Collaborative Research: Deciphering MIS 5e sea-level changes using U-Th dated fossil corals and cave deposits from the Yucatan Peninsula

Sea-level rise is a major issue affecting coastal communities, infrastructure, and the environment. Flooding already costs the U.S. economy $200 - $400 billion annually, and sea-level rise will worsen flooding impacts for coastal communities, which support 58 million jobs and produce $9.5 trillion in goods and services. This project aims to better constrain the sensitivity of ice sheets to future melting by examining the Last Interglacial period (~ 129,000 to 116,000 years ago), when Earth was slightly warmer and global mean sea level was higher. The research focuses on fossil coral reefs and cave deposits in the Yucatán Peninsula, which preserve an exceptional record of sea-level change. By analyzing and dating these records, the project seeks to reduce uncertainty concerning how fast and how high sea level rose during this period. These insights will improve future projections and contribute to more informed coastal planning. The project fosters international collaboration with active involvement of local researchers, supports two graduate students and two early-career faculty, and includes broad public outreach in the U.S. and Mexico. The project combines fieldwork, laboratory analysis, and modeling to study local sea-level changes in Yucatán, as well as global mean sea level, during the Last Interglacial. Researchers will collect fossil corals from coastal sites, assess their preservation, and determine their ages using uranium-thorium dating. To estimate long-term uplift (or subsidence), they will study cave deposits once near the water table in coastal caves dated to different time periods over the past 300,000 years. The team will also provide new estimates for the effect of karst isostasy to better understand the drivers of long-term deformation. By correcting the local sea-level record for these factors and glacial isostatic adjustment, the researchers aim to produce a more accurate global sea-level reconstruction and explore the processes that caused ice sheets to melt. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.