Minas de Argemela e Recheira
Categoria temática:Província metalogénica W-Sn ibérica
Proponente(s):Alexandre Lima
Contacto:allima@fc.up.pt
Região:Centro
Município:Fundão Freguesia:Barco
Área do Geossítio (aprox.):3500 m2
Coord. Geográficas:40.1666667,-7.6238889
Área de protecção:0 m2
Regime de propriedade:privado
Regime de protecção ambiental:
Incluído noutros regimes de protecção- em actualização
Avaliação quantitativa do valor científico (0-100):36.25
Avaliação quantitativa da vulnerabilidade (100-400):110
Justificação do valor científico:
Argemela and Recheira are located in the Central Iberian Zone (CIZ) of the Iberian Massif, and are easily accessible by Highway A23 and local roads. At Argemela we can see very nice outcrops of quartz veins and underground works and at Recheira the well preserved mining installations that mined these kinds of veins. At Argemela there is an exploration project under development, and in Recheira a recent project to do a Museum is being developed.
The Argemela and Recheira mines are included in a regional flysch sequence named Xistos das Beiras. To the North and South of the Argemela Microgranite (Charoy & Noronha 1996) we have the post tectonic porphyric biotitic granite of Covilhã and Vale Prazeres, Idanha-a-Nova surrounded by a contact metamorphic aureole.
The region was affected by the Sardian folding that gives origin to a NE/SW folds without visible axial cleavage. The first Hercinian phase developed folds with schistosity NW/SE dipping 60-80º to SW, with high deep axles due to the superimposition of folding and stretch of the a cinematic axle. This Hercinian folding is generally followed by regional metamorphism with green schists, chlorite zone. After all the folding phases a system of veins was installed which veins cross all the structures described before. The quartz veins are sub-vertical and usually with widths from 5-30cm, separated 1m in average and with different orientations. In these veins cassiterite, stannite, chalcopyrite, arsenopyrite, pyrite, pyrrhotite, and triphylite occur and becoming very rich in amblygonite with deepness. A second generation of mineralising fluids make the occurrence of vivianite and carbonates. The microgranitic veins intersected by the drills are cute by the quartz veins and veinlets that appear to be from a distinct generation, rich in Arsenopyrite and other sulphides (Inverno 1980).
The mining works allow the individualisation of two richer areas, one in North and another one corresponding to the South mineralised zone of Norris (1962). To these areas it was attributed a total of proven resources of 6 million tonnes with 0.8 kg Sn/t.
Charoy B. & Noronha F. (1996) Multistage growth of a rare element, volatile-rich microgranite at Argemela (Portugal) Journal of Petrology. V37 p. 73-94
Norris, D. (1962) - Report on history of operations of Argemela (Relatorio inedito)
Hosking, K.F.G. (1959) - A geochemical reconnaissance survey at Minas da Argemela, Portugal. The Camborne School of Mines Magazine
Ribeiro, A. Conde, L. E Carvalho, D. (1974) - Re1atorio da visita efectuada às Minas da Argemela (Relatorio inedito). 5pp.
Inverno, C. (1980) Estudo Geológico-Estrutural nas Sondagens das Minas da Argemela Relatório Inédito. 17 pp.
Inverno, C. & Ribeiro, M. L., 1980 Fracturacão e cortejo filoneano nas Minas da Argemela (Fundão). Commission Service Geologique du Portugal 66, 185-19
Outros valores e sua justificação:
Traditional mining buildings with beautiful mountain panorama (Estrela Mountain) and river margin (Zêzere river).
There is a project from FELMICA private company to promote Recheira Mining Buildings as an Interpretation Museum (Geological, Mining, Archaeological, etc)
Observações:
