Figure 6

(a.) Hand specimen photo of North Ore Shoot specular hematite-chalcopyrite ore (DDH 363A 3215 ft.). Note the rhythmic specular hematite // pyrite-chalcopyrite layering. This is the result of both mineralogical and grain size variations. Rhythmic layering also locally shows hematite blades growing perpendicular to layers. Einaudi (pers. comm., 1997) interprets this texture to represent direct replacement of carbonate rock by massive ore. The non-opaque gangue is talc (+ trace quartz).

(b.) Hand specimen photo of rhythmic specular hematite // chalcopyrite-(pyrite) layering in ore from the C-bed orebody, Superior, Arizona (3833 level). Layering like this is common near contacts between massive sulfide and hematite-bearing ores. Layering defined by grain size variations of hematite with local chalcopyrite bands is typical of massive hematite-carbonate contacts.
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