The sources and evolution of mineralising fluids in iron oxide–copper–gold 
systems, Norrbotten, Sweden: Constraints from Br/Cl ratios and stable Cl 
isotopes of fluid inclusion leachates

Gleeson, S. A.; Smith, M. P.

doi:10.1016/j.gca.2009.06.005

Datensatz

DATENSATZ AKTIONENEXPORT

Zur Ablage hinzufügen

Lokale TagsFreigabegeschichteDetailsÜbersicht

Freigegeben

Zeitschriftenartikel

The sources and evolution of mineralising fluids in iron oxide–copper–gold systems, Norrbotten, Sweden: Constraints from Br/Cl ratios and stable Cl isotopes of fluid inclusion leachates

Urheber*innen

/persons/resource/sgleeson

Gleeson, S. A.
0 Pre-GFZ, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum;

Smith, M. P.
External Organizations;

Externe Ressourcen

Es sind keine externen Ressourcen hinterlegt

Volltexte (frei zugänglich)

Es sind keine frei zugänglichen Volltexte in GFZpublic verfügbar

Ergänzendes Material (frei zugänglich)

Es sind keine frei zugänglichen Ergänzenden Materialien verfügbar

Zitation

Gleeson, S. A., Smith, M. P. (2009): The sources and evolution of mineralising fluids in iron oxide–copper–gold systems, Norrbotten, Sweden: Constraints from Br/Cl ratios and stable Cl isotopes of fluid inclusion leachates. - Geochimica et Cosmochimica Acta, 73, 19, 5658-5672.
https://doi.org/10.1016/j.gca.2009.06.005

Zitierlink: https://gfzpublic.gfz-potsdam.de/pubman/item/item_1941910

Zusammenfassung

We have analysed the halogen concentrations and chlorine stable isotope composition of fluid inclusion leachates from three spatially associated Fe-oxide +/- Cu +/- Au mineralising systems in Norrbotten, Sweden. Fluid inclusions in late-stage veins in Fe-oxide-apatite deposits contain saline brines and have a wide range of Br/Cl molar ratios, from 0.2 to 1.1 x 10(-3) and delta(37)Cl values from -3.1 parts per thousand to -1.0 parts per thousand. Leachates from saline fluid inclusions from the Greenstone and Porphyry hosted Cu-Au prospects have Br/Cl ratios that range from 0.2 to 0.5 x 10(-3) and delta(37)Cl values from -5.6 parts per thousand to -1.3 parts per thousand. Finally, the Cu-Au deposits hosted by the Nautanen Deformation Zone (NDZ) have Br/Cl molar ratios from 0.4 to 1.1 x 10(-3) and delta(37)Cl values that range from -2.4 parts per thousand to +0.5 parts per thousand, although the bulk of the data fall within 0 parts per thousand +/- 0.5 parts per thousand. The Br/Cl ratios of leachates are consistent with the derivation of salinity from magmatic sources or from the dissolution of halite. Most of the isotopic data from the Fe-oxide-apatite and Greenstone deposits are consistent with a mantle derived source of the chlorine, with the exception of the four samples with the most negative values. The origin of the low delta(37)Cl values in these samples is unknown but we suggest that there may have been some modi. cation of the Cl-isotope signature due to fractionation between the mineralising fluids and Cl-rich silicate assemblages found in the alteration haloes around the deposits. If such a process has occurred then a modified crustal source of the chlorine for all the samples cannot be ruled out although the amount of fractionation necessary to generate the low delta(37)Cl values would be significantly larger. The source of Cl in the NDZ deposits has a crustal signature, which suggests the Cl in this system may be derived from (meta-) evaporites or from input from crustal melts such as granitic pegmatites of the Lina Suite. (C) 2009 Elsevier Ltd. All rights reserved.