Age vs Depth profile of core GC12, collected from the Capricorn Channel off the Eastern Australian Coast

A gravity core (GC12) was collected from a depth of 990.5 mbsl within the Capricorn Channel, southern Great Barrier Reef (GBR). Isotopic values for 18-O and 13-C were obtained from Globigerinoides ruber and correlated with the SPECMAP age-model. Radiocarbon dating of Globigerinoides sacculifer was also undertaken at nine sample depths, and then corrected and correlated with the curve. This yielded an age vs. depth profile from which it was possible to determine approximate sedimentation rates. From the age-model we see the evidence of MIS 1 through to 5a with sedimentation rates ranging from 2 cm/kyr to 20 cm/kyr, with an average of 10cm/kyr. This is a high sedimentation rate for a sedimentary basin, however the core is situated on the increased slope of the Capricorn Channel, therefore sediments scoured off the shallow gradient slope above may feasibly be focused at this depth on the slope. The sedimentation rate exhibits a unorthodox pattern, with a very high rate (25 cm/kyr) during the middle of MIS 3.

研究人员从大堡礁（Great Barrier Reef, GBR）南部摩羯海峡内海平面以下990.5米（meters below sea level, mbsl）处采集了一根重力岩芯（GC12）。研究人员针对红拟抱球虫（Globigerinoides ruber）的氧18（¹⁸O）与碳13（¹³C）同位素值开展了测定，并将其与SPECMAP年代模型（SPECMAP age-model）进行关联比对。同时，研究人员对9个样品层位的袋拟抱球虫（Globigerinoides sacculifer）实施了放射性碳定年，经校正后将结果与该年代曲线进行匹配，由此获得了年龄-深度剖面，据此可估算得到近似沉积速率。基于该年代模型，可识别出从海洋同位素阶段1（Marine Isotope Stage 1, MIS 1）至5a的沉积记录，其沉积速率介于2 cm/kyr至20 cm/kyr之间，平均沉积速率为10 cm/kyr。该沉积速率对于沉积盆地而言处于较高水平，但由于该岩芯坐落于摩羯海峡的坡度抬升区域，因此上方缓坡被冲刷下来的沉积物理论上可在此斜坡区域汇聚。该岩芯的沉积速率呈现出非常规的变化模式，其中在海洋同位素阶段3（Marine Isotope Stage 3, MIS 3）中期出现了高达25 cm/kyr的沉积速率。