North-Central Section - 42nd Annual Meeting (24–25 April 2008)

Paper No. 6
Presentation Time: 3:20 PM


FARLOW, James O., Department of Geosciences, Indiana-Purdue Univ, Fort Wayne, IN 46805, CHIN, Karen, CU Museum and Department of Geological Sciences, Univ of Colorado at Boulder, UCB 265, Boulder, CO 80309 and ARGAST, Anne, Department of Geosciences, Indiana University Purdue University Fort Wayne, 2101 E Coliseum Blvd, Fort Wayne, IN 46805-1445,

The Pipe Creek Sinkhole (PCS: Pipe Creek Jr. Quarry, Irving Materials Inc., Swayzee, Grant County, Indiana) preserves a diverse assemblage of continental plant and animal fossils of latest Hemphillian (Mio-Pliocene) age. Screen-washing of in situ fossiliferous sediments in 2003 yielded two specimens (lab numbers PCC-1 and PCC-2) that are here identified as coprolites. The oblong masses are about 3 centimeters long, 2-2.5 cm in maximum width, and cylindrical to elliptical in shape. Quantitative electron microprobe maps of PCC-1 revealed that the coprolitic ground mass is dominated by high concentrations of phosphorus and calcium, with minor amounts of manganese and iron. Energy Dispersive X-ray spectroscopy of PCC-2 indicated similarly high contents of P (weight % 14-15; atomic % 10-11) and Ca (weight % 34-35, atomic % 19-20), and lesser amounts of F, Mn, and Fe. These analyses indicate that both specimens are predominantly composed of apatite, a composition consistent with their being coprolites of carnivorous animals. Internally PCC-1 includes numerous parallel linear voids which were once apparently occupied by mammal hairs, as well as a relatively large inclusion that is probably a tooth. PCC-2 is more amorphous internally. Potential producers of the PCS coprolites present in the skeletal fauna include peccaries, felids, ursids, and canids; scat from modern representatives of some of these groups nicely matches the size and shape of the PCS coprolites.