Oxygen isotope (18-O) values for 5 different foraminiferal species down the core of GC12, collected from the Capricorn Channel

A gravity core (GC12) was collected from a depth of 990.5 mbsl within the Capricorn Channel, southern Great Barrier Reef (GBR). The 18-O values of the different foraminiferal species down the depth of the core show relatively consistent inter-species offsets throughout the glacial and interglacial periods. This provides us with confidence that the 5 individual species presumably remained within the same water mass. Because each foraminifera species fractionate carbon and oxygen isotopes differently, amended 18-O values are given whenever possible to account for these well-known biological vital effects. Comparison of the 18-O values with SPECMAP (Martinson et al., 1987) provides us with a chronology for core GC12.

本研究从大堡礁（Great Barrier Reef, GBR）南部摩羯海峡内的990.5米水深（meters below sea level, mbsl）处采集了一根重力岩心（gravity core，GC12）。岩心各深度层位中不同有孔虫物种的18-O同位素比值，在冰期与间冰期均呈现出相对稳定的种间偏移量。这一现象使我们确信，本次分析的5个有孔虫物种大概率处于同一水团之中。由于不同有孔虫物种对碳、氧同位素的分馏效应存在差异，本研究尽可能对18-O同位素比值进行校正，以抵消这些广为人知的生物生命效应。将本次测得的18-O同位素比值与SPECMAP曲线（Martinson等，1987）进行对比，为GC12岩心建立了年代学框架。