Date of Award


Document Type

Open Access Master's Report

Degree Name

Master of Science in Geology (MS)

Administrative Home Department

Department of Geological and Mining Engineering and Sciences

Advisor 1

Chad Deering

Committee Member 1

Jeremy Shannon

Committee Member 2

Jim DeGraff


The Southern Complex, located near Marquette, Michigan is in the southernmost portion of the Superior Province. This complex consists of granitoids and granitic gneiss that vary in composition. In twentieth century research, Hoffman (1987) and Tinkham (1997) concluded that the Southern Complex contained two units in which the granitoid was emplaced in the granitic gneiss. Recent research conducted by Petryk (2019) determined that the Southern Complex has a U-Pb zircon age of 2600 Ma. Dalle Fratte (2020) concluded that the granitic gneiss migmatite texture was the result of a felsic magma mixing with several generations of mafic intrusions that were later deformed. Data from Petryk (2019) and Dalle Fratte (2020) were mostly from M-95, which only accounts for the western portion of the Southern Complex.

More geochemical and isotope data were collected from the eastern portion of the Southern Complex and compared with previous studies. The U-Pb zircon ages from the eastern portion of the Southern Complex were approximately 2600 Ma, similar to data from Petryk (2019) and Tinkham (1997). The eastern side also yielded some data with slight variations in geochemistry, which supports Dalle Fratte (2020) interpretation; magma mixing between a felsic melt and several generations of a more mafic melt intruding the pluton during or later in its crystallization.