Slate deposits of Spain

Spain with its ten slate districts is the worldwide most important producer of (roofing-) slate and most of the slate regions lie in the Galician provinces (see Fig.). In Spain one can distinguish the following slate districts:

The slate district of Monte Rande (1) in the northern part of the Province La Coruña. Close to the village Ortigueira lies a large slate quarry where the black slates of the Middle-Ordovician 'Luarca Formation' are mined. This quarry is situated within the western part of the anticlinorium 'Ollo de Sapo' within Galician-Castillian Zone. Both, the bedding plane and the fracture cleavage plane steep almost vertical.

The slate district of A Terra Cha (2) stretches over the center of the Lugo province and owes its name to the smooth topography. There are several slate quarries close to the villages of Mondoñedo, Lorenzana, Pastoriza and Pol. In this quarries green phyllitic slates ('Lugo Verde'/'Lugo Green') and, less important, grey slates are mined. The slate deposits lie within the Leon-West-Asturian-Zone and the slates mined belong to the Lower-Cambrian 'Candana Series'.

At the border between the Lugo province and Asturia one can find the slate district of Los Oscos (3). Slate mining is carried out close to the village of Villarcho (Lugo) within the Middle-Ordovician 'Luarca Formation'. The slate deposits is situated in the Leon-West-Asturian-Zone between the 'Manto de Mondoñedo thrust' and the 'Narcea anticlinorium'.

The slate districts of El Caurel (4), Valdeorras (6) and La Cabrera (7) will described more thoroughly in the following chapters because they are the economically most important slate districts.

The slate district of Alto Bierzo (5) comprises the slate deposits of the regions of Anllares, Paramo del Sil and San Pedro de Olleros in the León province. The slates of the Middle-Ordovician 'Luarca Formation' lie within the 'Narcea Anticlinorium' which is situated within the Leon-West-Asturian-Zone.

Spanish slate districts

Several slate quarries lie west of the Zamora province in the river valley of Aliste (8) which gave this slate district its name. It is situated in the Galician-Castillian-Zone within the 'Alcañices syncline', comprising Middle- to Upper Ordovician rock units (?). The slates show a black and grey colour.

In the Segovia province within the Galician-Castillian-Zone two slate deposits exist close to the city of Bernados (9). The slates are mined in Paleozoic beds and this phyllitic slates show an intense silification and a greenish colour with intercalated black slates. They are assigned to the Upper-Precambrian to Lower-Cambrian 'Greywacke Slate Complex'.

The slate deposits of Villar del Rey (10) lie in the northern part of the Bajadoz province at the border between the eastern Lusitanian-Alcudian-Zone and Ossa-Morena-Zone. Slates are mined in Lower-Ordovician to Middle-Devonian units within the synclinorium of 'Sao Mameda-La Codosera'.