| UTM-X | UTM-Y | ||
|---|---|---|---|
| STOP 1: CALA BANYALBUFAR | |||
| STOP 2: TORRE DES VERGER | |||
| STOP 3: CALA ESTELLENCS |
Recommended route.
This is the most evident and most easily observed stratigraphic series.</p></div>">paleorelief of the island of Mallorca.
In the coastal cliff of Cala Estellencs we can see two very different types of materials: reddish rocks arranged in inclined layers and a granular deposit covering them.
The surface that separates the two materials is not horizontal but displays a concave form because it corresponds to an ancient channel excavated by a watercourse that has subsequently been filled in. This is therefore a fossil relief or stratigraphic series.</p></div>">paleorelief.
General view of the paleorelief of Cala Estellencs, showing its concave morphology.
The sediments deposited over the stratigraphic series.</p></div>">paleorelief are formed by powerful conglomerates of the Quaternary (2.5 Ma-present). Their dimensions range from a few centimetres to several metres, which indicate the great energy of the watercourse that created the deposit, much greater than the one that exists today, which is observed almost at the start of the cove.
The origin of the rocks which form it is very varied, because it proceeds from the erosion of the reliefs that surround the cove. Being situated nearby, these have undergone little transportation, so there is a large variety of sizes and shapes.
The underlying rocks are much older red sandstones, from the Triassic, of some 245 Ma. Although they were originally deposited horizontally, like the conglomerates, they have been affected by tectonic processes that have tilted them.
In the sandstones we can see laminations that cut across each other: this is called cross-stratification. In this case, this type of stratification tells us that the sand that composes the sandstones was dragged and accumulated by fluvial currents.
Genesis of the paleorelief observed in Cala Estellencs.
Their red colour is due to their high degree of oxidation. Their principal component, minerals of the silicates group, is atypical in the geological record of the island, where the carbonates predominate. This is because the sediment proceeds from the erosion of ancient reliefs composed of siliceous rocks.
At the northern end of the cove, and above the red sandstones, there appear sandstones of lighter colours, normally whitish and greenish (see photograph below). In these same strata, in the proximity of Cala Estellencs, vegetal remains, insects, fishes and prints of reptiles have been found, making this one of the most important paleontological sites of this epoch.
Cross-stratification of the red sandstones of the Buntsandstein in the proximity of the jetty
In addition to the materials described above, the southern end of Cala Estellencs is one of the few places of the northern coast where we can observe fossilised dunes, which are very common in other parts of the island. In the same zone there appear deposits of Sedimentary rock originated by the precipitation of calcium carbonate from supersaturated waters, especially in zones of karstic emergences.</p></div>">travertine, a very porous type of rock formed by the precipitation of carbonates in waterfalls, which fossilises the plants onto which it precipitates.
Due to the erosion processes, there are frequent falls of the rocky blocks that compose the Quaternary conglomerates and occasionally of the Triassic rocks which constitute the cliffs. To prevent these rockfalls from reaching the cove, which has many visitors in summer, a series of protective measures have been installed.
Detail of the protective measures (in the foreground the dynamic screen and in the background, to the right, the triple-torsion mesh).
To sustain the conglomerates, a triple-torsion steel mesh has been installed, fixed to the upper and lower part of the embankment.
In contrast, the large blocks of Triassic sandstones have been fixed to the embankment by means of steel bars (anchorages).
Finally, in the zone of the fishermen’s huts, a large dynamic retention screen has been installed.
