REE DISTRIBUTION IN UNDERCLAYS FROM TWO PENNSYLVANIAN CORES IN KENTUCKY

As part of a regional USGS-funded Earth MRI project, the Kentucky Geological Survey (KGS) has sampled multiple Middle Pennsylvanian underclays from one core each in eastern and western Kentucky. This is part of a collaborative project led by the West Virginia Geological Survey with participation by state geological surveys in Indiana, Iowa, Illinois, Ohio, Pennsylvania and Maryland. Individual states have freedom to select specific sampling targets, but an overall goal is to collect samples from Middle Pennsylvanian underclays to allow geographic comparison within the stratigraphic framework of previous work in the northern Appalachian basin that focused on Upper Pennsylvanian underclays and paleosols.

The two cores in Kentucky were initially selected for their stratigraphic coverage; additional considerations included the diameter and condition of rock core and availability in the KGS core repository. COVID conditions and project budget constraints precluded consideration of collecting new rock core. The eastern Kentucky core was KGS call number 334 from the Fallsburg quadrangle; the western Kentucky core was call number 546 from the Smith Mills quadrangle. Samples were generally collected on one-foot intervals throughout the zone of visible pedogenic influence below coal zones and in noted areas of paleosol development. All samples were analyzed at the designated USGS contract lab following program specifications. Results are summarized as total REE, total REE+Y, and total REE+Y+Sc. Results will be reported here as total REE.

The samples from the two Kentucky cores range from 72ppm to 812 ppm total REE. The mean is 286ppm. A cluster of the highest values were associated with the West Ky No 6 (Davis) coal underclay in the western Kentucky core (KGS 546). All other samples in both cores were generally more moderate; a single high measurement in the eastern Kentucky core does not match a corresponding duplicate and is questionable.