The Sierra de Ayllón (Ayllón mountain chain) or Macizo de Ayllón (Ayllón massif) is a mountain chain of the Iberian Peninsula, belonging to the Sistema Central, of which it constitutes one of its easternmost spurs. It is located between the Spanish provinces of Guadalajara, Segovia and Madrid. The mountain chain consists of a natural area protected within the Natura 2000 network as a Site of Community Importance and Special Protection Area for Birds, located in the northwest of the province of Guadalajara in the autonomous community of Castilla-La Mancha. The natural area of Ayllón occupies the Paleozoic massif of the Sierra de Ayllón, in the province of Guadalajara, including the main core whose highest peak is the Pico del Lobo (2269 m), and the Sierras de la Concha (1865 m), Pico Ocejón (2048 m) and Alto Rey (1852 m).
The Sierra de Ayllón is the eastern end of the Sistema Central, where the bioclimatic level is dominant. Supramediterranean, with notable representations of the oromediterranean level and occasional areas of the cryo-Mediterranean. The massif was raised during the alpine orogeny, having a very broken relief, with steep slopes and a complicated and dense hydrographic system. It borders to the west with the Sierra de Somosierra and the Sierra del Rincón, to the east with the Sierra de Pela and Alto Rey mountain, to the north with the Meseta Norte and to the south with the Campiña de Guadalajara.
From its mountains rise the Jarama and Sorbe rivers, as well as other minor rivers such as the Jaramilla river, Berbellido river, Sonsaz river or del Ermito river. In its valleys grow the southernmost beech forests in Europe —Tejera Negra, La Pedrosa and Montejo beech forests—, without missing in its flora the holm oak, oak and Scotch pine. Among its fauna are wolves, vultures and small mammals. The part of the mountain chain in the province of Guadalajara is located within the Sierra Norte de Guadalajara Natural Park and the Sonsaz Hunting Reserve extends over a large part of its territory.Additional information:
Geology and lithology The outcropping materials are mainly slate and quartzites of the Ordovician and Silurian periods, with outcrops in some areas (El Cardoso, Hiendelaencina, etc.) of Precambrians gneiss. The natural area of Ayllón extends towards the south following the valleys of the main rivers (Lozoya, Jarama, Sorbe, Bornova, Cristóbal), in whose canyons habitats and communities of great ecological value are located. There are also periglacial reliefs (quartzite cliffs) and remains of glacial activity in the vicinity of Pico del Lobo.
Geological evolution Location Map
The geological evolution of the mountain chain is marked by two major foldings: on the one hand, the Hercynian orogeny, towards the Silurian period, when mountain ranges are formed throughout western Europe by huge magmatic masses that give rise mainly to granitic rocks, gneisses and slate, and the erosion of seawater that by then occupied a large part of the Iberian Peninsula; on the other hand, the alpine orogeny from the Cenozoic Era that raised again the mountain ranges of the Sistema Central and when the current hydrographic system was established, forming the valleys and the silhouettes of the mountains. The last glaciation partly affected the Macizo de Ayllón forming some glacial cirques such as those found at the source of the Berbellido river, next to the Pico del Lobo, and at the Peña Cebollera Vieja.
Lithological zones The Sierra de Ayllón is divided into three main lithological zones depending on the type of rock that predominates in each one:
Granitic zones From west to east, from Puerto de Somosierra to El Cervunal, and from north to south, from Riaza to Puerto del Cardoso, following the right bank of the Ermito river, granite abounds among the rocks that form the mountains of this area of the Sierra de Ayllón.
Gneissic zones The gneiss is, however, the least widespread of the three predominant rocks in the Sierra de Ayllón. It forms mainly in the area of El Cardoso de la Sierra to the south until the Jarama river acts as a natural boundary between the Sierra de Ayllón and the Campiña.
Slate zones The slate is the most common rock seen in the Macizo de Ayllón, as well as being the one typically used in the constructions of the villages in the area. Likewise, the slate areas can be classified according to the type of slate that gives shape:
The clayey slate extends in several mountain ridges: from El Cardoso de la Sierra towards Pico del Lobo, and from there towards Puerto de la Quesera. The dark slate is typical of the northern slope of the massif corresponding to the provinces of Segovia and Soria, from Pico de la Buitrera to Grado del Pico. Many of these areas are mixed with sandstones and agglomerates from the Triassic and Neogene periods. It also covers a wider area from the Sonsaz River to the south.
Orography and relief There are three relief units that form the Macizo de Ayllón: the peneplain, areas of undulating surface located at the ends of the massif, mainly to the north and south; the valleys, short in the north and very long and narrow in the south, leaving little room for meadows, and the mountain range itself. The mountain chain is distributed in a main ridge, which runs from west to east to the north of the mountain chain, and three secondary ridges, which leave the main one from north to south.
The main ridge runs along the north of the mountain chain from west to east, from Peña Cebollera, through Cervunal, Pico del Lobo, Puerto de la Quesera, Peña de la Quesera, Peña de la Silla, Parrejón and Pico de la Buitrera, until, losing a lot of altitude, it joins the Sierra de Pela between Grado del Pico and Villacadima. The Cebollera ridge is the most westerly, nestling between the Madarquillos and the Jarama rivers. It starts in the Cebollera Vieja towards the Cabeza del Tempraneigo and divides in two descending towards the south through Cuchar Quemado, Alto de la Fuente de Cabezuelas, Cebollera Nueva, Cerro de la Porrilla and Alto de la Dehesa de Horcajuelo up to Peña la Sisa and Pico de la Dehesilla, in the area of Horcajo, Horcajuelo and Montejo, on one side, and Collado de las Nieves, Cerro de Recuenco, Sierra de Escalba, Puerto del Cardoso, Pico de las Bañaderas, Puerto de la Hiruela and Alto del Porrejón, on the other hand. The central mountain ridges are divided by the Jarama river to the north between it and the Jaramilla river and to the south between the Jarama and the Lozoya river. They are mountains, in general, of lower altitude. They are composed by several hills: One runs from the Cevurnal towards Majada de los Carneros, Cabeza Pinillo, Cerrón and Santuy to the banks of the Berbellido river. Another, from Las Peñuelas down through La Cebosa and Pico del Águila, Morra del Segoviano, Cabeza Grande, Cerrajo and Cerro de Corralejo to the mouth of the Jaramilla river in the Jarama. To the south are the lower elevations, distributed anarchically, such as Cerro San Cristóbal, Pico de la Tornera, Pico de la Centenera, Cabezas and Palancar. The eastern ridge is the most important of the secondary ridges. Although only Pico de Ocejón exceeds 2000m of altitude, most of its mountains rise around 1700m and 1900m. There are several hills that also form this ridge: The main hill is the one that forms the Sierra del Ocejón. From Pico del Granero, Tiñosa, Corralón and Atalaya it extends between the rivers Jaramilla and Sonsaz to the south by Cabezo de San Pedro, Regajo de las Yeguas, Cerrito Collado, Campachuelo, Campo and Pico de Ocejón. The Loma de Pinarejo from Atalaya to the southeast through the Cabeza Arca and Pinarejo to the banks of the Sorbe. Other smaller hills, such as Las Llanadas and Bubillejo, arise from this area. The Loma de la Torrecilla is the center of the Tejera Negra beech forest, forming the right bank of the Lillas river. From Cervunalillo through Alto de la Escaleruela and Alto del Hornillo to where the Sorbe takes its name.
The "two-thousands" of the Sierra de Ayllón In the heart of the Sierra de Ayllón rise the last peaks of more than 2000 meters of the Sistema Central. MountainSubsidiary ofHeightRidgeProvinceLocationPico del Lobo—2272 mMainGuadalajara and SegoviaAlto de las MesasPico del Lobo2257 mMainGuadalajara and SegoviaBuitrera de los Lobos, S peakPico del Lobo2221 mMainGuadalajaraBuitrera de los Lobos, S-SE peakPico del Lobo2215 mMainGuadalajaraLas Pañuelas, central peak—2211 mMainGuadalajara and SegoviaLas Pañuelas, W peakLas Pañuelas, main peak2204 mMainGuadalajara and SegoviaCerrón—2197 mCentralGuadalajaraLas Pañuelas, E peakLas Pañuelas, main peak2194 mMainGuadalajara and SegoviaEl CervunalPico del Lobo2194 mMainGuadalajara and SegoviaPeña Cebollera Vieja or Tres Provincias—2129 mMainGuadalajara, Segovia and MadridPeña de los AbantosCebollera Vieja2124 mCebolleraGuadalajara and MadridCerro de la Majada de los Carneros—2078 mCentralGuadalajaraCabeza del Tempraniego or La Pedriza—2071 mCebolleraGuadalajara and MadridPeñon de MatarredondaCerrón2065 mCentralGuadalajaraLoma de Cabeza Pinillo—2061 mCentralGuadalajaraEl RocínLa Cebosa2051 mCentralGuadalajaraPico Ocejón—2049 mEasternGuadalajaraLa Cebosa—2048 mCentralGuadalajaraCoto de Montejo, El Corco or Cuchar Quemado—2047 mCebolleraMadridCerro del Picaño—2046 mCentralGuadalajaraPico de la Buitriera—2038 mMainGuadalajara and SegoviaCerro del Picaño, W peakCerro del Picaño, central peak2033 mCentralGuadalajaraLoma de Cabeza Pinillo, E peakLoma del Picaño, central peak2032 mCentralGuadalajaraCerro de Mesa PeñotaPico de la Buitrera2026 mCentralGuadalajara and SegoviaAlto del Cervunalillo—2018 mMainGuadalajara and SegoviaAlto del Parrejón—2017 mMainGuadalajara and SegoviaCerro OrtigosaCerro del Picaño y Cerrón2011 mCentralGuadalajaraCerro del Picaño, SE peakCerro Picaño, central peak2008 mCentralGuadalajaraCerro del AventureroLas Pañuelas, central peak2003 mMainGuadalajara and Segovia
Other outstanding peaks MountainHeightRidgeProvinceLocationPeña de la Tiñosa or Pico del Granero1971 mMainGuadalajaraPeña de la Silla1937 mMainGuadalajara and SegoviaSatuy or Cerro de la Calahorra1927 mCentralGuadalajaraCampo1919 mEasternGuadalajaraCampachuelo1899 mEasternGuadalajaraAtalaya1884 mEasternGuadalajaraPico de la Tornera1865 mCentralGuadalajara and MadridCebollera Nueva1834 mCebolleraMadridPeña de la Cabra1831 mCentralMadridPico de la Centenera1809 mCentralGuadalajara and MadridValdebecerril1766 mMainGuadalajara and SegoviaMajada de la Sierra1695 mMainGuadalajaraLoma del Pinarejo1694 mEasternGuadalajaraPico del Águila1650 mCentralGuadalajaraCabeza de Cabida1597 mCentralGuadalajaraCerro San Cristóbal1588 mCentralGuadalajaraAlto de las Cabras1543 mEasternGuadalajaraCabeza de Ranas1492 mEasternGuadalajaraCabezas1437 mCentralGuadalajara
Climate
The mountain climate of the Sierra de Ayllón is marked by two fundamental factors: on the one hand, the latitude, marking the Mediterranean character with hot summers and low rainfall; on the other hand, the orientation of the massif causes the interception of the low-pressure areas of Atlantic origin bringing with it a greater rainfall on the northern slopes than in the south. This second factor, together with the fact that the northern slopes receive less sunlight and, therefore, maintain a lower temperature, leads to a greater accumulation of snow in winter on the northern slopes than on the southern slopes.
The heaviest rainfall occurs in winter, usually in the form of snow, coinciding with the summer, a long dry season. The average annual rainfall is between 800 and 1000 mm.