Sulfide assemblages are concentrated in persistent bands differing from one another in mineral composition and crystal habit. The bands are mostly concordant with bedding and are believed to reflect precipitation of sulfides during sedimentary accumulation. The style of deformation of individual layers is dependent, in part, on the band of sulfide present, and sulfide texture is related to position in folds and shears; both phenomena indicate that the sulfides antedate the deformation. Theoretical analyses of pertinent processes of precipitation and plastic deformation of sulfides are inconclusive because of the large number of uncertainties. Sulfur isotope data suggest that sulfur is biogenic.

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