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Distribution And Variability In Sulfur Isotopes Within Paleoproterozoic Metasedimentary Strata Of The Michigamme Formation, Upper Peninsula, Michigan, Beau J. Haag

Masters Theses

In the Upper Peninsula of Michigan, the Paleoproterozoic Michigamme Formation is composed of a thick package of metasedimentary rocks derived from foreland basin sediments which were deposited during the 1.8Ga Penokean Orogeny. These rocks contain significant, but variable amounts of texturally distinct sulfide minerals such as pyrrhotite and pyrite. We report a systematic relationship between δ³⁴S values from sulfide mineral occurrences, and their stratigraphic locations regardless of texture and mineral composition. We suggest the sulfide minerals within the Michigamme Formation have inherited δ³⁴S values from early sedimentarydiagenetic sulfides, therefore preserving primary isotopic signatures. The observed stratigraphic …

Geochemical And Petrological Studies On The Origin Of Nickel-Copper Sulfide Mineralization At The Eagle Lntrusion In Marquette County, Michigan, Benjamin Davis Hinks

Masters Theses

The Eagle magmatic intrusion is located in the Upper Peninsula of Michigan in Marquette County. It hosts a high grade magmatic nickel-copper sulfide ore deposit. Country rocks surrounding the Eagle intrusion are metamorphosed slate and greywacke of the Proterozoic Michigamme Formation and Archean granite-gneiss. The aim of this thesis is to characterize the magmatic sulfide mineral deposit at Eagle and to establish its relationship to the surrounding host rocks of the Baraga Basin area.

The Eagle East intrusion is located 600 meters east of the Eagle intrusion. These two intrusions are similar in composition and sulfide mineralization. Sulfide textural domains …