THE MOST IMPORTANT CAVES OF URZULEI/h3>
We can distinguish two different karst areas in Urzulei, one East and the other West, separated by a clear strip of Paleozoic granitic and metamorphic rocks. A total of over 300 caves have been registered in these two areas. In the following paragraphs we will describe the most important of these caves, starting South and moving northward, like the flow direction of the waters that are at their origin.
Di seguito si da una sintetica descrizione delle grotte più significative che sono elencate da sud verso nord secondo il senso incui scorrono gran parte delle acque sotterranee artefici della loro formazione.
CAVES OF SUPRAMONTE
“Sa Rutta ‘e S’Edera” Cave (Urzulei)
Sa Rutta ‘e S’edera opens in the location called Fennau and is the upstream part of probably the biggest Sardinian cave system, which connects the caves of the South to the northern Su Gologone resurgence. S’Edera has a development of around 13 km for a depth of 250 metres and has the typical morphologies of most of the Supramonte caves. The active part is characterised by meanders, potholes, waterfalls and a series of complicated rockfalls. In the upper fossil parts the rooms are big and well decorated with very beautiful and also fragile speleothems.
Cave progression is rather complicated, and Edera is probably among the most technical caves in Sardinia. Average cave temperature is around 9°C. Air flow is very strong in the active parts of the cave, together with the presence of an active stream, making long stops rather unpleasant. Being an active sinkhole, its visit can be dangerous especially during and after long rainy periods.
Orbisi sinking stream Cave (regional cave register “inghiottitoio di Orbisi”) (Urzulei)
The cave opens on the left flank of the Rio Orbisi valley, and develops over approximately 800 metres. During long rainy periods, it becomes an active sinking stream, and its final sump is connected to the nearby Luigi Donini Cave. It is characterised by a network of phreatic tubes in limestone that connect to a main passage with some lakes and ending in the final sump. Cave progression is very simple and does not
require the use of ropes.
Luigi Donini Cave (Urzulei)
The cave is an active through flow cave with a sinkhole (Orbisi) and a spring. It has four different accesses, distributed evenly along the cave (Pitt’e Rutta, Via del Mondo, Su Cunn’e S’Ebba and the fossil exit). The cave develops over 3 km for a depth of only 100 metres, and is connected to the upstream Orbisi sinking stream cave. The cave is composed of a main branch characterised by a long succession of deep lakes and
some small drops (descent in double rope). During floods the cave hosts a furious river that exits at the place called Su Cunn’e S’Ebba, high on the limestone caves on the right flank of Orbisi canyon, just a couple of km upstream of Gorropu gorge.
Giuseppe Sardu Cave (Urzulei)
Deep cave (-180 m) that opens on the right flank of the Gorropu canyon. Known to shepherds since a long time, its entrances are rather hidden, and because of this it was explored only in the 90s. This is the northernmost important cave of Urzulei, connected to the main cave system of Supramonte, and represents an enigmatic part of the hydrogeological rebus. The cave has two entrances at different altitude, and develops vertically into a wide room in which a waterfall falls in a lake-sump. This room is filled partially during the floods, when water flows in the Gorropu canyon, with a water level rising over more than 10 metres.
CAVES OF RIO FLUMINEDDU (Supramonte)
Here we describe the four most important caves of the area, among the deepest in Sardinia, that together reach a development of more than 13 km. All these caves open on the right flank in the Rio Flumineddu valley. The most upstream cave is Mandara e S’Uru Manna, being also the first being discovered. Going downstream we find Su Colostrargiu, then S’Orale de su Mudrecu and finally s’Eni de Istettai. All these caves are very technical, and required many years of intensive and hard caving. They are all part of the main cave system of Supramonte, and their streams are connected to the Su Gologone Spring. They are characterised by low temperatures, only slightly above 9°C, by their vertical initial parts, and by aquatic passages with rockfalls and narrow passages that partially obstruct their horizontal stream passages.
CAVES IN THE RIO CODULA ‘E LUNE AREA
“Su Prediargiu” Cave (Regional cave register: “Suttaterra de su Predargiu”) (Urzulei).
This cave is only 600 metres long and opens at the contact between the basement rocks and the dolostones, on the western flank of the Serra Oseli ridge, high above the Rio Codula ‘e Lune. It has a rather short part that leads to a larger room characterised by the presence of very beautiful and delicate aragonite speleothems, among the prettiest of Sardinia.
“Su Crabargiu” Cave (Urzulei)
The cave opens in Bacu Su Palu, one of the side branches of Rio Codula ‘e Lune (Urzulei). It has a very large entrance with a 1000-year old olive tree in front. The cave is characterised by rooms developed along fractures and, in its inner parts, it hosts spectacular columns, stalagmites, gours and stalactites. In the deepest parts, there is a small water flow that passes through a complicated network of boulders..
Su Palu Cave (Urzulei)
The entrance of Su Palu Cave is located above a debris slope on the right side of the Codula ‘e Lune valley, in front of Bacu Su Palu, and is closed by a gate. The cave is the upstream part of the longest Italian cave system that develops over more than 70 km, and connects the caves of Su Palu, Monte Longos, Su Molente, and Bue Marino. Inside Su Palu two main rivers join in a great lake, from where a sump connects it with
Monte Longos Cave. This river then flows downstream for many km reaching the Tyrrhenian Sea at the Cala Luna springs. Su Palu has several stacked cave levels with different morphologies. One of the most characteristic passages is the semi-sump, an obliged passage only 400 metres inside the cave, that has to be passed if you want to visit the deeper parts of the cave. Alta Loma, the waterfall, El Alamein cave camp, and the famous and enormous Lilliput Gallery are some of the noteworthy places to visit.