Radiocarbon dating of Loess-Palaeosol-Sequences from Remagen-Schwalbenberg using Earthworm Calcite Granules

使用蚯蚓方解石颗粒对雷马根-施瓦尔本贝格黄土-古土壤序列进行放射性碳测年

• 批准号: 439443769
• 负责人: Dr. Peter Fischer
• 金额: --
• 依托单位: Lehrstuhl für Geomorphologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/439443769?language=en
• 关键词: Radiocarbon; dating; Loess; Palaeosol; Sequences

In the frame of the DFG-funded TERRACLIME-project, precise dating of investigated Loess-Palaeosol-Sequences (LPS) from the Schwalbenberg near Remagen (Middle Rhine valley, Germany) is one of the major challenges. The Schwalbenberg is unique because it preserves a complete terrestrial record of Last Glacial climate variability in western Central Europe, and especially of Marine Isotope Stage (MIS) 3. In context to the documentation and interpretation of millennial-timescale warming periods, named Greenland Interstadials (GI) or Dansgaard-Oeschger events, and their impact on landscape formation the dating approach gains particular importance. The interstadial periods appear as soil horizons of different development degrees within the investigated sequences and can be traced precisely using the multi-proxy-approach elaborated for the TERRACLIME-project. In contrast, the exact chronostratigraphic position remains uncertain, especially due to unfavourable mineralogical characteristics and relatively large error ranges of luminescence ages, which partly exceed the duration of interstadial periods. In this context, a promising dating approach has recently been developed applying radiocarbon dating of fossil Earthworm Calcite Granules (ECG) that shows very promising results for the Nussloch type section and northwestern France (Moine et al., 2017; Prud’homme et al., 2019). This new approach is even more important as conventional 14C-datable remains are scarce in LPS hampering the development of robust radiocarbon chronologies. Within our preparatory studies, a new profile at the Schwalbenberg was prepared and sampled in high resolution (5 cm intervals, 105 samples in total). The profile is characterised by several brown soils, tundra gleys and loess deposits of MIS 3 age, showing particularly high numbers of ECG in palaeosols. First radiocarbon ages significantly improved the age model for the Schwalbenberg LPS and shows that the sampled material is suitable for 14C-dating. Thus, the main objective of this supplementary proposal is radiocarbon dating of additional 40 samples from the Schwalbenberg profile. The data will be integrated into the ongoing work of the TERRACLIME-project and help to validate luminescence ages and refine OSL protocols. Recently, isotope analyses (δ18O und δ13C) have already been conducted on all samples from the new profile. Based on these analyses and the complementary ECG dating approach, it will be possible to interpret essential palaeoclimate data against the background of a robust chronostratigraphy and to compare them to regional and global palaeoclimate archives.

在DFG资助的Terraclime项目的框架中，来自Remagen附近的Schwalbenberg（德国中部莱茵河谷）的Schwalbenberg研究的Loess-Palaeosol-序列（LPS）是主要挑战之一。 The Schwalbenberg is unique because it preserves a complete terrestrial record of Last Glacial climate variability in western Central Europe, and especially of Marine Isotope Stage (MIS) 3. In context to the documentation and interpretation of millennial-timescale warming periods, named Greenland Interstadials (GI) or Dansgaard-Oeschger events, and their impact on landscape formation the dating approach gains particular importance.间质周期作为研究序列中不同发育程度的土壤水平出现，可以精确地追溯到使用用于Terraclime-Project的多种透明度征服。相反，确切的年度地层学位置仍然不确定，特别是由于矿物学特征和发光年龄的相对较大误差范围，这部分超过了内部周期的持续时间。在这种情况下，最近开发了一种有希望的约会方法，该方法采用了化石earth有方解石颗粒（ECG）的放射性碳年代测定，显示了Nussloch类型部分和法国西北部的结果非常有希望的结果（Moine等，2017; Prud'Homme等人，2019年）。这种新方法更为重要，因为传统的14C可依赖的遗体在LP上稀缺，从而阻碍了稳健的放射性碳年代的发展。在我们的准备研究中，制备了Schwalbenberg的新概况，并以高分辨率进行采样（间隔5 cm，总共105个样品）。该轮廓的特征是几个棕色的土壤，苔原gle和MIS 3时代的黄土沉积物，在古质体中表现出尤其大的ECG。第一放射性碳年龄显着改善了Schwalbenberg LPS的年龄模型，并表明采样材料适合14C年期。这是该补充提议的主要目标是从施瓦尔本贝格（Schwalbenberg）剖面的40个样品的放射性碳日期。数据将集成到磨牙项目的正在进行的工作中，并有助于验证发光时代和完善OSL协议。最近，同位素分析（Δ18O和Δ13C）已经对新曲线的所有样品进行了进行。基于这些分析和完整的心电图约会方法，可以根据强大的年度地层学的背景来解释必需的古气候数据，并将它们与区域和全球古气候档案进行比较。