T101 36th Annual Undergraduate Research Exhibition Sponsored by Sigma Gamma Epsilon (Posters)

Monday, 23 September 2024
8:00 AM - 5:30 PM
Hall D

STABLE ISOTOPE PALEOECOLOGY OF THE MAMMOTH FROM SILVER CREEK JUNCTION (UTAH, USA)

Paper number: T101-18
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

Mammuthus is a now extinct member of the Elephantidae family. Mammoths were widespread throughout the Americas and Europe during the Pleistocene. The exact cause of their extinction is unknown, which makes new information on the genus of particular interest. This study focuses on reconstructing the paleoecology and paleoclimatology of mammoths’ habitat using the 13C/12C and 18O/16O isotope ratios in their tooth enamel. Tooth enamel was analyzed because its stable isotope composition is thought to be resistant to diagenetic alteration. The fossil teeth were found at Silver Creek Junction, about 5 km north of Park City (Utah). Carbon-14 dating of an unidentified bone from the deposit provided an age of 42907±518 years BP. A total of 81 serial samples from 4 different teeth were collected at various distances from the occlusal surface and analyzed for their carbon and oxygen stable isotope composition. The average (±1 sd) δ13CV-PDB and δ18OV-SMOW values were -9.1±1.3‰ and 18.4±2.7‰, respectively. The δ13C value reflects the animal’s diet and can be used to reconstruct whether they were primarily eating C3 or C4 plants and what type of environment they lived in. Using an estimated body mass of 8000 kg, we calculated an enrichment factor of 15‰ in the enamel versus diet. This means that the average δ13C value of the diet was -24.1±1.3 ‰, which corresponds to C3 plants in a woodland or mesic woodland-grassland environment. Elephantidae are water dependent which means that the δ18O value of their enamel correlates with the δ18O value of drinking (environmental) water. Using modern transfer functions between elephant enamel and meteoric precipitation, we calculated a δ18O value of -14.4±1.0‰ for local precipitation, which is similar to the modern value (-14.3±0.5‰), suggesting similar mean annual temperature ∼40 ka as today. Additionally, the intra-tooth variability in δ13C and δ18O values can be used to infer potential migrations. The average intra-tooth range of our samples is 2.1±0.9‰ and 2.6±0.5‰ for δ13C and δ18O values, respectively, with the δ18O values showing a clear sinusoidal pattern. Similar amounts of intra-tooth variation in δ13C and δ18O values might suggest that the animals were not migrating long distances.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-400580

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