69-9 Sediment Characterization of a Seven Meter Loess Section in Northwestern Missouri, USA and the Implications for Paleoclimate and Sediment Transport

Session: Joint SGD-SEPM-IAS Focus on the Sedimentary Record of Climate Change (Posters)

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Abstract:

Loess is one of the most widespread surficial deposits in the continental US, particularly along major rivers draining glaciated areas, including the Missouri River basin. As Quaternary glacial ice sheets advanced, exposed rock was repeatedly eroded into silt and clay-sized grains. These fine-grained proglacial sediments were mobilized by wind. The study site is located along the north embankment of Highway 210, just north of Kansas City and the Missouri River. Samples from a vertical section atop a constructed roadcut bench within the loess deposit came from AR210-A2 (two meters) and AR210-B (five meters) for a total of seven meters. A range of analyses characterizes the sediment's components, particle size, mineral composition, and elemental composition. Loss-On-Ignition (LOI) determined moisture content, mineral abundance, and percentage of carbonate. AR210-A2, the average for the two meters for moisture was 4.07%, organics was 0.76%, carbonate was 1.19% and the mineral content was 93.3%. AR210-B, the five meters averaged 2.82% for moisture, 1.67% for organics, 1.05% for carbonate, and 94.4% for mineral content. Particle size graphs are negatively skewed.  Each sample displayed a consistent pattern of silt-sized particles between 0.03 mm and 0.1 mm. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) determined that the elemental composition had a high percentage of SiO2 and a moderate percentage of Al2O3. This indicates a high amount of quartz-like silica in the sediment in all samples. By analyzing different variations in the chemical, size, and elemental components of sediment, we can infer information about processes, climate conditions, and deposition, which provides us with details about the paleoclimatic conditions of this region.  

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-11336

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