For my research project, I analyzed lake sediment cores from Deming Lake, a small, kettle lake located in Itasca State Park. The goal was to reconstruct the history of lake-level change at Deming during the last 800 years. I took samples at one to two-centimeter intervals from 3 cores (one deep-water core, one near-shore, and one mid-depth) and conducted two different types of analysis. First, I measured susceptibility, anhysteretic remanent magnetization (ARM), and isothermal remanent magnetization (IRM). Next, I used a method called Loss-on-Ignition to measure the amount of organic material, carbonate, and silicate material in the samples. These analyses were intended to reveal relative facies changes within the cores over time, thus indicating lake-level changes.
While I found no evidence of lake-level change within the past 800 years, I did find a region of significant change in lithology and composition within the cores. This section seems to correspond with the Mid-Holocene dry period, and we attribute the patterns observed to a change in lake level or lake clarity due to increased aridity. I also found that the magnetic analysis does not produce clearly meaningful data at this lake, possibly due to dissolution or diagenesis. I suggest that future studies involve other types of analysis and focus on the more shallow region of the lake where subtle lake-level changes might be recorded.