The lead-zinc and associated ores of La Union, Sierra de Cartagena, Spain

Abstract

The Pb-Zn-Fe ores of La Union, Spain, occur in an area of about 50 square km in three facial types of parageneses: (1) sulfides-carbonates-silica, (2) sulfides-carbonates-silica-greenalite-magnetite, and (3) oxides-hydroxides-sulfates-carbonates-silica. The distribution of the ore deposits shows a central zone with paragen.es.es (3) and (1) in direct association with late-Tertiary subvolcanic rocks and breccia pipes, an intermediate zone characterized mainly by paragenesis (2), and an outward zone characterized mainly by paragenesis (1). The occurrence of paragenesis (3) in the three zones at higher levels than parageneses (2) and (1) suggests a vertical zoning. A goochemical zoning with, from the central zone outward, Sn, Cu, Be, and Ba richer zones is also apparent. Mineralogical data indicate formation temperatures largely below 250øC and, within range of probable values of rs2 and fc•2, an increasing importance of fo2 toward the central and higher zones. The absence of crosscutting relations between deposits of different paragenetic type suggests a monascendant or facial zoning related to a center of Late Tertiary subvolcanic rocks and superimposed on the pre-Pliocene geology of the region. The ore deposits are syngenetic fissure veins in Late Tertiary volcanic rocks and epigenetic veins and peneconcordant replacement orebodies in older formations. Geological relations and the structure of the ore deposits indicate strong structural and lithological controls and shallow depths of formation within the zone of ground-water movement. o / a_ / // J z z

Geochemical characterisation of surface waters, topsoils and efflorescences in a historic metal-mining area in Spain

“…The ore deposits in Sierra Minera have iron, lead and zinc as the main metal components (Oen et al 1975) and appeared as massive strata-bound (locally named Bmantos^). Two types of mineralogical association are observed in the mantos: (1) greenalite-magnetite-siderite-sulphide-silica and (2) sulphidesiderite-silica.…”

Cadmium, copper, lead, and zinc in secondary sulfate minerals in soils of mined areas in Southeast Spain

“…The remnants and tailings from extraction and processing of ores consisting of galena, sphalerite, and pyrite (Oen et al, 1975;Departamento de Ciencias Sociales del I. E. S. Sierra Minera, 2008) lead to the formation of a low pH and high contents of soluble metals. Low pH in soils was due to the oxidation of pyritic minerals (e.g., pyrite and marcasite) through the following reactions:…”

Scientific, Educational, and Environmental Considerations Regarding Mine Sites and Geoheritage: A Perspective from SE Spain

“…The association of greenalite magnetite with Pb Zn ores in the manto-type ore deposits from Cartagena-La Union (Fig. 6a) constitutes a most unusual case unknO\vn anywhere else (Oen et al 1975). Besides, melallogenic clusters (groups of genetically related ore deposits) are usually very simple, containing a single or two (at the most) ore deposit types.…”