Fluid Properties In the Formation of High-Grade Iron Ore in Northern Minnesota

The Mesabi Iron Range in Northern Minnesota has been a major producer of iron ore for over 100 years. Most of the known high-grade ore lies near the surface and has been already been mined. Determining whether more high-grade ore may lie at depth could have significant economic impact on the mining industry in northern Minnesota. To evaluate the likelihood of finding more high-grade iron ore deeper underground, it is important to determine the source of the fluids that are responsible for that ore. I have been examining Morey\u27s hypothesis in which he proposed that a plate collision event 1.8 billion years ago drove deep fluids upward along faults within the iron formation. In this case, high-grade ore could exist deeper within the iron formation, which is tilted gently beneath the surface. Samples collected in the iron range have been analyzed using various geologic methods. Growth banding, using cathodoluminescence, and the salinity of the fluid from fluid inclusions were used to evaluate the source of the fluid