Sierra de Malagon
Sierra de Malagón is a mountain range located geographically within the Sierra de Guadarrama, which in turn belongs to the Central System of the Iberian Peninsula.
Description
To the south and west of the port of Guadarrama rises the Malagón block, a quadrangular morphostructure that constitutes the main element of transition or link with the great mountain range of Gredos and the Parameras de Ávila.
The eastern edge of this complex relief presents great continuity with the alignment of La Peñota and is defined as a horst that rises above the southern piedmont of the Central System following NNE faults. From the aforementioned Peñota to the south, the summits and slopes are granitic, but to the south of Cuelgamuros it is the gneisses of the metamorphic outcrop of El Escorial-Villa del Prado that form the sierras of San Juan (1735 m) and Abantos (1757 m).. The fault of Santa María de la Alameda, another of the great Hercynian thrusts, has been recognized in them. On the flanks of the Hercynian folds, marked in these gneisses, some secondary relief forms have been indicated, but these alignments are fundamentally asymmetrical horsts that rise above the ramps of the El Escorial foothills and link up with the culminating surfaces of the Malagón back. To the south of El Escorial, the small horst of Las Machotas constitutes a semi-domedtic granite relief of very intricate topography. Similar morphostructures appear to the south, also marking the Malagón block: it is a series of "morros" granite and the long alignment of the Almenara (1259 m) that constitutes the eastern edge of the Robledo de Chavela pit.
The northern edge of the Malagón block is part of the sierra of the same name, which, like the previous one, is asymmetric; in this case, the northern edge of the block is an escarpment that rises above the El Espinar and Voltoya trenches. The maximum uplift is located in the eastern sector, where this mountain range connects with the Guadarrama itself at Cabeza Líjar (1824 m), culminating in Cueva Valiente (1904 m). The slope that closes the El Espinar depression to the south is the highest and steepest, appearing transversally cut by NE faults. To the east, the slope advances towards the north at the buttress of Cabeza Renales (1757 m) which serves as the limit between this pit and the one of the Voltoya in an E-W direction. This head serves, therefore, as a limit to the two pits and, to the south of it, the relief of Malagón is losing height. The aforementioned pits are closed to the north by a group of hills that isolate them from the slopes of the foothills: those of Caloco (1567 m) and Rinconada (1358 m) close the depression of El Espinar; those of Peña Morena and Atalaya (1506 m), that of Voltoya. To the west of this trench, the small Ojos Albos mountain range of Avila (Cruz de Hierro 1660 m), made up mainly of Ordovician quartzite and slate, closes the depression along another NE fracture, the Paramera de Ávila-Cruz de Hierro fault..
The so-called "back" The Malagón block constitutes a kind of inclined plane towards the SSW, modeled in its culminating areas by erosion surfaces and internally articulated by a set of orthogonal trend fractures. Throughout the most active there have been unevennesses that have not broken the general physiognomy of the erosion surfaces, and that have been highlighted by the rivers that fit into gorges such as those of Cofio and those of the Aceña river.
It ends to the west of the N-S El Herradón fault and, to the south, with the El Tiemblo-Cebreros-San Martín depression, cut by the Alberche river (which crosses it to exit the Tagus basin, extending to the Parameras de Ávila, with which it connects by the Cuerda de los Polvisos
The northern slope of the Sierra de Malagón is smooth in some points and broken in others, quickly passing to the great plain of Campo Azálvaro, already in Segovian lands. Its southern slope, on the contrary, is more extensive. Its buttresses, aligned from north to south, gradually lose altitude until they practically reach the left bank of the Alberche river. In these foothills there are rough peaks, steep slopes and few plains, with smooth spaces between cols, hills and ravines that take the name of holes or navas. A multitude of valleys and small streams furrow the term, contributing their irregular flows to the Cofio.