Palaeoenvironmental records from the West Antarctic Peninsula drift sediments over the last 75 ka
Palaeoenvironmental records from the West Antarctic Peninsula drift sediments over the last 75 ka
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过去 75 ka 西南极半岛漂移沉积物的古环境记录
DOI：
10.1144/sp381.12
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Vautravers M
中科院分区：
文献类型：
--
作者：
Vautravers M
我们提出了一个多代理研究结果的海洋沉积物岩心JR 179-PC 466恢复从顶部的沉积物漂移在西南极半岛在约2300米的水深。10.45米长的岩芯主要由冰海陆源沉积物组成，仅含微量碳酸钙（< 1重量%）。尽管钙质有孔虫的丰度很低，但在三分之二的研究样品中，钙质有孔虫壳的数量足以进行稳定同位素分析。岩心年代学是基于氧同位素地层学及其相对古地磁强度（RPI）与叠加参考曲线的对比。根据年龄模型，PC 466岩芯跨越过去75 ka，平均沉积速率在4 ~ 25 cm ka− 1之间。整个岩芯中浮游有孔虫丰度在每克0到30个个体之间波动，在海洋同位素阶段（MIS）2（距今14-29 ka，BP）和MIS 4（距今57-71 ka）期间观察到最小值。浮游有孔虫存在于全新世，但更丰富的沉积物沉积在MIS 3（29-57 ka BP），由于较少稀释陆源碎屑和/或更好的碳酸盐保存。在MIS 3期间，最大有孔虫与EPICA德龙宁毛德地（EDML）冰芯的δ 18 O信号记录的南极变暖事件相关。它们表明，在此期间，南极半岛西部的浮游有孔虫产量较高，碳酸盐保存较好。冰筏碎屑（IRD）在PC 466核心的丰度增加，在最后一次冰消期约19和11 ka BP之间，当许多冰山漂流在核心网站，从而释放IRD。在此期间，海平面上升破坏了南极半岛（APIS）和南极西部（WAIS）冰盖的稳定性，这些冰盖在末次冰盛期（LGM; c）的海平面低水位期间前进到大陆架上。19-23 ka BP）。总的来说，我们的研究结果表明，它是可能的，以建立一个年龄模型和重建古海洋和气候变化的高时间分辨率从沉积序列恢复在2300米水深从西南极漂移。
We present results of a multi-proxy study on marine sediment core JR179-PC466 recovered from the crest of a sediment drift off the West Antarctic Peninsula at approximately 2300 m water depth. The 10.45 m-long core consists dominantly of glaciomarine terrigenous sediments, with only traces of calcium carbonate (< 1 wt%). Despite the very low abundance of calcareous foraminifera, planktonic shell numbers are sufficient for stable isotope analyses in two-thirds of the samples studied. The core chronology is based on oxygen isotope stratigraphy and correlation of its relative palaeomagnetic intensity (RPI) with a stacked reference curve. According to the age model, core PC466 spans the last 75 ka, with average sedimentation rates of between about 4 and 25 cm ka− 1. Planktonic foraminifera abundances fluctuate between 0 and 30 individuals per gram throughout the core, with minima observed during Marine Isotope Stage (MIS) 2 (14–29 ka before present, BP) and MIS4 (57–71 ka BP). Planktonic foraminifera are present in the Holocene but more abundant in sediments deposited during MIS3 (29–57 ka BP), owing to less dilution by terrigenous detritus and/or better carbonate preservation. During MIS3, foraminifera maxima correlate with Antarctic warming events as recorded in the δ 18 O signal of the EPICA Dronning Maud Land (EDML) ice core. They indicate higher planktonic foraminifera production and better carbonate preservation west of the Antarctic Peninsula during that time. The abundance of ice-rafted detritus (IRD) in core PC466 increased during the last deglaciation between about 19 and 11 ka BP, when numerous icebergs drifted across the core site, thereby releasing IRD. During this time, sea-level rise destabilized the Antarctic Peninsula (APIS) and West Antarctic (WAIS) ice sheets that had advanced onto the shelf during the sea-level low-stand of the Last Glacial Maximum (LGM; c. 19–23 ka BP). Overall, our results demonstrate that it is possible to establish an age model and reconstruct palaeoceanographical and climatic changes at high temporal resolution from sedimentary sequences recovered at 2300 m water depth from a West Antarctic drift.
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