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Cathodoluminescence As A Means For Distinguishing Hydrothermal From Pre-Hydrothermal Quartz In Sulfide-Bearing Mineral Deposits On The Northern Fringe Of The Upper Mississippi Valley Zinc-Lead District, Ne Iowa And Sw Wisconsin, Paul L. Garvin

Journal of the Iowa Academy of Science: JIAS

Sulfide-bearing mineral deposits, located on the northern fringe of the Upper Mississippi Valley Zinc-Lead District, are contained in early Ordovician carbonate rocks that are extensively silicified and dolomitized. Some silica and dolomite appear to be products of the hydrothermal processes that also formed fracture-filling and cavity-lining sulfides and other cogenetic minerals; other silica and dolomite appear to result from low-temperature, pre-hydrothermal regional diagenesis. Distinguishing hydrothermal quartz (jasperoid) from pre-hydrothermal quartz (chert) solely by hand specimen and thin section petrography is difficult because these two types of mineralization are often intimately associated with each other. Polished slabs from several of these …