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Specialist sampling of massive Porites

Identification of massive Porites

Massive colonies of Porites suitable for paleoclimatic studies were visually identified in core sections through the transparent liners prior to core splitting. Those core sections containing massive Porites longer than the core diameter (or shorter but apparently in good condition) were labeled to prevent them from being split using the regular core-splitting procedure. The major goal was to recover pristine, long, continuous intervals of the Porites skeleton from individual colonies along the major axis of growth. The regular core-splitting procedure does not take account of the major growth direction of Porites colonies, which can be different from the core axis, or holes within a colony as a result of bioerosion, which can interrupt an otherwise continuous interval of the Porites skeleton. Therefore, the liner was split for core sections containing Porites colonies using a handheld electric saw. One half of the liner was removed, and photographs of the colonies within the core were taken for reference.

Splitting of massive Porites

Massive Porites were taken out of the core liner and split along the plane of the corals’ major growth direction using a rock saw with a 1 mm thick blade and tap water. This resulted in two nonequal parts, so the procedure outlined in Figure F15 was followed to preserve 50% of the core volume for the archive half. One part was declared to be the archive half of the Porites colony and the other the working half. A 1 cm thick slab was cut from the working half of the Porites colony for paleoclimatic studies. A second 0.8 cm thick slab was cut from the working half for other purposes (e.g., dating, further geochemical studies). In cases where the 0.8 cm thick slab appeared to provide the better sample, it was selected for paleoclimatic studies and the 1 cm thick slab was used for other purposes. The parts of the core without Porites colonies were then cut in half, and the archive and working halves were placed in their respective D-tubes.

Washing and drying of Porites slabs for paleoclimatology

After slicing, Porites slabs for paleoclimatic studies were washed with tap water and dried at 50°C in an oven for ~24 h.