Geoturism Balearic Islands

Optionally, you can continue with the trail by accessing the Es Torretó public farmhouse along Camí Reial. To get there, carry on along the slope that gave access to the last stopping point, which is a 1.5 km walk as far as the Es Torretó summer camp farmhouses. After this, the suggested route is 0.5 km. At this farmhouse, you will find a signposted botanical trail that was created as part of the Island Council of Menorca’s LIFE+Reneix project. As the lands of this farmhouse are at the top of the slopes of the ravine, we recommend coming here to visit the belvedere, from where you get some superb views of it.

Following the route of the farmhouse, before reaching the belvedere, you will see a temporary pool. Temporary pools are one of the most unique and exclusive habitats of the Mediterranean. They are aquatic environments that are fed exclusively by rainwater that accumulates in depressions in the ground, and their dynamic of times of flood and drought is often irregular, as is the Mediterranean climate itself. This forces a large part of the living beings that live in them to specialise, hence their biodiversity being exclusive and changing from one season to another.

In Menorca, due to the great diversity of geological substrata, we find very different types of temporary pools, which have a specific flora and fauna associated with them depending on the characteristics of the soil, the chemical composition of the water, the length of flooding, etc.

If a temporary pool is a small depression formed naturally on impermeable land, it seems contradictory that many of them are situated on the permeable materials of the Miocene, which, as was explained at the second stopping point on the trail, make up the most important aquifer on the island as they allow rainwater to infiltrate.

The impermeability of the rocks where these pools form is attained through diagenetic processes, such as that of cementation near the surface where a Sedimentary rock whose main component is calcium carbonate (CaCO3). Its origin can be chemical, organic or detritic.</p><p><br></p></div>">limestone crust is created when evaporation exceeds rainfall. We should also remember that the impermeability of the temporary pools on marès may be due to their being filled with clays from an external source. This would be the same case as watering places for livestock (although in this case due to anthropic actions), which, made of marès (very permeable) are covered in clay or lime to prevent loss of water.

On reaching the belvedere, you can look at the wonderful view that you get of the ravine, dominated by the height of the ravine’s nearly vertical walls, between which terraces have been put in for crops, especially fruit trees. Next to the cliff you will see how the most has been made of spaces where erosion has especially affected its lower part, creating entrances where buildings have been constructed.

These deep ravines are only found in the central part of Menorca’s Migjorn region. This is because the region is slightly convex due to the action of tectonic movements, with maximum rising in this central part (area with the most curvature), forming what in geology is known as an anticlinal structure. Associated with the rising of this central part is the appearance of a series of fractures, which, as they are in the weakest areas of the rock, would be used by the streams to establish themselves and affect the Tramuntana area. As well as all these tectonic movements, we should remember the drops in sea levels that occurred worldwide during the Quaternary, which led to a rise in the slope and consequently gave the streams great erosive power sweeping and dragging rocks and sediments towards the sea. A later rise in sea levels some 10,000 years ago stopped and reversed this process, in other words, it created the stream’s generalised sedimentation in its lower reaches and filled the coves with sediments.

We should point out that the numerous twists and turns described by the ravine, its meanders, can be associated with large collapses. The dissolving of the Sedimentary rock whose main component is calcium carbonate (CaCO3). Its origin can be chemical, organic or detritic.</p><p><br></p></div>">limestone rocks by subterranean waters and the subsequent creation of cavities could have caused the collapse of the land at the time that the cavity was so big that it is unable to support the weight on top of it. In other words, the dissolving of the rock can cause the cave ceiling to collapse, forming circular depressions of varying sizes known as sinkholes, which occurred on the sides of the ravine, so widening its river bed.

Evolution of the Migjorn region that would lead to the formation of the deep ravines in its central area. Marine sedimentation in the Migjorn region during the Miocene was created by its sinking compared with the Tramuntana (1). In the late Neogene – early Quaternary, the region gently folded, favouring the appearance of fractures in the area with the greatest curvature (central area of the region) (2). These fractures were used by the drainage system due to their layout, which even went as far as the Tramuntana area, so favouring their incision to create a larger area and the formation of the deep ravines at a time when sea levels were lower (3) (modified from Gelabert et al., 2005).