Deep-sea sediments record palaeoenvironmental and oceanographic changes over time through variations in their magnetochemical and sedimentological properties. This study presents the Late Quaternary sedimentary reconstruction of three sediment cores extracted from a source-to-sink sedimentary system located in a high marginal platform of the north-west Iberian Margin. The aim of this reconstruction is to explore the palaeoclimatic, palaeoproductivity and diagenetic changes over the last 172 cal ka bp attending to geochemical, magnetic and sedimentological variations. The record is comprised of four sedimentary units consisting of pelagic, hemipelagic and detrital facies, the latter associated with ice-rafted debris events at Heinrich Stadials. These findings allowed the reconstruction of the lithostratigraphy attending to climatic changes, covering the last eleven Heinrich Stadials. These units and facies successions are controlled by the superposition of the Milankovitch and Dansgaard–Oeschger cycles. Low sedimentation rates have been reported, especially during cold periods. Palaeoproductivity was assessed using total organic carbon and calcium carbonate content, together with biogenic barium (Ba_bio) and organic phosphorus (P_org), both calculated via total digestion analysis using standard calculations. Mass accumulation rates for total organic carbon, Ba_bio and P_org were calculated. Furthermore, a sequential extraction was performed to explore the different phases of the barium within sediments: biogenic barite (Ba_bar), barium associated with iron and manganese oxides (Ba_ox) and Ba associated with aluminosilicates (Ba_det). Results display a limitation in the use of the biogenic barium and phosphorus and mass accumulation rates, suggesting detrital Ba (Ba_detr) contribution during Heinrich Stadials, which could mask the calculations. In contrast, only calcium carbonate fluctuates attending to glacial/interglacial cycles. Regarding some diagenetic proxies (i.e. Mn, Mn/Fe and Mn/Ti), they reveal oxidation fronts of different generations, suggesting that the early diagenesis has not reached steady-state, because the redoxcline fluctuates. This fact suggests an erosional activity that causes the continuous oxygenation of the sediment and non-steady-state conditions.

中文翻译：

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基于古气候、古生产力和成岩证据的加利西亚大陆边缘（伊比利亚半岛西北部）晚第四纪沉积演化

深海沉积物通过磁化学和沉积学特性的变化记录了古环境和海洋学随时间的变化。本研究介绍了从位于伊比利亚西北部边缘高边缘平台的源-汇沉积系统中提取的三个沉积岩心的晚第四纪沉积重建。这次重建的目的是探索过去 172 cal ka bp的古气候、古生产力和成岩作用的变化关注地球化学、磁学和沉积学的变化。该记录由四个沉积单元组成，包括远洋相、半远洋相和碎屑相，后者与海因里希体育场的冰漂碎片事件有关。这些发现允许重建关注气候变化的岩石地层学，涵盖最后 11 个 Heinrich Stadias。这些单元和相序受米兰科维奇旋回和丹斯加德-厄施格旋回的叠加控制。据报道，沉降率低，尤其是在寒冷时期。使用总有机碳和碳酸钙含量以及生物钡 (Ba _bio ) 和有机磷 (P _org)，两者都是通过使用标准计算的总消化分析计算的。计算了总有机碳、Ba _bio和 P _org的质量积累率。此外，进行了连续提取以探索沉积物中钡的不同相：生物重晶石（Ba _bar）、与铁和锰氧化物相关的钡（Ba _ox）和与铝硅酸盐相关的 Ba （Ba _det）。结果显示生物源钡和磷的使用以及质量积累率存在限制，表明碎屑 Ba (Ba _detr) 在 Heinrich Stadias 期间的贡献，这可能会掩盖计算。相比之下，只有碳酸钙会随着冰期/间冰期循环而波动。对于一些成岩作用的代表物（即Mn、Mn/Fe和Mn/Ti），它们揭示了不同世代的氧化前沿，表明早期成岩作用尚未达到稳定状态，因为氧化还原层发生了波动。这一事实表明侵蚀活动导致沉积物的持续氧化和非稳态条件。