Quantifying the isotopic composition of oxygen and carbon with increasing depth in core GC11, located in the Capricorn Channel

A gravity core (GC11) was collected from a depth of 502 mbsl within the Capricorn Channel, southern Great Barrier Reef (GBR). The data from stable isotopes of Globigerinoides ruber were analysed to allow a preliminary understanding of the hemipelagic sedimentary environment over the last glacial / interglacial cycle. The results suggest that the core reaches the Last Glacial Maximum (LGM) at ~30cm depth. From matching the 18O G. ruber curve with Martinson et al. (1987), 4 glacial cycles can be determined, incorporating Marine Isotope Stage (MIS) 1 through to MIS 11. Isotopically heavier 18O values at ~460cm, ~345cm, 150cm, and 30cm correspond respectively to MIS 10, MIS 8, MIS 6 and the LGM. The d13C shows a trough lagging behind the 18O high during the glacial, although there are considerable fluctuations between MIS 8 and 6.

研究人员从大堡礁（Great Barrier Reef, GBR）南部摩羯水道（Capricorn Channel）的水下502米（meters below sea level, mbsl）处采集了编号为GC11的重力岩心（gravity core）。对红拟抱球虫（Globigerinoides ruber）的稳定同位素进行分析，以初步解析末次冰期-间冰期旋回内的半远洋沉积环境。结果显示，该岩心约30cm深度处对应末次盛冰期（Last Glacial Maximum, LGM）。通过将红拟抱球虫的δ¹⁸O曲线与Martinson等人（1987）的研究成果匹配，可识别出4个冰期旋回，涵盖海洋同位素阶段（Marine Isotope Stage, MIS）1至11。约460cm、345cm、150cm及30cm处的δ¹⁸O偏重值，分别对应海洋同位素阶段10、8、6及末次盛冰期。冰期阶段的δ¹³C表现为滞后于δ¹⁸O高值的谷值特征，尽管在海洋同位素阶段8至6之间存在显著波动。