Medas (Portugal)
Dúrico-Beirã region, Valongo anticline (northern Portugal), Portugal
Other hydrothermalSb-Au
- Type
- Sb-Au quartz veins
Sb-Au quartz veins of the Dúrico-Beirã region (Central Iberian zone), on the flanks of the Variscan Valongo anticline, in the Cambrian schist-greywacke complex and Ordovician metasediments; 63 recorded antimony areas. Aqueous-carbonic fluids at 340 to 290 °C then aqueous fluids at 225 to 128 °C during the berthierite and stibnite stage (Couto et al., 1990). Stibnite lead (Neiva et al., 2008) close to the orogene curve, µ2 of 9.66 to 10.04: homogeneous upper-crustal source, probably the host metasediments. Coordinates not published (map only).
206Pb/204Pb isotope ratio, no unit Values of the same system
Standard : NIST SRM 981
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 18.399 | 1 | stibnite Single analysis; sample Medas; µ2 = 10.04 (Stacey and Kramers). | Neiva et al. (2008), Antimony quartz and antimony-gold quartz veins from northern Portuga… |
207Pb/204Pb isotope ratio, no unit Values of the same system
Standard : NIST SRM 981
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 15.681 | 1 | stibnite Single analysis; sample Medas; µ2 = 10.04 (Stacey and Kramers). | Neiva et al. (2008), Antimony quartz and antimony-gold quartz veins from northern Portuga… |
208Pb/204Pb isotope ratio, no unit Values of the same system
Standard : NIST SRM 981
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 38.539 | 1 | stibnite Single analysis; sample Medas; µ2 = 10.04 (Stacey and Kramers). | Neiva et al. (2008), Antimony quartz and antimony-gold quartz veins from northern Portuga… |
Deposits of the same type
Cite this page
IsoFind Atlas (2026). Medas (Portugal), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/medas-portugal/ (accessed 2026-10-16).
@misc{isofind2026medasportugalisotopesignature,
title = {Medas (Portugal), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/medas-portugal/},
note = {Accessed 2026-10-16}
}Updated : 2026-10-16