Origin of the mineralizing fluids from the Carboniferous sedex deposits of L'Alforja (SW Catalonian Coastal Ranges, Spain)
Por:
Canet C., Alfonso P., Melgarejo J.C., Fallick A.E.
Publicada:
1 ene 2003
Resumen:
Fluid inclusions were studied in stratiform ore deposits hosted in Namurian sedimentary series near L'Alforja (southernmost part of the Catalonian Coastal Ranges, NE Spain). Primary fluid inclusions in quartz crystals from L'Alforja ore bodies are two-phase (L-V), with salinity between 1.1 and 18.0 wt.% NaCl eq. and homogenization temperature mainly in the range of 220-260°C. ?D values analyzed in chlorite range between - 63‰ and -33‰, and ?18O values range between +2.7‰ and + 6.8‰ in chlorite, and from +8.6‰ to +10.7‰ in quartz. Fluid inclusions and oxygen-hydrogen stable isotopes indicate that the mineralizing fluid of L'Alforja was mainly seawater. The hydrothermal fluid had lower density than seawater, so producing buoyant plumes on debouching at the seafloor, and the metals precipitated with the decrease of temperature. Hydrothermal fluids related to late-Hercynian porphyritic granite dykes produced local recrystallization of the ores, as well as a younger generation of high saline fluid inclusions, and locally caused isotopic reequilibration. © 2003 Elsevier Science B.V. All rights reserved.
Filiaciones:
Departament de Cristallografia i Mineralogia i Dipòsits Minerals (Universitat de Barcelona), c. Marti i Franques s/n., 08028 Barcelona, Spain
Institute de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Del. Coyoacan, 04510 Mexico, D.F., Mexico
Isotope Geosciences Unit, SUERC, East Kilbride, Glasgow G75 0QF, United Kingdom
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