ASSESSING THE DIAGENETIC SUSCEPTIBILITY OF THE LARGE SKELETAL ARCHITECTURE CORAL SPECIES HYDNOPHORA MICROCONOS – IMPLICATIONS FOR TROPICAL PALEOCLIMATE RECONSTRUCTIONS

The central tropical Pacific is a major driver for global climate variability yet our understanding of the impacts from human-induced climate change are limited due to sparse instrumental datasets. Quantifying the magnitude and timing of the human-induced warming in the tropical Pacific is essential for evaluating climate models for future impacts with continued greenhouse gas emissions. Geochemical records from corals are a reliable proxy to extend the instrumental climate record beyond the industrial era. To date, most records from living corals from the central tropical Pacific only extend to the early to mid-20^th century. Alternatively, fossil corals are used to extend the record beyond the industrial era but are often sparsely located through time, partially due to the reliance on one key coral genus – Porites – a coral with small skeletal architectural features. However, many studies from the Caribbean Sea have successfully used corals with larger skeletal architecture as reliable recorders of climate. The challenge is that the larger skeletal architecture provides more pathways for water to dissolve the original aragonitic skeleton and recrystallize to calcite, overriding the original climate signal. Using Scanning Electron Microscopy (SEM) and X-Ray diffraction we examine the skeletal preservation of modern and fossil Hydnophora microconos, a large skeletal architectural coral commonly found in the central tropical Pacific, for diagenesis – both the dissolution of the aragonitic skeleton and the recrystallization of calcite. Initial results suggest that the preservation is similar Porites but that each coral should thoroughly be screened for diagenetic alteration prior to being including in any climate reconstruction. By including Hydnophora microconos in central tropical Pacific reconstructions, it opens a vast new archive to help achieve nearly continuous climate records through the pre-industrial era.