Document Type

Honors Thesis

Semester of Graduation

Spring 2026

Abstract

Rare earth elements (REE) have been recognized within the last decade as important markers of diagenetic activity in fossil apatite. However, little work has been done to explore the influence of diagenesis on bioapatite in continental red bed settings. This study analyzed the REE preserved in a set of preserved Dimetrodon and Eryops teeth from the Clear Fork Formation, a set of Permian red beds near Seymour, Texas. Both Electron Probe Micro-Analysis (EPMA) and Laser-Ablation – Inductively-Coupled Plasma – Mass Spectrometry (LA-ICP-MS) were used to identify the constituent elements of the teeth. Chemical data from the EPMA indicate that the teeth are predominantly fluorapatite in composition. Additionally, barite and other minerals containing iron, lead, and silver were identified within the cracks of these teeth. The LA-ICP-MS data show that the teeth contain a significant amount of REE (5000 – 8000 ppm) and display a pattern of middle-REE enrichment. The barite crystals precipitated in the teeth are exceptionally enriched in Eu. Based on textural relationships, this barite is interpreted as an early diagenetic product and may have influenced the REE content of the adjacent bioapatite. This barite and the hematite common to continental red beds indicate that moderately to strongly oxidizing conditions prevailed during diagenesis; however, further interpretations of diagenesis based on the Ce and Eu anomalies within these teeth is precluded by potential interference of Ba with the REE during data collection. This study reinforces the complicated nature of deciphering diagenetic conditions from bioapatite in continental red bed settings. Further work is needed to explore the interaction of bioapatite and barite during diagenesis via a measurement system that minimizes experimental error and interference between Ba and the REE.

Awardee Name

Anthony Chiasson

Academic Major

Geology

Project Mentor

Achim Herrmann

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