| Sea-level reconstructions from Pacific Islands generally agree with model predictions (ICE-5G) that regional variations in Earth's viscoelastic response to deglaciation produce unique sea-level histories in particular island settings. Coral reef proxies of sea-level movements vary in their temporal and spatial response to sea-level change, wave energy, and antecedent topography, often limiting their ability to validate model predictions.; Detailed substrate mapping and 32 drill cores from the windward fringing reef of Kailua Bay, Oahu, Hawaii indicate that Holocene reef accretion initiated ca. 7900 yr BP at −24 m and distinct architectural styles of development resulted from differential wave exposure. The topography of a drowned paleostream exerted a fundamental control by providing accommodation space below wave scour for more than 11 m of vertical accretion. The internal core of the reef consists of more than 4 m of rudstone, including stricture that preserves the paleostream meanders. Persistent tradewind waveforcing has promoted prolific coralline algae growth, sediment production, and cementation that reduce porosity and enhance lithification. Plasticity, the capacity to adopt a variety of colony forms, has enabled a few resilient coral species including Porites lobata, Montipora patula, and M. capitata to adapt to physical stress and dominate in environments less suitable for other species. The modern surface community is characterized by six distinct cor-algal reef communities exhibiting different stages of succession, although little accretion has occurred since 3500 yr BP due to century-scale wave disturbance. Because of limited accommodation space for Holocene reef development on Oahu, favorable settings for accretion have been sites of low topography, below wave scour (and concussion) and areas of wave energy dissipation. Differential island subsidence controls reef accretion signatures between the main Hawaiian Islands, while wave energy, through its modulation of accommodation space, largely governs reef development within individual islands. |
