Mineralogical, textural, and paragenetic studies of selected ore deposits of the Southeast Missouri lead-zinc-copper district and their genetic implications

“A detailed paragenetic study of Pb-Zn-Cu ores from the Viburnum Number 28, Brushy Creek, and Goose Creek mines in the Southeast Missouri lead district indicates a complicated paragenesis characterized by repeated periods of mineral deposition. The sequence is composed of nineteen minerals including abundant galena, sphalerite, chalcopyrite, pyrite, marcasite, dolomite, calcite, and quartz and minor siegenite, bornite, bravoite, blaubleibender covellite, covellite, gersdorffite, digenite, enargite, tennantite, dickite, and malachite. The paragenesis indicates that the ore solutions evolved in the following order: (1) Cu-rich, (2) Co-Ni-rich, (3) Pb-Zn-rich, and (4) Fe-rich. Subsequent repeated generations include cubic galena, later sphalerite, and minor crystalline chalcopyrite and other minerals which occur late in the sequence. Blaubeibender covellite is closely associated with late quartz indicating the introduction of possible supergene solutions at the end stages of mineral deposition. The general paragenetic sequence corresponds with mineral zoning and is similar throughout the entire lead district. Most importantly, the paragenetically early Cu-Co-Ni sulfides may represent a regional early development of the Cu-Co-Ni-rich mineralization similar to that in the Mine LaMotte-Fredericktown subdistrict and the southern extension of the Viburnum Trend. It is proposed that a source of Cu, Co, Ni, and some siderophile trace elements may be a series of ultramafic and mafic intrusives controlled by a fracture zone which extends north-northwest from the New Madrid rift towards Fredericktown, Missouri. This fracture zone may represent a transform fault, an epicenter trend, and a distinct, first-order lineament”--Abstract, pages xxiv-xxv