Samantha L. Zullo


Presentation: 9:00-10:15, Kennedy Union Ballroom



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Paleoclimate reconstructions play a pivotal role in understanding the drivers for environmental change and climate variability. In order to reconstruct the paleoclimate, it is necessary to understand the relationship between the isotopic values of the water, carbonates, and the temperature during the time of their formation. To do so, shell and water samples were collected from seven locations: five in the Great Miami River Watershed, one from the Little Miami River Watershed, and one from the Scioto River Watershed. Four of the locations were lacustrine, while the remaining three were fluvial environments. The growth increments in the shells preserve valuable seasonal to interannual environmental signals, enabling the reconstruction of paleoclimate variables such as temperature and isotopic values. The stable isotope values of δ¹⁸O from the water and shells and δ¹³C from the shells were analyzed using mass spectrometry. The temperature was calculated using the classic paleothermometry equation: T(℃) = 15.73 - 4.30 (δ¹⁸OC - (PDB) - δ¹⁸OW - SMOW) + 0.141 (δ¹⁸OC - (PDB) - δ¹⁸OW - SMOW)2. The equation, δ¹⁸OCarbonate = 1.75 (δ¹⁸OWater) + 5.65, was obtained through the calibration of the carbonate and water isotopes; the trend that was observed for each location showed the lacustrine environments as being more enriched in δ¹⁸O compared to the fluvial environments. One location, Doctor Bowers Lake, fell in between the two, attributed to 18O-depleted groundwater sources for the lake. This study is significant in serving as a baseline and interpretive framework for biogenic carbonate formation and interpretation of paleoclimate and paleohydrology for the Great Miami River Valley and Midwestern region.

Publication Date


Project Designation

Capstone Project

Primary Advisor

Zelalem K. Bedaso

Primary Advisor's Department



Stander Symposium, College of Arts and Sciences

Institutional Learning Goals

Practical Wisdom

Understanding Modern Environmental Controls of Biogenic Carbonate Formation for Paleoclimate Reconstruction