Thirty-seven samples were collected from the volcanic ash bed at Ashfall Fossil Beds State Historical Park in Nebraska for geochemical analysis. Two hypotheses are tested: (1) the ash bed is from a single volcanic eruption, and (2) it is correlated to the 11.93 Ma Ibex Hollow tuff. Major and trace element content was determined using an Energy Dispersive X-ray Spectrometer (EDS) and an X-ray Fluorescence Spectrometer (XRF), respectively. Results show one distinct chemical cluster, suggesting a single volcanic source. When these samples are compared with previously published data, the Ashfall ash layer is tentatively correlated to a younger volcanic source, approximately 10.5 Ma. Additional analyses are needed to test the validity of this interpretation.
Dobbins, Jeffrey, "A Geochemical Analysis of the Volcanic Ash Bed Deposit at Ashfall Fossil Beds, Nebraska" (2010). Honors Projects. Paper 8.
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