TY - JOUR
T1 - Mineralogy and geochemistry of tin- and germanium-bearing copper ore, Barrigão re-mobilized vein deposit, Iberian Pyrite Belt, Portugal
AU - Reiser, Fiona K.M.
AU - Rosa, Diogo R.N.
AU - Pinto, Álvaro M.M.
AU - Carvalho, João R.S.
AU - Matos, João X.
AU - Guimarães, Fernanda M.G.
AU - Alves, Luis C.
AU - de Oliveira, Daniel P.S.
N1 - Funding Information:
The main author would like to thank Professor Dr Jochen Schlüter (University of Hamburg) for the acquisition of a germanite sample. This work was financially supported by the Portuguese Foundation for Science and Technology (FCT-MCTES) through project PTDC/CTE-GIN/67027/2006 (INCA Project).
PY - 2011/8/20
Y1 - 2011/8/20
N2 - The Barrigão re-mobilized copper vein deposit*Iberian Pyrite Belt*southern Portugal, is located about 60 km south of Beja and 10 km southeast of the Neves Corvo ore deposit, in Alentejo Province. The deposit is structurally associated with a NE-SW striking fault zone inferred to have developed during late Variscan deformation. The copper ore itself is a breccia-type ore, characterized by up to four ore-forming stages, with the late stages showing evidence of fluid-driven element re-mobilization. The ore is dominated by chalcopyrite + tennantite-tetrahedrite, with minor arsenopyrite, pyrite, and lollingite. The supergene paragenesis is composed mainly of bornite, covellite, and digenite. Whole-rock analyses show anomalous tin and germanium contents, with averages of 320 and 61 ppm, respectively. Electron microprobe analysis of Barrigao ores revealed the germanium and tin to be restricted to chalcopyrite, which underwent late-stage hydrothermal fluid overprint along distinct vein-like zones. The measured zonal enrichment of tin and germanium is related to limited element re-mobilization associated with mineral replacement, which resulted in distinctive mineral disequilibrium. Fluid-driven element zoning affected chalcopyrite and tennantite coevally. The average contents of germanium and tin in chalcopyrite are of 0.19 and 0.55 wt.%, respectively, as confirmed through additional micro-proton-induced X-ray emission (micro-PIXE) analysis. The distribution of tin and germanium in chalcopyrite correlates strongly with iron. Tin and germanium covary. Minute sub-microscopic inclusions of an unknown Cu-Sn-Ge sulphide phase have been detected in chalcopyrite and in small vugs therein. These inclusions hint at a stanniferous sulphide as the most possible host for tin and germanium in chalcopyrite, although the idea of limited incorporation of these two elements through element substitution cannot be completely excluded.
AB - The Barrigão re-mobilized copper vein deposit*Iberian Pyrite Belt*southern Portugal, is located about 60 km south of Beja and 10 km southeast of the Neves Corvo ore deposit, in Alentejo Province. The deposit is structurally associated with a NE-SW striking fault zone inferred to have developed during late Variscan deformation. The copper ore itself is a breccia-type ore, characterized by up to four ore-forming stages, with the late stages showing evidence of fluid-driven element re-mobilization. The ore is dominated by chalcopyrite + tennantite-tetrahedrite, with minor arsenopyrite, pyrite, and lollingite. The supergene paragenesis is composed mainly of bornite, covellite, and digenite. Whole-rock analyses show anomalous tin and germanium contents, with averages of 320 and 61 ppm, respectively. Electron microprobe analysis of Barrigao ores revealed the germanium and tin to be restricted to chalcopyrite, which underwent late-stage hydrothermal fluid overprint along distinct vein-like zones. The measured zonal enrichment of tin and germanium is related to limited element re-mobilization associated with mineral replacement, which resulted in distinctive mineral disequilibrium. Fluid-driven element zoning affected chalcopyrite and tennantite coevally. The average contents of germanium and tin in chalcopyrite are of 0.19 and 0.55 wt.%, respectively, as confirmed through additional micro-proton-induced X-ray emission (micro-PIXE) analysis. The distribution of tin and germanium in chalcopyrite correlates strongly with iron. Tin and germanium covary. Minute sub-microscopic inclusions of an unknown Cu-Sn-Ge sulphide phase have been detected in chalcopyrite and in small vugs therein. These inclusions hint at a stanniferous sulphide as the most possible host for tin and germanium in chalcopyrite, although the idea of limited incorporation of these two elements through element substitution cannot be completely excluded.
KW - Barrigao ore deposit
KW - chalcopyrite
KW - germanium
KW - high-technology elements
KW - Iberian Pyrite Belt
KW - tin
UR - http://www.scopus.com/inward/record.url?scp=79957521274&partnerID=8YFLogxK
U2 - 10.1080/00206811003683168
DO - 10.1080/00206811003683168
M3 - Article
AN - SCOPUS:79957521274
SN - 0020-6814
VL - 53
SP - 1212
EP - 1238
JO - International Geology Review
JF - International Geology Review
IS - 10
ER -