This there and back walk takes you from the pretty white village of Presillas Bajas up a dry rambla and into a long extinct volcano in the Cabo de Gata. The desert landscape is awe inspring.
Start and Finish: Presillas Bajas
Distance: 8 kilometres.
Essential: Boots, food and water.
Notes. Walking in the Cabo de Gata is only recommended from November to April. Even then take plenty of water, one litre for every two hours you are walking. Wear a brimmed hat and allow more time for any walk. The walk described is an 8 kilometre round trip for which you should allow 4 hours.
Park in Presillas Bajas and walk down to the dried up streambed. This is the Rambla de Majada Redondo. Its deep cut banks are the result of water erosion. It may not flow for years at a time but when it does the result is catastrophic for anything in its path. Between periods of intense activity the water retreats to far below the surface from where it has to be drawn by the norias or Arabic water mills, you see all over the Cabo de Gata.
Follow the rambla as it gently ascends between two hills, the one to your right, Cerro de Majada Redonda, is actually on the caldera although you will not realise that until you arrive at the central cone. At the moment you are skirting around the outside of the caldera.
Keep an eye open for basalt bombs. These are as a result of magma being shot into the atmosphere to a great height. There they cool into a teardrop shape that then falls back to earth. Some bombs are only a few centimetres long whilst others can be metres long and weigh many tons. The bomb from which the piece in the photograph came was one of the latter. When it landed it created a crater for itself that was then filled with material that protected it from subsequent erosion. Until now that is. The bomb has been exposed to the air and, sometime during the last winter, the succeeding daily cycle of hot days and cold nights has chipped off a piece, erosion in action.
A little further and you will see that the rambla has eroded down through a layer of pale grey soft volcanic rock that contains flecks of a dark green mineral. This is solidified magma that flowed from the volcano. It is called dacite. High in silica, when extruded at 8000C to 10000C it contained little gas so as it cooled it formed the fairly smooth consistency you see today. It was also a viscous magma so tended not to flow very far before solidifying. Further north similar deposits have been exploited for the garnets they contain.
Shortly afterwards you should see a deep fissure in the left hand bank of the rambla. Originally a narrow slot it has been widened by man, probably during the Moorish occupation. Looking into it carefully you will see, about ten metres down, a pool of water. Water from a subterranean stream like this is brought to the surface by the noria in the centre of the nearby village, El Pozo de los Frailes.
The way becomes steeper as the sides of the rambla close in. Agave plants lean precariously over the side, threatening at any moment to topple over and block the way. In the banks plants cling precariously to life, flowering only after precipitation. Strictly speaking the Cabo de Gata is not a desert, it is known as a semi arid zone due to the consistently high humidity levels, over 75%, caused by cold air from the inland Sierra Nevadas flowing down off the mountains to meet the warm, water saturated Mediterranean air. There is heavy dew on the majority of nights and it is this dew that keeps many of these succulent plants alive between rains that can be many years apart. The ramblas, being depressions, tend to receive more dew than the surrounding land, hence the more luxurious vegetation.
The way gently swings to the northeast and you walk between two steep hills and into a confused landscape of hummocks through which the rambla twists and turns, eventually emerging in more open ground with a cone shaped, low hill to the left. Make the effort to climb this for it is the central cone. From its summit you have a panoramic view of the inside of the caldera with just one break in it, the gap through which you came and through which you must return.