A fluid inclusion and light element stable isotope study of the gold-bearing quartz vein system, Falun, Sweden

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Authors:Aberg, A.; Fallick, A. E.
Author Affiliations:Primary:
Geological Survey of Sweden, Mala, Sweden
Other:
Scottish Universities Research and Reactor Center, United Kingdom
Volume Title:Mineralium Deposita
Source:Mineralium Deposita, 28(5), p.324-333. Publisher: Springer-Verlag, Berlin, Federal Republic of Germany. ISSN: 0026-4598
Publication Date:1993
Note:In English. 43 refs.; illus., incl. geol. sketch map, 3 tables, sect.
Summary:This mineralization lies approx 230 km NW of Stockholm within the early Proterozoic volcano-sedimentary sequence of Bergslagen. It consists of a system with subparallel quartz veins that cross cut the alteration zone of the Falun massive sulphide deposit. Early barren and late Au-bearing quartz veins follow tectonic structures postdating the formation of the massive sulphide ores. Both generations of veins are epigenetic to the massive sulphide ore and were formed by hydrothermal processes. Fluid inclusions study of the Au-bearing quartz veins indicates a low-moderately saline fluid (0.3-17.4 wt.% eq. NaCl). Heterogeneous trapping is indicated by coexisting inclusions showing a variable CO2 content from 100% CO2 +- CH4 to 100% aqueous fluid. Total homogenization T also show a wide spread of 116-350 degrees C with a slightly bimodal distribution with peaks at approx 180 and 280 degrees C. Measured delta D values of -69 to -63 per mille (SMOW) of inclusion fluid and calculated delta18O values of hydrothermal fluids of -7.5 to -1.4 per mille (SMOW) strongly suggest a meteoric origin for the fluids. The quite consistent delta D values and the range of delta 18O values indicate that major water-rock interaction led to the evolution of delta 18O of the hydrothermal fluids. [R.E.S.]
Subjects:D/H; Dikes; Fluid inclusions; Geochemistry; Gold ores; Hydrogen; Inclusions; Intrusions; Isotope ratios; Isotopes; Metal ores; Mineral deposits, genesis; O-18/O-16; Oxygen; Precambrian; Proterozoic; Quartz veins; Sedimentary rocks; Stable isotopes; Tectonics; Upper Precambrian; Veins; Volcanic features; Bergslagen; Europe; Scandinavia; Sweden; Western Europe; Falun Mine
Abstract Numbers:94M/4414
Record ID:1997031762
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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