Other Oceanography and Atmospheric Sciences and Meteorology Commons^™

Assessing Delta Oxygen-18 In The Coral Genus Isopora For Reconstructing Indo-Pacific Regional And Seasonal Climate, Gavin Lemley

Legacy Theses & Dissertations (2009 - 2024)

Paleoclimate reconstructions often utilize coral reefs with very long time spans such as the genus Porites and Diploastrea, because of their potential to provide centuries of continuous climate records via geochemical signatures. Smaller corals, such as the genus Isopora, have been essentially unexplored as climate archives because their small skeletons (<1 m) and short lifespans (years to decades) do not provide such continuous geochemical records. There has not been a practical application for such corals until recently. In early 2010, the Integrated Ocean Drilling Program Leg 325 (IODP-325) cored drowned fossil reefs off the Great Barrier Reef (GBR) with the objectives of reconstructing sea level and surface ocean conditions since the Last Glacial Maximum. Out of 213 massive fossil corals that were recovered, most were massive Isoporan colonies. A 30-specimen subset of these fossils range in age from ~32,000 to ~11,500 years before present with even temporal spacing, based on preliminary U/Th dating of core catcher samples. This age distribution is excellent for meeting IODP-325 objectives, but the suitability of Isopora for paleoclimate analyses remains unknown.