Quartz-carbonate lodes have produced a major part of the world's gold. The source for the lodes, which were emplaced along shear zones in the upper crust, has been enigmatic. The Bamble belt of south Norway is depleted in gold by more than an order of magnitude relative to its crustal abundance; other elements present in gold deposits have also been lost. Gold dissolved and was removed in oxidized, sulfur-rich fluids rising through this broad ductile shear zone during high-grade metamorphism. Deformation, synchronous with metamorphism, created the permeability that permitted a pervasive flow of fluids.

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