081 Cueva de Carcavuezo
La Secada 30T 452883 4798000 Alt. 150m (T.Length 43437m end of summer 2002) Depth 28m
Sink GPSed at approx 30T 452618 4797999

Updated 13 February 1998; 19th February , 18th April 1999, 12th December 1999; 16th September 2000; 21st January, 1st April, 29th April, 7th October, 26th October 2001; 25th October , 11th November 2002; 15th October 2003; 8th October 2005  

Part of the Sistema de Cuatro Valles.

The above altitude is for the cave entrance. The altitude of the sink is about 145m. A draughting hole above the sink was discovered in 1990 and may provide an easy entrance to the Western Series.

Cueva de Carcavuezo is the modern main feeder to the Four Valleys System ( line survey) and is the major exit for water out of the Matienzo depression. The water has been dye tested to the Los Boyones resurgence in Secadura. (A small amount of water sinks in the Orillón complex ( site 023), and is presumed to flow south towards Ogarrio).

A direct and relatively straightforward route exists into Cueva Llueva (114); the route to Cueva Hoyuca (107) is through a collapsing boulder choke and should not be attempted. The sink in high flood lies under 5m of water; the earlier, lower sections of the 1986 Extensions are likely to sump up with little rain.

The río Matienzo (also called the río Clarín) sinks into a mass of boulders and logs. A deep, excavated and normally dry stream bed beyond this leads to an area of boulders and flood debris. A draughting rift on the northern side of the flood sink is the entry point - the first trip after heavy rain may  need to excavate the entrance of its logs and other flood detritus.

Route finding in the boulder strewn, descending rifts and large phreatic tubes is facilitated by the draught. At a low chamber, a stoop ahead leads to a chossy climb up into an area which could bypass the present, flood-prone route; to the left an arrow marks the usual squeeze down into a descending, bouldery rift and a short drop to a block at the top of the river passage. A straight climb down or a less exposed drop between the bouldery walls leads down to the river. More boulder chokes have to be passed before the sump pool is reached within 200 metres. This has been dived to a boulder choke and holes directly above the sump have been maypoled - there is a possible draughting continuation here.

Much poking about in the roof of the choke has also occurred.

Two ways into the major east and west extensions exist, the 1986, low level route contains rocking boulders but may need to be followed to hang a ladder down the climb for the other route.

Most cavers should follow the stream down until a ladder is noticed hanging from the roof. A climb up leads directly into the 1986 (Easterly) and 1988 (Westerly) Extensions.

The entry point to the low level route to the 1986 Extensions lies on the right of the stream and is a 3m climb down an awkward fissure to a pebbly crawl into a wide bedding and, after 20m, a rocky squeeze. A small climb to the right then drops down a rift to a small, gravel-floored chamber with a pool. A climb up to the left followed by an uphill slide through a body-sized right angle leads to a muddy climb over and between boulders and two slippery parallel drops of 4m. Either of these lands in a small, muddy passage and a straddle climb down to water. A short crawl over mud and gravel leads to the base of 30m of clean-washed rift passage. A bridging climb of 6m pops up into large passage, the start of the Afternoon Stroll in the Easterly Extensions).

After 130m of pleasant stroll in a phreatically enlarged rift a breakdown area, the Light Frigit, is met where other passages converge from the north. One, the Third Fanny heads back towards the entrance but ends at a series of choked phreatic rifts to the north and a very low bedding to the west. The Fourth Fanny heads north and back towards the Third Fanny ending in a boulder choke, not fully explored and not surveyed.

The main line continues east enlarging to 4m wide and high until a similarly-sized passage joins it from the south. Ripple marks in the sand appear to indicate water flow from the south and west heading eastwards.

The Southern Inlet continues in similar style for 100m where at a junction to the right, a narrow rift leads over a traverse to calcited boulders. At the bottom of the traverse a phreatic maze leads back to the junction. The southern end of the Southern Inlet degenerates into low crawls under the walls.

The main route continues east down a large passage with fine floors of eroded and scalloped mud. After 100m, breakdown is encountered and a very large boulder almost blocks the passage. Beyond is Red Column Chamber, a large breakdown chamber with a few small stal and a 3m long red formation in the NE corner.

Duck Passage is the route which heads east out of Red Column Chamber and is a smaller, 3m square passage. It is formed in a bed of nodular limestone which has broken down extensively to small, muddy rubble in places. After an initial rise, the passage gradually slopes downwards, becoming muddy and passing the eroded rock, The Duck, after 90m. The next 120m appear to be fault guided with a hading wall on its south side. Numerous blind phreatic rifts are present in the wall and the roof. A few small white formations brighten the drab, mud-covered passage. Passage size varies from 6m wide and 4m high but is more commonly 3m square and, progressing east, becomes more obviously phreatic with rifts and short, mud-blocked side tubes, the passage now being lower than the friable bed of nodular limestone. Eventually a muddy maze of walking, stooping and body- sized phreatic passages is entered (at least 110m of which is unsurveyed), all soon forming parts of two routes through a truncated section of large passage blocked at both ends by sediment. After an initially large segment 5m wide by 4m high, floored by dried mud the roof has collapsed from the over-lying nodular limestone beds, mainly choking the passage at Gypsum Chambers. Crawling over and under gypsum-strewn muddy boulders leads via an squeeze to an unpleasantly small, muddy tube with pools in the floor and ending at an 18cm wide connection with the Pease Pudding Passage of Cueva Llueva (114).

In 1999, opposite Straw Passage, over 500m was surveyed in Parallel Sausages. At Andy Quin's Foot, 100m of passage (Ramon Bolado) was surveyed which heads back towards the upstream sump passages in Cueva Llueva.

An impressive canyon passage leads from Red Column Chamber over large fallen blocks to a rock bridge with a metre deep pool beneath. The canyon bottom is now mud and splits to a lower passage The Rectum and a climb past a large rock pillar into Argument Passage. Above the pillar, a 4m climb give access to a 3m x 2m passage trending NE with branches and boulder blockages. One route leads back to Chase the Dragon after about 100m.

Argument Passage continues 10 - 12m high and 10m wide to end after 70m at a mud-covered boulder slope. The top of the slope has very nice red stalagmite cones up to 1m high and chokes in large boulders. Following the southern wall, a draught encourages squeezing between stalagmited boulders. This has been pushed for 20m to where the draught disappears between muddy boulders.

The Rectum is the start of Chase the Dragon and takes the strongest draught between Cueva Llueva and Carcavuezo. It is a muddy passage up to 4m wide but mainly low stooping under an arched roof. Side branches have not been surveyed or pushed. After 150m the passage narrows with potholes in the floor and soft, friable shaley rock. After a few short oxbows (not shown on the survey) the passage forks.

Keep Right For Smack is the way through to Llueva and carries the strongest draught. The route is through shallow pools and over slippery calcite mud and after about 80m pops up in the floor of Cueva Llueva, about 100m west of the Rhinoceros. ( Continuation Passage is straight across from the entry point and is a climb down in boulders. The passage continues as a small series of hands-and-knees, mazey tunnels which run around the north side of the Smack Choke but ends too tight).

The Maze is the alternative route to The Rectum. It contains at least 100m of unsurveyed junctions and oxbows. Its limits to the west and south are not known. By following the draught a route is found through to the Abattoir, a red mineral-smeared area where a climb down drops into a river running in amongst boulders. By following the river to the west the Sewers of Doom are reached above the river and eventually the Candy Shop in Cueva Llueva. The Candy Shop has deep red gour pools on the boulder pile.

Most of above by Terry Whitaker. Passage development arguments in file.

The Western Series needs writing up. The ladder up broke in the summer 2003 and is now next to a replacement as the krab on the old one has broken.
Barn Passage comes very close to the building which Alberto is doing up. He has told Pete that there used to be a natural drainage for the cow-shit inside the shed. So it may be worthwhile re-investigating this area of the cave - or his new house. There appears to an an remnant arch behind the house that is full of debris.
At Easter 2001, the sump in Ovlov Passage was dived through into a 25m rift chamber with a narrow squeeze. This was pushed in the summer with 30m of under water passage that was still going. The sump is further into the hill than the Volvo passages and is parallel to them. In October 2002, the sump became too wide over "silt dunes". It was noted that the passage is heading south towards Volvo. The dig at the entrance to the sump was also examined. It appears to be a good site as the passage is not heading straight for Volvo, rather heading west.
In the very dry summer of 2003 "the water level had gone down and there no flow from the sump so would be a good place to dam and bail; estimated time of bailing 3 hours with a bucket leaving a 'dry' sump. The first sump would take about half an hour to bail but this just leads to a rift with a sandbank and the other sump would have to be bailed. It's approximately 4-5ft deep in current conditions".

An extension at the end of the Draintester Passage in the Western series - Purgatory - was first entered in 1991(?) for about "300m". The small passage was surveyed for 248m in 1997 and is still going for at least 60m is similar passage. The lowel altitude route passes below the middle arm of Trident Passages in Cueva Hoyuca (107).

L. Mills found a Lithobius in 1986.

Matienzo and its caves are mentioned in the Diccionario Geográfico-Estadístico-Historico de España Tomo XI, a geographical dictionary published in 1848 (Madoz Pascual, 1848). Comellantes is mentioned as the resurgence into the depression with water disappearing in La Secada and appearing in Secadura after ½ league underground. Bad flooding and poor roads are mentioned. The Cavernas y Simas de España (Puig et al, 1896) mentions various Cuevas de la Secada, of different sizes, which serve in times of heavy rainfall to absorb the excess water. This book also has a pozo nuevo taking the water.

It was around this time that a new, apparently lower road through the depression was built. It may be that the new pot was able to prevent frequent bad flooding. The previous water levels in the depression may have been generally higher and there may be old flood sinks to discover, beyond and higher than the present Carcavuezo entrance.

References: anon., 1974b (logbook); Puig et al, 1896; Madoz Pascual, 1848; Fernández Gutiérrez Juan Carlos, 1965; anon., 1974a; Cox G, 1973; Fernández Gutiérrez J C, 1975; Cope J et al, 1976; anon., 1978 (logbook); Manchester University Speleological Society, 1982 (survey); Corrin J et al, 1978; anon., 1980a (logbook); Corrin J et al, 1981b; Corrin J, 1980; Mills L D J, 1981; Mills L D J and Waltham A C, 1981 (survey); Corrin J S and Smith P, 1981; anon., 1981 (logbook); anon., 1983b (logbook); anon., 1985b (logbook); Corrin J, 1986; anon., 1986 (logbook); Corrin J, 1987 (survey and photo); Manchester University Speleological Society, 1982 (survey); material in file; anon., 1987 (logbook); Corrin J and Knights S, 1988; anon., 1988 (logbook); Davis J and Corrin J, 1989 (photo); Cawthorne R, 1987; anon., 1989 (logbook); Neill A et al, 1989; anon., 1991 (logbook); Corrin J, 1992a (survey); Corrin J, 1992b (survey); Corrin J, 1994b (survey); anon., 1996c (Christmas logbook); anon., 1997b (logbook); Corrin Juan, 1998; Fernández Ortega F, Valls Uriol and Maria del Carmen, 1998; García José León, 1997 (survey); Corrin Juan, 1997c; anon., 1999a (Easter logbook); anon., 1999c (logbook); Corrin Juan, 2000; anon., 2001a (Easter logbook); anon., 2001c (Summer logbook); Corrin Juan, 2001a; anon., 2002c (autumn logbook); Corrin Juan, 2003a; anon., 2003c (summer logbook); Corrin Juan, 2003c; anon., 2005b (Easter & summer logbook)
Entrance pictures : yes, 1977 and 2005
Underground picture(s): Scanned slides of the sump from 1977 by Frank Addis

sump

sump

Video: stream sink   Entrance: 1  2  3  4
Detailed Survey :
Line Survey :
On area survey : 4 Valleys Survey (no details)
Survex file : download 4 Valleys System