MATERIAL AND METHODS:

　

Cores were collected from living and fossil Porites sp. corals at sites at Laing Island and at Madang (Figure 1). The living corals both grew in about 5m water depth, and, from its location in the reef, the fossil coral described here is believed to have grown in a similar, or slightly shallower water depth. The coral cores were cut into 10mm thick slabs, then sub-sampled down the growth axes into 1mm or 2mm growth increments using a slow speed milling device. Subsamples of 0.5-1.0mg weight were analysed on a VG PRISM III isotope ratio mass spectrometer with automatic carbonate preparation system. Long term analytical precision as determined by analysis of internal consistency standards is ±0.08% δ¹⁸O(one sigma). All carbonate isotopic analyses are quoted relative to V-PDB. Chronologies for each record were constructed based on the annual cycle of δ¹⁸O and supported by the presence of well-defined annual fluorescent banding.

FIGURE 2:　Modern coral δ¹⁸O records from Papua New Guinea. Sample data (〜8-15 samples / year).

Note:　the two coral sites are 150km apart (Figure. 1)

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