Forrest McCann L&S Sciences
Modeling Diagenetic Effects on Marine Carbonate Clumped Isotope Values
The stable isotopic composition of marine carbonates is an exemplary standard for reconstructing past Cenozoic climate. But, a fundamental question is whether these carbonates faithfully record their original isotopic composition, and to what extent have they been modified during burial. The relative abundance of isotopologues of carbonate with two rare isotopes (clumped isotopes) is a function of formation temperature and is leveraged to understand how carbonate samples were formed and modified through time. Recent work to reconstruct paleotemperatures from carbonate clumped isotopes found that samples from below 1,000 meters below the sea floor appear to record either a warmer past or a more significant role of diagenetic alteration. My study will focus on measuring carbonate clumped isotopes in an ocean core from the Rio Grande Rise in the Atlantic Ocean. Alongside the measurements, I will also work on a model that characterizes how diagenetic alteration affects the isotopic composition of carbonates. Together, the measurements and model will help me analyze the interplay between warmer ocean temperatures over the Cenozoic and varying rates of diagenetic recrystallization.