(In)coherent multiproxy signals in marine sediments: Implications for high-resolution paleoclimate reconstruction
(In)coherent multiproxy signals in marine sediments: Implications for high-resolution paleoclimate reconstruction
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DOI：
10.1016/j.epsl.2019.03.003
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发表时间：
2019-06-01
影响因子：
5.3
通讯作者：
Eglinton, Timothy I.
中科院分区：
文献类型：
--
作者：
Ausin, Blanca;Magill, Clayton;Eglinton, Timothy I.
准确的年代学是古气候研究的支柱，但对于海洋沉积记录，相同的年龄模型通常应用于可能经历不同沉积前历史的共同评估成分，导致相应代理信号中的混叠。在这里，我们展示了几个代理载体之间的 C-14 年龄差异，并用它们来突出沉积物不同成分之间的时空差异。从葡萄牙西南伊比利亚边缘的所谓“沙克尔顿遗址”取回的沉积岩芯的相应深度区间内，总有机碳（TOC）、烯酮和链烷酸（脂肪酸）的年龄比同时存在的浮游有孔虫更古老。时间差异可以通过添加通过横向平流、河流或风输送到现场的预老化材料来解释。然后，我们对不同池的年龄结构和相对丰度进行了建模，这些池可能有助于 TOC 和烯酮的较旧年龄。结果表明添加了中等比例（15-20%）非常古老的异地材料（18,500-49,900 年）。该信息用于对烯酮衍生的海面温度（SST）记录进行反卷积，并评估异地输入对古气候信号的影响。 (C) 2019 作者。由 Elsevier B.V 出版。这是一篇遵循 CC BY-NC-ND 许可证 (http://creativecommons.org/licenses/by-nc-nd/4.0/) 的开放获取文章。
Accurate chronologies are the backbone of paleoclimate research, yet for marine sedimentary records the same age model is often applied to co-eval components that may have experienced different pre-depositional histories, leading to aliasing in corresponding proxy signals. Here we demonstrate C-14 age discrepancies among several proxy carriers and use them to highlight spatio-temporal disparities among different components of the sediment. Total organic carbon (TOC), alkenones, and alkanoic (fatty) acids have older ages than co-occurring planktonic foraminifera in corresponding depth intervals of a sediment core retrieved from the so-called 'Shackleton Sites' on the southwest Iberian margin off Portugal. Temporal differences are explained by the addition of pre-aged material that is transported to the site by lateral advection, rivers or wind. We then modeled the age structure and relative abundance of the different pools that might have contributed to the older ages of TOC and alkenones. Results suggest the addition of a moderate (15-20%) proportion of very old allochthonous material (18,500-49,900 yr). This information was used to deconvolve the alkenone-derived sea surface temperature (SST) record and assess the impact of allochthonous inputs on paleoclimate signals. (C) 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).