Characterization of placer gold deposits from central Portugal: preliminary results

The streams in the Lower Tagus Basin and along the contact of the Central Iberian and Ossa Morena zones in central Portugal carry significant amounts of gold. In this study, four placer gold deposits have been characterized using geochemical, morphological and heavy mineral data and compared with the styles of gold mineralization in the vicinity. The geochemical similarities of the Tagus palaeo-placer and the Tripeiro and Erges gold placers suggest a primary gold source likely to be similar to the mineralization found at Sarzedas and Pomar. The more heterogenic composition of the Caia gold placer probably reflects the different styles of mineralization found at La Codosera, Los Algarbes and Alburquerque to the east.