Garnet Geochemistry and Lu-Hf Geochronology of a Gold-Bearing Sillimanite-Garnet-Biotite Gneiss at the Borden Lake Belt
نویسندگان
چکیده
The Kapuskasing Structural Zone transects the Wawa and Abitibi greenstone belts in Superior province of Canadian Shield. At southern margin (KSZ), Borden Gold deposit hosts low-grade-gold mineralization within upper amphibolite- to granulite-facies sillimanite-garnet-biotite gneisses. Here, we present geochemistry Lu-Hf geochronological studies a gold-hosting garnet-bearing gneiss constrain formation history regional geological history. garnet is almandine-rich, contains inclusions quartz, biotite, pyrite, zircon. absence chemical zoning likely due intracrystalline diffusion at peak metamorphic temperatures. 176Lu-176Hf internal isochron two fractions three corresponding whole-rock splits from gneissic unit yield precise age 2629.0 ± 4.3 Ma (MSWD = 0.66), with an initial 176Hf/177Hf 0.281210 0.000010 εHfi +4.1. This signature suggests mafic source, which was derived long-term depleted reservoir, for this metasediment. consistent youngest population zircons paragneisses, were previously dated area. Our results thus provide constraints on timing retrograde upper-amphibolite metamorphism gold Borden.
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ژورنال
عنوان ژورنال: Geosciences
سال: 2022
ISSN: ['2076-3263']
DOI: https://doi.org/10.3390/geosciences12050218