Carbonate Platform and Coral Reef Response to Environmental Perturbations: Insights from Scott Reef North West Shelf Australia

Abstract

Coral reefs preserve important archives of past sea-level and climatic change due to their depth-dependent growth, good preservation potential, and ability to be precisely dated using U–series techniques. Isolated carbonate platforms along rapidly subsiding continental margins record expanded sea-level histories because sustained subsidence maintains accommodation within euphotic–mesophotic zones, enabling long-term reef accretion and stratigraphic preservation. However, fossil reef cores from such settings are rare, diagenetically altered, and limited by poor spatial and temporal sampling, leaving uncertainties in reef responses to environmental change over millennial timescales. Scott Reef, on Australia’s Northwest Shelf, preserves one of the most continuous Quaternary reef archives in the Indo-Pacific. However, uncertainties remain regarding reef initiation and demise, the impact of the Middle Pleistocene Transition, and controls on long-term reef resilience. This thesis investigates environmental and eustatic controls on carbonate platform evolution across Neogene–Quaternary climate transitions, with relevance to future reef response under changing climate conditions. High-resolution geological models of Scott Reef are developed to assess responses to orbital forcing, sea-level change, and oceanographic variability. The approach integrates forward stratigraphic modelling with multi-scale datasets, including 3D seismic, multibeam bathymetry, reef cores, well logs, U–series geochronology, and modern ecological observations. Methods combine core logging, hyperspectral scanning, neutron computed tomography, and facies analysis to refine lithological interpretation and palaeoenvironmental reconstructions. Coralgal assemblages are used within a chronostratigraphic framework spanning 500 kyr. This integrated approach provides new constraints on Scott Reefs evolution and improves understanding of carbonate platform responses to climatic and oceanographic forcing.