Paleoceanography of the Cariaco Basin using clumped isotope geochemistry: Last Glacial Maximum to present

Sediments of the Cariaco Basin have been studied extensively over the past two decades through coring campaigns and modern sediment traps, revealing a critical archive of low-latitude paleoclimate and paleoceanographic change during the late Pleistocene and Holocene. In this work, we build on the rich foundation of these prior studies to evaluate questions related to low latitude climate reconstructions from the last glacial maximum (LGM; ~21 kyr B.P) to present.

Using clumped isotope analysis of the planktic foraminifera Globigerinoides ruber, taken from ODP Leg 165 Site 1002 Hole E - in combination with δ¹⁸O and prior published data from a range of proxies - we consider several key research questions: (1) What is the Δ₄₇-reconstructed oxygen isotope value of seawater (δ¹⁸O-sw) and temperature over the past 21,000 years at this site, (2) How does this reconstructed δ¹⁸O-sw compare to other published estimates, and (3) What does it imply about changes in the low-latitude hydrologic cycle - such as dynamics due to the Intertropical Convergence Zone - since the LGM?

Utilizing the Peral et al. 2018 temperature calibration, clumped isotope analysis taken from 9 sampling depths follow the temperature trends from glacial-interglacial cycles from the LGM to present. Additional temperature calibrations Peterson et al. 2018 and Bernasconi et al. 2018, reflect slightly different values, impacting reconstructed temperature and δ¹⁸O-sw values. We plan to explore whether through combination with other types of proxies, and through higher resolution records, it is possible to more robustly constrain temperature and seawater compositions.