Holocene Development and Palaeo-oceanography of Scott reef, Western Australia

摘要

Scott Reef is located on the northwest margin of Australia at 14deg03'S and 121deg47'E. It consists of a bifurcated topographic high, at the edge of a carbonate platform established in the Late Eocene. The modern reef system is partially emergent during low tide (4m range), it is exposed to strong swell and Indian Ocean tropical cyclones and located on the main passage of the Indonesian Throughflow (ITF). Nutrient levels are low; temperature ranges between 25-30 degC and salinity 34.5 and 34.7. The Holocene reefs show resilience to bleaching or other oceanographic events. North and South Holocene reefs show similar average accretion rates of ~3.2mm/ yr, however they may have developed morphologically distinctly due to differential accommodation and associated lateral accretion. Reef initiation was established as early as 11.5 ka BP with dominant slow growing domal and tabular branching coral facies in semi-protected sites and coralline algal crusts in more exposed sites. Porites geochemical analysis points to a cooler SST window around 8.3 ka, and a higher SSS window at 5.8 ka (not yet calibrated). These findings extend our knowledge of regional and climatic events through Holocene time.