Hydrothermalismes anté-Hercynien en Sud-Ibérie : apport de la géochimie isotopique du plomb.

Eric Marcoux (1) , Emilio Pascual (2) , Jérôme Onézime (1)

1 ISTO - Institut des Sciences de la Terre d'Orléans
2 Université d'Huelva, Departamento de Geologia y Mineria

Lead isotope study has been performed on massive sulphide deposits of Ossa-Morena and Aracena Belt (South Iberia). Results suggest the existence of at least two ancient hydrothermal events. The first one, Upper Brioverian in age (not, vert, similar600-570 Ma), gave birth to Maria-Luisa and Puebla de la Reina massive sulphide deposits; it thus confirms the existence of a Cadomian orogen in South Iberia. Isotopic compositions indicate a local contribution of mantle-derived material (Maria Luisa mine), confirming the presence of ancient oceanic crust in Aracena Belt. This mineralising event seems to extend till the Armorican Massif. The second episode, Eo-Hercynian in age (not, vert, similar400-350 Ma) has allowed genesis of massive sulphide deposits of la Nava Paredon and Aguas Blancas, and could be coeval with the emplacement of South-Iberian massive sulphide ore deposits in the neighbouring South-Portuguese Zone. A more continental crustal source for later ore deposits could explain the much more important metal accumulation in this zone.

Keywords: lead isotope; Brioverian; massive sulphide deposits; South Iberia

Domains: Geochemistry; Global Changes

Eric Marcoux, Emilio Pascual, Jérôme Onézime. Hydrothermalismes anté-Hercynien en Sud-Ibérie : apport de la géochimie isotopique du plomb.. Comptes Rendus Géoscience, 2002, 334, pp.259-265. ⟨10.1016/S1631-0713(02)01734-0⟩. ⟨hal-00072651⟩