The tepuis quarzites

Quartzite is better known with its technical name of quartz-arenite. It is essentially rock mostly made of quartz grains, the size of sand grains, cemented by silica. These rocks are very hard and resistant as a result of re-crystallization.
Quartz is the most widespread mineral on the earth’s surface but it is almost always interspersed with other minerals. Also it is very resistant to chemical weathering.
Alteration processes generally destroy other minerals leaving quartz and a few others intact. As a consequence, rocks subjected to erosion-sedimentation-lithification cycles are richer in quartz and tend to become quartzite.
Quartzite of the Gran Sabana formed almost 1.6 billion years ago in the huge continent that united Africa and South America. These sands are very ancient and were laid down by old rivers that flowed into a new land, devoid of any evolved forms of life. In these mountains, as a result of the separation of South America from Africa, rivers flowing down from the Andean Chain carved large canyons that isolated wide plateaus. It is right on these plateaus that waters started to penetrate into the rock digging the wonderful tepui caves, perhaps when dinosaurs were still roaming our planet.

The geography of Palawan

The island of Palawan has a narrow and elongated shape and is mostly mountainous for its entire length, with peaks of over 2000 m. The NE portion is bound on the W by a depression with NS direction. Just E of this discontinuity there is the important karstic area of Mount Saint Paul, 1028 m high, covering a surface of about 35 km2 and consisting of a limestone massive, dark gray, upper Oligocene - Lower Miocene. The formation, over 500 m high, is based on siltstone (fine-grained rocks into sand and clay), sandstone, marl and Oligocene lavas.

The outcrop of carbonate is formed by a long ridge oriented NNE-SSW, bound by the valley of the river Babuyan to E, and by the river Cabayugan to W. The structure is roughly due to a monoclonal dipping NW, bound by faults in NNE-SSW direction. This structural arrangement allows the system to receive contributions from karst sinkholes only from the side of Cabayugan, with the exception of the extreme northern portion, where even on the eastern side we have small marginal basins drained by sinkholes.

The whole area is affected by intense karst phenomena, typically tropical with superficial forms: towers, cones, cockpit, megakarren, etc... There are numerous explored caves, concentrated in two areas, north and south of the ridge, in addition to the general system of the Underground River, which currently has three entrances and over 32 km of development.


The past of Cuatro Cienegas History and archaeology
4CIn the pre-Hispanic period, the region of today’s state of Coahuila was part of the enormous cultural region known as Arid America, covering the area extending from Northern Mexico to the South-West United States. The region was divided into the following sub-areas: Central and South California, Great Basin, North-West Arizona, Apacheria, Lower California, Sonora and Sinaloa Coast, Southern Texas and Northern Mexico. This last sub-area belonged to the present state of Coahuila. Aztecs used to define Arid America as “The Land of Chichimec”, namely “the land of dogs people”, who were essentially nomads. Arid America had always been the most conservative cultural area of the whole American continent. Up until the period when local populations first came into contact with the Europeans, in these areas “archaic” lifestyles were endured that in other areas had been abandoned thousands of years before. For instance, in Meso America the so-called “Archaic period” lasted approximately until 1800 B.C, meaning that in the whole Arid America (except from a sort of island in the South West of the United States called Oasis America) farming was never performed, ceramics were never used, monumental buildings were never built and states were never created.
Arid American populations were organized in small groups of nomad hunters and pickers and their cyclical movements depended mainly on sources of available water. They survived in the desert environment basing their subsistence on desert plants such as pithayas, yuca roots, agaves, mezcal, palm-trees, roots and tubers, indian figs, on animals like foxes, hares, rabbits, rats, snakes, birds, insects and on natural products like honey.
4CAll groups were commanded by a head-man. Normally they occupied leading positions because of their personal status and they headed fights against rival groups. People used to live naked or wearing vegetal fibre or leather loincloths. They used to walk using sandals made of interweaved fibres. They had long hair, loose or braided, tied up with a coloured band on the forehead. They were very keen on creating tools, for instance they used to weave baskets, build wooden darts with flint tips which were thrown through propellers, stone grinders and pestles to grind the seeds they picked and working tools made of bone or horn.
Very little is known about their religious and spiritual practices. We know that they used peyote in order to have visions during ceremonies and while dancing through the music of drums, bells, pumpkins and snake rattles. They certainly possessed a well-articulated oral tradition. In fact,
we know that in some cases they used to wrap dead bodies in wicker mats or tie them up in funerary bundles. Considering the situation, it is not surprising if Aztec informers of Bernardino de Sahagún described “the Land of Chichimec” as follows:
“It is a land of misery, of sorrow, of suffering, exhaustion, of poverty and anguish. It is a land of dry rocks, of failure, a place of lament, of death, thirst, of starvation. It is a place of much hunger and death.”

Ethnic history of Cuatro Ciénegas
4CThe historical and ethnographic documentation of the colonial era, regarding the period between 1650 and 1750, proves that the region of Cuatro Ciénegas was populated in this century by various indigenous groups, known as the Coahuileños or Coahuilas, who were widespread in the whole region, north and north-east of the district of Parras-Laguna.
These groups, belonging to the hokano-coahuilteca language group, lived in the area extending from Mapimì to Monclova and Cuatro Ciénegas. According to historical sources, in the region of Cuatro Ciénegas, there lived among others, groups known by the following names: Cabezas, Salineros, Cíbolas, Baborizagames, Baborimamas, Corcobados, Ygoquibas, Yguitoros and Contotores.
4CIt is difficult to find out if names mentioned in various documents referred to ethnic groups, “gangs”, or even to simple family groups. These gangs were normally united by unstable and ephemeral alliances and wandered in the region performing raids against rival groups. In many cases gangs of Coahuileños were allied with (or, alternatively fought against) the Tobosos, a large group of vague affiliation populating the northern regions of Coahuila. It is likely that the habit of forming large alliances, often under the guidance of one single leader, was an innovation of the colonial era, due to the presence of a new common enemy: the Spanish invaders.
The fight against Spanish colonisers caused a rapid decline in native groups of the area and by the mid XVIII century they had almost completely vanished.
New indigenous groups benefited from this situation and moved into the lands of today’s state of Coahuila. Populations that moved in this region were the uto- Aztec, the Comanche and above all, from 1740-50, the Apache, an indigenous group belonging to the Athabaskan language group, whose origins were to be found in what is today Canada. This group occupied almost the whole region. However, they too very soon became a target of the new colonial world. In fact, nowadays native inhabitants of the region of Coahuila have almost entirely disappeared.

Archaeological research in Cuatro Ciénegas
4CAmong various regions of Arid America, the area of today’s state of Coahuila has been carefully studied on an archaeological level and is the source of most of the available data on the Arid American prehistory.
The Bolsón of Cuatro Ciénegas and the nearby canyons were explored between 1937 and 1947 by Walter W. Taylor during his Coahuila Project, which was partially funded by the United States National Museum of the Washington’s Smithsonian Institute. Taylor explored several caves of the region (ignoring the rare and poorly preserved open air sites), though results of researches were only partially published.
The archaeological heritage of the region of Cuatro Ciénegas is essentially characterised by cave sites and forms of cave art. In cavities all over the region traces of temporary human activities were discovered, fireplaces, several tools used for daily activities. Also various funerary sites were discovered, where dead bodies were wrapped in mats and covered with masses of stones. Cave art is particularly abundant and generally characterised by geometrical images of various colours, such as red, yellow and ochre. In some cases vertical and long anthropomorphic images can be observed, perhaps depictions of “spirits” of men during ecstatic experiences.
Research performed by the La Venta Association during the Cuatro Ciénegas Project do not have (at least for now) specific archaeological purposes, however throughout explorations of the area we have surprisingly found several archaeological elements, such as arrow heads, cave paintings and numerous funerary sites one of which was characterised by the presence of mats.
The main discovery has certainly been a refuge with a 30 m rock wall, covered with wonderful polychromic paintings. All archaeological findings have been documented with numerous photos and, clearly left in situ without altering their original conditions.

The archaeological sequence of Cuatro Ciénegas
The most ancient archaeological findings discovered in the state of Coahuila date back to the end of Pleistocene and consist of spearheads found in the Cueva Espantosa and in La Chuparrosa. However, at the beginning of the Holocene some of the most important cultural traditions of the area developed, related to the so-called “Desert Tradition”, represented mainly by the Bolsón of Cuatro Ciénegas. Torna al progetto

The Tepuis, the "house of the spirits"

The word tepui means "house of the gods" in the native tongue of the “Pemon”, the indigenous people who inhabit the Gran Sabana, in northern Amazon. This term indicates table-top mountains located in the north-east side of the Amazon forest.

Tepuis are unique mountains: square-shaped, wide summit surface limited by high vertical walls. Due to strong erosion some tepuis have the shape of huge isolated towers, up to 1000 m high. The landscape can resemble the Dolomites, though the dark colour of rocks and the thick vegetation surrounding them are absolute distinctive features.
Amongst the most outstanding tepuis the Auyan Tepui is one of the most famous one, on the border of Venezuela, Brazil and Guyana, due to the fact that here is the source of Angel Falls (Salto Angel), the world's highest waterfall, almost 1000 m high. Its surface exceeds 700 km2 and was our first target of explorations in 1993 and 1996.
Tepuis are wonderful mountains, often cloaked by clouds and mist. Rains are very frequent and waterfalls draw up an extraordinary and unique landscape. These mountains are the setting of Arthur Conan Doyle’s famous novel “The Lost World”. The author imagined a world that had not changed for 10 million years, where dinosaurs and Mesozoic plants survived. There seem to be no dinosaurs, but for sure the flora is one of the most incredible of our planet. Tepuis are the home of a unique array of endemic plant and animal species, some of which have not yet been catalogued. Each Tepui has distinctive features and is isolated from others by steep rock walls.

The Puerto Princesa Underground River (PPUR)

The cave consists of a main axis, developing in the direction NNW-SSE, about 7 km long and formed by a large gallery crossed by the river. The main gallery has several branches, and some modest tributaries, especially from the left. The main tributary is the Australian 's Inlet, just downstream of the Rockpile, coming from a depressed area located just south of the Barrio of Sabang. Another small left tributary is located not far from the daylight. On the right side, the only noteworthy tributary is located about 1 km upstream from the Rockpile, and comes from a short branch closed by a siphon.

Parallel galleries at altitudes close to sea level, develop especially on the left side of the main branch, in its middle and lower part (Cin Gallery). Part of these galleries is reactivated during floods, as evidenced by the presence of significant alluvial deposits. At the bottom of the underground river develop other small parallel galleries, semi-flooded, giving rise to a sort of grid of twisted channels, typical of estuarine intertidal zones (areas located between high and low tide).

One of these lateral branches, which starts on the right side about 150 m upstream of the entrance of the valley, spreads a few meters above sea level up to an impressive stalagmite flow beyond which the gallery continues gaining considerable size and gorge morphology. In fact, we have entered a sort of parallel way of the river, whose existence was suspected from some time, fed by infiltration water collected from karstic massif and not from sinkholes, so active only during the wet season.

The gallery (150 years gallery) in some places has widths up to 30 m and heights of 40-50 m and extends for approximately 4 km towards SW, then parallel to the main river, but a few dozen of meters higher. The morphology is that of a large underground canyon with erosion terraces on the walls and alluvial deposits. For long stretches the walls are covered with spectacular crystal coralloid and eccentric concretions. The gallery ends with a great landslide (Magellan Chamber), close to the great halls that are above the main river. Below this gallery we find some branches with clearly epiphreatic morphologies, probably formed by the periodic ascent of the piezometric surface.

In the southern portion of the underground karst system there are, however, some large upper branches (Halohalo Gallery), on the right side of the current active route, which represent segments, now divided by slumping or fills, of an ancient route of the underground river with tunnels that have dimensions generally larger than those of the current collector. Where is preserved the original shape of the duct, the portion of the floor is about 50-60 m upper the sea level. Many sectors have been subject to slumping, that have expanded the size, creating large rooms such as the Italian's Chamber, which has a length of 300 m, a maximum width of 140 m and an estimated height of 80 m, with a volume of approximately 2.5 million cubic meters.


underground rivers

As usually happens in tropical karst areas, many caves are the underground domain of rivers that, throughout their course meet calcareous ridges, and at the foot of large blind valleys big portals open up and rivers suddenly disappear to re-emerge somewhere else.

In the region south of Kalaw there are many caves of this kind but we had the opportunity of exploring them only partially during the 2005 expedition. One of them is formed by a large tunnel connecting two adjacent valleys. Evident traces of transit found in the cave prove that it was used as a route of communication in the past. We explored another cave for a kilometre; it was rich in water fauna, such as giant prawns and blind fish.
The largest ponor we discovered is located at a three hour walk from Pinh-ton, a remote mountain village, 80 km south of Kalaw. The river plunges in a 50 m waterfall, that was impossible to descend due to the huge amount of water, and continues its flow in a vast canyon that carries on in the dark. The river re-emerges from the springs of Namun, around 7km away.

It is a wonderful place that can be reached in 3 hours by boat sailing up the river. Here, at the foot of a limestone cliff, a small cave appears as an underground lake in which we hear the sound of a waterfall. What is between ponors and natural springs is still unknown; for sure it is a vast underground system of water tunnels yet to be explored.

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