OLIVINE VARIABILITY FROM THE NICKEL LAKE MACRODIKE IN NORTHERN MINNESOTA

This project is looking at the mineralogy of olivine crystals found in an igneous feature called the Nickel Lake Macrodike. This geologic setting is part of the 1.1 Ga Midcontinent Rift System that extends from Kansas to Michigan. The Nickel Lake Macrodike is found in northern Minnesota near the town of Ely and northwest of the Duluth Complex. Olivine crystals are typically only found in ultramafic and mafic rocks which are associated with the Earth’s mantle. This project seeks to build upon the area’s extensive bedrock and structural geologic mapping (Peterson et al., 2006-2008). Our research is characterizing the mineralogical composition of the magma that were capable of olivine crystallization. These geochemical data may provide information regarding the magma's nature and facilitate insight into areas geologic history and mining potential. Since the geology of the Duluth Complex and associated Nickel Lake Macrodike are diverse, our hypothesis is that the mineralogy of the olivine crystals will reflect proximity to the rift’s center. Raic et al., 2018, identified evidence of fluid inclusions in a similar Bathtub Intrusion a few miles to the southwest of our study area. We are interested in documenting if similar fluid includes are present near the Nickel Lake Macrodike. Data collection and interpretation is a focus for this undergraduate research project. Since data is being referenced from Peterson et al. in addition to samples collected from the field to be brought back for lab analysis.