EXTRACTING TEMPERATURES FROM FORAMINIFERAL δ18O: MODEL-DATA APPROACHES AND A NEW ONLINE TOOL

Oxygen isotope measurements (δ¹⁸O) from the shells of foraminifera are one of the most data-dense and high-resolution proxy archives for reconstructing marine temperatures and climate transitions, but their interpretation has historically been complicated by diagenetic overprinting and uncertainties surrounding the δ¹⁸O of the seawater in which the shells grew. Seawater δ¹⁸O is both spatially and temporally variable and is strongly influenced by both global ice volume and local climate-dependent hydrology. We review recent advances in oxygen-isotope temperature reconstructions and demonstrate how coupling δ¹⁸O measurements to isotope-enabled general climate models (GCMs) can yield coherent δ¹⁸O-based sea-surface temperatures which are consistent with other temperature proxies, even in traditionally difficult cases such as the Early Eocene. We present a new online tool that automates both traditional and novel δ¹⁸O-temperature conversion methods.