RT Journal Article
T1 Variability in fluid sources in the fluorite deposits from Asturias (N Spain): Furtherevidences from REE, radiogenic (Sr, Sm, Nd) and stable (S, C, O) isotope data
A1 Sánchez Pérez-Cejuela, Virginia
A1 Cardellach, Esteve
A1 Corbella, Mercè
A1 Vindel Catena, Elena
A1 Martín Crespo, Tomás
A1 Boyce, Adrian J.
AB Fluorite deposits in Asturias (Iberian Peninsula, N Spain) are hosted in Permo-Triassic and Paleozoic rocks.The three main districts of Berbes, La Collada and Villabona preferentially occur along the margins of aMesozoic basin and comprise veins and stratabound mineralization composed of fluorite, barite, calcite,dolomite, quartz and sulphides. Although the geological framework is similar and fluorite dominates in alldeposits, variability in sources and processes has led to each area having its own distinctive characteristics. Srisotope data of fluorite, calcite and barite (87Sr/86Sr=0.7080 to 0.7105) are compatible with a mixingbetween seawater and an evolved groundwater that interacted with basement rocks. Sm/Nd ratios influorites from Villabona district provide an isochron age of 185±28 Ma (Late Triassic–Late Jurassic),consistent with other hydrothermal events in the Iberian Peninsula and Europe. The total REE content offluorite increases from Berbes to Villabona by an order of magnitude (0.4 to 9.3). The La/Lu ratio in fluoritesdecreases from a mean value of 0.36 in Berbes, 0.17 in La Collada to 0.09 in Villabona indicating a strongfractionation between LREE and HREE.Calculated δ18O of fluids ranges from 0.3 to +7.4‰ during barite precipitation, from +0.8 to +4‰ duringquartz formation and around +3‰ during carbonate deposition. The δ34S of barite (+17 to +56‰), isexplained by sulphate reduction processes (either thermochemically or bacterially mediated) in a systemclosed with respect to sulphate. The δ34S of sulphide (+0.6 to −32‰) is compatible with these processesalthough bacterial processes must have dominated at Villabona. Organic matter was an important source of Cin the fluids especially in Villabona (δ13C=−14.8 to −2.5‰ in calcites and from −7.9 to −2.2‰ indolomites). Differences in host rock and position within the basin, and the lithology of the basement, seem tohave exerted a strong control on the chemistry of mineralizing fluids providing each district with distinctivecharacteristics.
PB Elsevier Science B.V., Amsterdam
SN 0169-1368
YR 2010
FD 2010
LK https://hdl.handle.net/20.500.14352/42283
UL https://hdl.handle.net/20.500.14352/42283
LA eng
DS Docta Complutense
RD 30 dic 2025