ojos de Cristal and Cueva de los Pemones, which could be later connected into one location, is 5,3 km now. At the close area of the plateau (roughly 500 x 1000 m) there is not impossible even to discover other less visible sub-branches and labyrinths, after the precise mapping of the branches maybe another kilometer of the length could be reached. Even the connection with the other close locations here is possible, for example with the cave Cueva de Gilberto (505 m long for now), Cueva Asfixiadora (125 m), Cueva Fragmento Marginal (78 m), or Cueva con Bloques de Piedra 2 (75 m). Beside these, we discovered bigger number of another caves at Roraima, 80–150 m long for now. Already in 2003 we explored some of the huge crevices, for example Grieta de Diablitos Volantes (-120 m), where some numerous colony of the blind birds live "guácharos" (Steatornis caripensis), or Cueva con Puente (-80 m).