Geossítios
GEO

Martinlongo – Vaqueiros geological section

justificação do valor científico

The region of Martinlongo-Vaqueiros, on the South Portuguese Zone, is characterized by the presence of Mértola formation turbiditic sediments (s.l.), which include dark gray shales and graywackes, sometimes with fragments of black shales, siltites, pelites and thin beds of microconglomerates (Oliveira 1988). There are also beds of generally highly fissile ferruginous shales, with thin siltite layers and centimetric nodules/lenticular of siltitic-carbonatic nature (Matos et al. 2003). Occasionally these lithologies host fossils of Goniatites (Lyrogoniatites), which indicate an Upper Viséan age (Oliveira e Wagner-Gentis 1983). In the region of the Cova dos Mouros mining park there occur plant fossils (Calamites), in micaceous graywackes and sometimes microconglomerates. The contact between the Mértola and Mira formations (to the SW) lies near Vaqueiros. The general strike is NW-SE. The Martinlongo-Vaqueiros section is one of the best locations to observe sedimentary sequences and the structural pattern of the Mértola formation, near the contact with the Mira formation (Matos et al. 2003, Oliveira e Matos 2004). Along the highway it is also possible to observe the Cerro do Aviador overthrust and late Variscan faults locally containing copper mineralization. Finally, there are late mafic dikes.
The visit to the old Ferrarias mine, presently the Cova dos Mouros mining park, consists on a 1000 m walking trail, along the various features pertaining to copper exploitation in the 19th century (Matos et al. 2003). This mine belongs to a NW-SE lineament of small vein-type copper prospects  located to the SE of the Neves Corvo mine, which includes the old mines of Barrigão, Martinlongo, Alcaria Queimada e Furnazinhas.
Geosite of Iberian dimension in the context of the IPB, with excellent access and visiting conditions.

References:
Matos, J.X., Martins, L., Rosa, C. (2003) - Parque Mineiro da Cova dos Mouros – IGM contribute for the sustainable development of the mining park. IGME, M. Geom., nº2, pp. 487-494.
Oliveira, J.T., Matos, J.X. (2004) – Geologia das regiões de Alcoutim e de Martinlongo-Vaqueiros. V Encontro de Professores de Geociências do Algarve, Vila Real de Sto. António, 15pp..
Oliveira, J.T. (1988) - Estratigrafia, sedimentologia e estrutura do Flysch da Formação de Mértola, na região de Mértola. Com. SGP, t. 74, pp. 3-19.
Oliveira, J.T; Wagner Gentis (1983) – The marine Carboniferous of South Portugal: a stratigraphic approach. Mem. Nº 29 SGP, Lisboa, pp. 3-37.

Outros valores e sua justificação

The geological trail between Martinlongo and Vaqueiros was set by LNEG in 1999, following reconnaissance of the vicinities of the nearby Cova dos Mouros mining park.

Observações

Coordenadas em actualização.