EXPLORING RARE EARTH ELEMENT CONCENTRATIONS IN THE NORTHERN COMPLEX OF MARQUETTE, MI: INSIGHTS INTO GEOCHEMICAL PATTERNS AND GEOLOGICAL SIGNIFICANCE

Rare earth elements (REE) are essential in the future of electronics, manufacturing, medical science, technology, and renewable energy, therefore, the need for further REE studies has drastically increased, and could lead to both global and local benefits as well as reveal answers to several geologic questions. The subject of this study is the Northern Complex in Marquette, MI, with an objective to perform compositional analysis via scanning electron microscopy (SEM) and x-ray fluorescence (XRF) in order to further understand the REE concentrations and characteristics of these rocks. The Northern Complex consists of volcanic and volcaniclastic rocks, Archean in age, that have been metamorphosed to greenschist and amphibolite facies. The formation being analyzed is the Compeau Creek Gneiss (CCG). A previous study of the Northern Complex done by Wilkin and Bornhorst (1991) uses REE relationships in order to answer questions regarding magmatic evolution and does not focus on the potential for REE resources, but concluded that several rocks within the Northern Complex contained noticeable amounts of REE mineralization in the minerals zircon, monazite, and apatite. SEM analysis reflects the prevalence of zircons and therefore they are the focal point of this study which will further analyze the rocks of the Northern Complex, in relation to the severe lack of recent studies in this area. Observation of the CCG using SEM analysis identified the presence of the REEs cerium, lanthanum as well as other transition metals such as platinum, lead, titanium, and vanadium. The mineralization of these particular elements each have a specific set of implications regarding either their original inclusion within the CCG or their secondary substitution; this study will dive into characterizing each element's connotation in the CCG’s history. This study stands on a premise that the REE potential of rocks in the Northern Complex can be understood further by using XRF and SEM to characterize REE concentrations within zircons. In addition, this study aims to draw relationships between geological environments and REE substitution within zircons, as well as gaining insight on the mechanisms and trends of REE mineralization.