Aluminium-iron phosphate mineralization at Gava (Catalonia): typology [Mineralizaciones de fosfatos ferrico-aluminicos de Gava (Catalunya): tipologia]
Por:
Camprubi A., Costa F., Melgarejo J.C.
Publicada:
1 ene 1994
Resumen:
The three main types of Al-Fe phosphate mineralization in the Catalonian Coastal Ranges are well exposed in the Gava-Bruguers area: stratiform, veins of several generations, and limestone replacement. Stratiform phosphates (apatite, variscite, strengite, phosphosiderite) are hosted by Al-shales (Llandoverian). A sedimentary-exhalative origin is suggested for them. Phosphate veins are hosted by Al-shales as well. The Silurian-Devonian limestones were ankeritized, then replaced by iron hydroxides. There are occurrences of porosity-filling tinticite in vugs or veins and as nodules in irregular bodies. Tinticite was early formed and it is being replaced by calcioferrite. Late Ca-bearing phosphate veins crosscut the ensemble. These epigenetic phosphates were produced by acidic and oxydizing fluids due to leaching of sulfides from the Silurian series. Hence, the chemistry of the mineral association is derived from that of the host rocks. -from English summary
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