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Petrogenesis Of The Eagle East Gabbro In Marquette County, Mi, Usa, Kevin Rupp

Masters Theses

The Eagle East gabbroic intrusion in Michigan’s Upper Peninsula, is a subvertical pluglike intrusion found near the base of the Eagle East Ni-Cu-PGE deposit. U-Pb baddeleyite dating of the gabbro yields an age of 1103.4 ± 1.2 Ma, suggesting formation during the early stages of the Midcontinent Rift System (MRS). Drill core observations show that the intrusion cross-cuts the eastern most portion of the Eagle East ultramafic conduit. The internal portion of the intrusion is made up of two main rock types, gabbro and gabbro norite, which consist of plagioclase (50-60%), clinopyroxene (15-25%), orthopyroxene (0-15%), olivine (0-10%), and are generally …