Compositional Variance in the Plattsmouth Limestone Member (Pennsylvanian) in Kansas

Abstract

The compositional variance between samples of the Plattsmouth Limestone Member of the Oread Limestone, Shawnee Group (Late Pennsylvanian age) was studied with respect to the distance between sample locations . Nine samples spaced approximately 150 to 200 feet apart were collected from an underground quarry in Atchison County, Kansas, analyzed, and the compositional variance compared with that of 11 outcrop samples collected on a spacing of approximately 6 miles. Results indicate that at the 95-percent confidence level, the variances are equal. It is concluded that chemical data can be used to depict trends within the Plattsmouth Limestone Member when sample locations are spaced as much as 6 miles apart. The study also demonstrates that, because of the variance, a series of samples should be collected from a given area and analyzed before economic development is begun. It is also concluded that the results of this study may then be generally applied to many of the limestones of Pennsylvanian age from the Midcontinent area.