RT Journal Article
T1 Sources and composition of fluids associated with fluoritedeposits of Asturias (N Spain)
A1 Sánchez Pérez-Cejuela, Virginia
A1 Vindel Catena, Elena
A1 Martín Crespo, Tomás
A1 Corbella, Mercè
A1 Cardellach, Esteve
A1 Banks, David
AB The fluorite deposits of Asturias (northern Iberian Peninsula) are hosted by rocks of Permo-Triassic and Palaeozoicage. Fluid inclusions in ore and gangue minerals show homogenization temperatures from 80 to 170C and thepresence of two types of fluids: an H2O–NaCl low-salinity fluid (<8 eq. wt% NaCl) and an H2O–NaCl–CaCl2 fluid(7–13 wt% NaCl and 11–14 wt% CaCl2). The low salinity and the Cl ⁄ Br and Na ⁄ Br ratios (Cl ⁄ Brmolar 100–700and Na ⁄ Brmolar 20–700) are consistent with an evaporated sea water origin of this fluid. The other end-memberof the mixture was highly saline brine with high Cl ⁄ Br and Na ⁄ Br ratios (Cl ⁄ Brmolar 700–13 000 and Na ⁄ Brmolar700–11 000) generated after dissolution of Triassic age evaporites. LA-ICP-MS analyses of fluid inclusions in fluoritereveal higher Zn, Pb and Ba contents in the high-salinity fluids (160–500, 90–170, 320–480 p.p.m. respectively)than in the low-salinity fluid (75–230, 25–150 and 100–300 p.p.m. respectively). The metal content of thefluids appears to decrease from E to W, from Berbes to La Collada and to Villabona. The source of F is probablyrelated to leaching of volcanic rocks of Permian age. Brines circulated along faults into the Palaeozoic basement.Evaporated sea water was present in permeable rocks and faults along or above the unconformity between thePermo-Triassic sediments and the Palaeozoic basement. Mineralization formed when the deep brines mixed withthe surficial fluids in carbonates, breccias and fractures resulting in the formation of veins and stratabound bodiesof fluorite, barite, calcite, dolomite and quartz and minor amounts of sulphides. Fluid movement and mineralizationoccurred between Late Triassic and Late Jurassic times, probably associated with rifting events related to theopening of the Atlantic Ocean. This model is also consistent with the geodynamic setting of other fluorite-richdistricts in Europe.
PB Blackwell Publishing
SN 1468-8115
YR 2009
FD 2009
LK https://hdl.handle.net/20.500.14352/50111
UL https://hdl.handle.net/20.500.14352/50111
LA eng
DS Docta Complutense
RD 6 abr 2025