As we have made clear, la Sierra de las Nieves and surroundings have an important geological complexity, because the different age and origin of the materials and the movements and relations that these materials have suffered along the history.

That geological complexity, easily identifiable by any expert, is obvious as well for any visitor who is a little observer.
Putting a little attention on the lands in la Sierra de las Nieves, we realize of the big contrasts made by three different landscapes clearly different:The White Sierras.
They are formed by large masses of limestone rocks and dolomites, with a greyish and whitish aspect, which are the main mountains of the area. Erosion, and specially water erosion, provokes in this kind of rocks a peculiar modelling called Karstico. In these karsts, are elements really singular in their two levels:
One on the surface, where cannons, clefts, cuts, etc., motivated by the existence of fractures, cross big rock masses drops, descents, and movements of the lands.
The other is underground, where an endless of tunnels, galleries and deep pits created by the chemical erosion of the CO2 of the water give to this kind of rocks. To this underground level belong the deepest abysses in Europe: the GESM abyss and the Chasm of the Air, both located in la Sierra de las Nieves.

The Red Sierras
Mainly compound by peridotite rocks, which become red when reach the surface because of the oxidation of the iron present in these types of stone. This stone originates thin and lack of nutrients flooring, where only a few species of pines and brushwood can grow. The contrast between the White and the Red sierras is very patent in many places in the Reserve.

The Dun Lands.
Clay and some metamorphic materials dominate these lands. In most cases, these materials are located in the lower lands, with a softer climate and deeper flooring. So that this landscape is the most modified by the human action, which have changed the original vegetation into croplands. On its waving shape, the colours go from the red of the clay, to the changing crops of cereals, almonds and olives.

Geology
The sierras of the Reserve of the Biosphere in La Sierra de las Nieves and surroundings are integrated in the big mountain range named Beticas, at its most occidental part.
All the Reserve has a complex topography in the composition and origin of the materials, as well as in the morphology what with these materials interrelate.
Mainly we have to point out the sedimentary originated materials that compound the main mountain masses. Big lime rocks and dolomites, with several kilometres thick, are the principal part of the sierra.
These materials, from large sedimentary deposits accumulated under the sea in millions of years, were emerged and fractured by the enormous tectonic strengths in result of the collision of the African and Euro Asiatic plaques in the so-called Alpine Bent.
Other remarkable element is the predictive, curious rocks that outcrop in huge compact masses in the Reserve, acquiring reddish and greenish colours on the surface. These rocks have a plutonic origin, which means a deep magma that by the effects of the inner strengths irrupted in the lime rocks. This intrusion provoked as well another phenomenon, the metamorphism, resulting marbles from the limes, and esquistos from the clay. In those places where the erosion or the later movements haven’t had effect, is still visible a ring that separate the periodite from the lime rocks and other materials.

Another great material groups are the clay lands. Most of them compound by margas a margelimes, appear in lower areas, and they are occupied by agricultural activities.
Finally, the effects of the physical and mechanical meteoric actions, to which the materials on the surface are exposed, have had an important part in the modelling and shaping of these lands until get the actual aspect.

Biosphere
In 1971, and because of the increasing in the preoccupation on the natural world deterioration produced by the man in all the world, the UNESCO started the program “man and biosphere” (MaB), with the focusing on the studio of the way that the human specie affected the biosphere, and determine solutions to avoid it.
It was when, under this program, were created the first Reserves of the Biosphere. These reserves are places with exclusive natural richness, which are representative of the different areas of the world, and where are carried out programs to help the social and economical development of the local population.
On June, 15th, 1995, la Sierra de las Nieves, got the privilege and the honour of being declared a Reserve of the Biosphere by the UNESCO, after a local initiative, and attending three main functions:
Conservation of its landscapes, ecosystems and diversity of species and genetic resources.
Social, economical and human development of the inhabitants in an ecologic and cultural sustainable way.
Scientific investigation, formative and educative plans focused on the conservation and sustainable development, on local, regional, national and international policies.
The Reserve of the Biosphere of la Sierra de las Nieves and surrounding is 93.930 hectares and is composed by the villages of Alozaina, Casarabonela, El Burgo, Guaro, Istán, Monda, Ojén, Parauta, Tolox and Yunquera, and a part of Ronda.

The Reserve bases its structure in the existence of the Sierra de las Nieves Natural Park, declared in 1989, with a total extension of 20.005 hectares. The Natural park, integrated in the Andalusian Natural Spaces Net, has a specific set of laws to protect the main ecosystems of the zone, as well as the landscapes, the flora and the fauna, to warrant its conservation.
The Reserve of the Biosphere is organized in three kinds of areas, depending on the use allowed in each one.
The nucleus areas. In there are the most important ecologic values of the Reserve, being included in the Natural Park, so that, they have a big protection, warranting this way the conservation for long time. The Spanish fir forests, the areas of the mountain Quejigo, and other special ecosystems like the “cornicabrales”, are in these nucleus areas. In there, the human activity is limited to the research and investigation of natural phenomenon, and those related to the environmental education.

The tampon areas. These areas have important values as well, so that they have the adequate protection, although not always under the figure of the Natural Park. Crops, forest exploitation, environmental education, or tourism, are common activities in these areas, but always being respectful with the environment and avoiding the possibility of negative effects on the section.
Transition areas. These are areas where the human activity has been present for centuries, changing the landscape. Although there is a lower ecologic interest, these areas have a strong social and economic meaning, because there take place the most of the resources exploitation by the inhabitants of the zone, and the most archaeological remains can be found. The villages, the crops, and low impact industrial activities take place in here, helping this way to protect the other areas.
So that, la Sierra de las Nieves have become a living showcase of the living together of Men and Nature, and have been integrated in the International Reserves of the Biosphere, to preserve the bio-diversity.