Paper No. 63-22
Presentation Time: 2:00 PM-6:00 PM
A CASE STUDY IN TAPHONOMY FROM THE PHILLIPS COAL BALL COLLECTION
The Pennsylvanian (323-299 million years ago) has an exceptional plant-fossil record, in part thanks to coal balls—carbonate nodules containing anatomically preserved peat. The Phillips Coal Ball Collection (PCBC) contains over 50,000 coal balls and 500,000 coal ball peels (acetate “thin sections”). Using these peels, the Phillips lab (University of Illinois, Urbana-Champaign) microscopically analyzed over 800,000 cm2 of plant material, identifying plant occurrences at a taxonomic and tissue/organ level. These researchers used a grid onto each peel and identified the defining tissue or organ in each square centimeter (the “Phillips method”). This study examines the understudied relationship between taphonomy, decay, and recovered diversity. Understanding this relationship could have significant implications for all future analyses of this important paleobotanical dataset, which has been critical to studying plant-climate relationships. We are focused on two Desmoinesian coals, the Herrin and Springfield. Our analysis begins by dividing coal ball peat types into three preservational categories—fibric, hemic, and sapric—which have been applied to modern-day tropical peat-forming mires. We will analyze the composition of the selected peels, leveraging existing data obtained from the PCBC to help us evaluate the link between taphonomy and diversity. Next, we will evaluate estimates of diversity using a newer plant census method—the “tissue tracing method”—which was developed to test the accuracy of the Phillips method. Each tissue is identified and traced in Adobe Photoshop to give a precise representation of its contribution to the total peel area. Here we provide an overview of our methods and early results from our analyses of taphonomy and diversity and the comparison between two diversity estimation methods.