justificação do valor científico
At Praia do Belixe, vertical cliffs display an approximately 0.5 km outcrop of Carixian age (Lower Jurassic) fine grained dolomitic limestone containing chert beds, nodules and dikes, overlain by marly limestones, these two packages are separated by an unconformity. The beds are cross cut by normal faults and joints, some of which were, at some stage, injected with calci-clastic sands, which were later percolated by silica-rich fluids. These fluids originated stratified cherts and quartz and chalcedony veins within the tensile joints and hydrothermal quartz along the extensional faults (Ribeiro et al., 2004, Ribeiro, 2005). Syn-sedimentar extensional faults and unconformities are well exposed, as well as, a syn-sedimentar compressional episode that occurred during the Carixian, which was responsible to boudinage of the chert dikes (Terrinha et al., 2002). Of particular interest are the fluid injection dikes and nodules, the epigenetic precipitation of quartz and the later dolomitisation that precede the Domerian carbonates sedimentation. The exceptional outcrop conditions and striking contrast of the limestone, dolostones, cherts and quartz allow identification of different tectonic, diagenetic and hydrothermal processes, which all occurred during the Carixian.
RIBEIRO, C. Evolução diagenética e tectonosedimentar do Carixiano da Zona de Sagres, Bacia Algarvia, Portugal. PhD thesis, submitted. Universidade de Évora, Portugal. 2005.
RIBEIRO, C, TERRINHA, P., OUAJHAIN, B. AZEVEDO, M. R. (2004) - Silicification and Dolomitization of a Carbonate Tethysian Carixian Basin, Algarve, South Portugal. Eustasy and Tectonics. 23rd meeting of the International Association of Sedimentologists, 15th-17th September, 2004, Coimbra, Portugal.
TERRINHA, P., RIBEIRO, C., KULLBERG, J. C., ROCHA, R.; RIBEIRO, A. (2002). Compression episodes during rifting and faunal isolation in the Algarve Basins, SW Iberia. Journal of Geology, 110: 101 - 113.