Twelve reef sediment cores were collected on the leeward reef slope of Clerke Island, QLD, Australia via manual percussion coring on SCUBA in August of 2014. Each of these sediment cores were then divided into 5 cm subsections and sieved to collect clasts >4 mm. The genus of coral clasts >4 mm within each subsection were identified. Biomass of each genus was determined by weighing each sample after drying. Weighing and subsampling of cores occurred in early 2021. This data was collected to assess the temporal changes in coral community composition and understand how coral community dynamics in an isolated reef ecosystem with limited impact from sediment run-off and other localised anthropogenic effects since European colonisation. To temporally constrain the changes in community composition, U-Th dating was conducted on samples within each core. Samples were cut, crushed and cleaned then grains of pure aragonite were selected under a binocular microscope for dating purposes. Analysis occurred at the University of Queensland's Radiogenic Isotope Facility in mid 2021 using a Nu Plasma I Multi-collector Inductively Coupled Plasma Mass Spectrometer.