ANALYZING POTENTIAL CHEMICAL VARIABILITY AND ITS RELATIONSHIP TO ENGINEERING PROPERTIES IN THE BURLINGTON-KEOKUK FORMATION, SPRINGFIELD, MISSOURI

The Burlington-Keokuk formation is regionally extensive through Iowa and Missouri and can be roughly-correlated into Arkansas and Oklahoma. This formation is a surficial rock unit in most of the Springfield plateau. It has been studied extensively in Northeast Missouri, Iowa, and Illinois (Banner et al., 1988; Choquette et al., 1991; Hoenig, 2019). Most of these studies looked at the lateral variability of depositional facies with only a few geochemical studies. In southwest Missouri there are a limited amount of geochemical studies. In the Springfield Plateau, many caves, sinkholes, and other karst features exist which appear to relate to the hydrology within the Burlington-Keokuk and adjacent units (Dodd, 2007). This relation may be caused by the amount of chert variability or lithological changes both vertically and horizontally, going from a purely crystalline limestone with an occasional bivalve fossil to a crinoidal packstone. Another change is seen in surface streams, where beds of Burlington-Keokuk appear to serve as aquicludes at certain points in the stream, suggesting vertical variability alongside horizontal change. This project will use geochemical methods to investigate chemical variability in the Burlington-Keokuk. The project will also include LA Abrasion tests to compare chemical differences to the formation’s abrasiveness. Based on literature, it might be possible to observe differences in B/Ga ratios. Anecdotally from local quarry operators suggest that LA Abrasion tests indicate vertical variations, offering a possible chemical reason for the differences. Analytical methods will include Inductive Coupled Plasma Mass Spectrometry and LA Abrasion (ASTM Method C131), expanding as necessary. Areas of interest or question will be studied further as appropriate.