Quantitative climate reconstruction for MIS 3 in Central Europe based on multi-proxy data from precisely dated speleothems (flowstones) from Bleßberg Cave, Germany

基于来自德国布莱伯格洞穴精确年代的洞穴沉积物（流石）的多代理数据，对中欧 MIS 3 进行定量气候重建

• 批准号: 449287287
• 负责人: Professor Dr. Denis Scholz
• 金额: --
• 依托单位: Sektion 4.3: Klimadynamik und Landschaftsentwicklung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/449287287?language=en
• 关键词: Quantitative; climate; reconstruction; MIS; Central

The last glacial period exhibited much larger climate variability than the Holocene. In particular, Marine Isotope Stage (MIS) 3 (ca. 57-27 ka) was characterised by rapid climate oscillations (the Greenland Interstadials), which show rapid warming followed by gradual cooling. The impact of these interstadials in Central Europe is not clear yet. In terrestrial northern western Europe (>50° N), fragmentary organic deposits intercalated in non-organic glacial deposits are interpreted as evidence for interstadials, and pollen analysis indicates open, treeless vegetation. In northern central Europe, interstadials are typically characterised by tundra vegetation with a variable component of shrubs and sparse boreal trees. Due to chronological uncertainties, precise assignment of the terrestrial European interstadials north of 50° N to particular Greenland Interstadials is not possible.Speleothems have great potential for climate reconstruction, in particular because they can be dated very precisely by the 230Th/U-method. North of 47° N, speleothem growth during MIS 3 in Europe has so far only been detected in three caves. For two of those, only 230Th/U-ages, but no climate proxy data have been reported. Thus, there is only a single MIS 3 speleothem proxy time series from Central Europe available, which is restricted to two growth phases from ~52 to ~51 and ~47 to ~43 ka. This suggests that climate was too cold and/or dry during large parts of MIS 3 to enable speleothem growth north of the Alps in Central Europe.Here we propose to study two speleothems from Bleßberg Cave, eastern Germany. These flowstones show several growth periods during MIS 3 that have not been detected yet in other speleothems from Central Europe. This provides the unique opportunity to obtain precisely dated palaeoclimate information for these intervals, which reflect the impact of Greenland interstadials in terrestrial Europe. This is of particular interest because Bleßberg Cave is located at ca. 50 °N, beyond the northern limit for temperate forest development during MIS 3 in Europe.We will generate a precisely dated multi-proxy climate record for MIS 3 and the Late Glacial including d13C and d18O values, trace elements, Sr isotopes as well as dD and d18O values in speleothem fluid inclusions. Furthermore, we will apply a unique and novel combination of cave monitoring, isotope-enabled climate modelling and modelling of processes occurring in the soil and karst above the cave to obtain a better understanding of the processes influencing the proxy signals at the cave site and to disentangle the factors influencing the speleothem d18O values. This should enable us to provide a quantitative reconstruction of climate variability during MIS 3, which will then be compared with Holocene proxy records from Bleßberg Cave as well as with other global and regional climate records to reconstruct spatial variability and potential tele-connections.

上一次冰期的气候变化比全新世要大得多。特别是，海洋同位素阶段3(约57-27ka)的特点是气候快速振荡(格陵兰岛间期)，表现为快速变暖，然后逐渐变冷。这些中间协议对中欧的影响尚不清楚。在西欧北部陆地(&gt；50°N)，夹在非有机冰川沉积中的碎屑有机沉积被解释为冰间沉积的证据，而孢粉分析表明是开阔的、没有树木的植被。在中欧北部，中间地带的典型特征是苔原植被，其中有可变成分的灌木和稀疏的北方乔木。由于年代学上的不确定性，不可能准确地将北纬50°以北的欧洲陆源间期指定给格陵兰间期。洞穴具有巨大的气候重建潜力，特别是因为它们可以通过230°U方法进行非常精确的测年。在北纬47°以北，到目前为止，在欧洲MIS3期间只在三个洞穴中发现了洞穴洞穴。其中两个只有230岁/U岁，但没有气候代理数据报告。因此，只有一个来自中欧的MIS3洞穴群代理时间序列，它被限制在从~52到~51和~47到~43 ka的两个增长阶段。这表明，在MIS3的大部分地区，气候太冷和/或太干燥，不利于中欧阿尔卑斯山以北的洞穴生长。在这里，我们建议研究来自德国东部布勒贝格洞穴的两个洞穴。这些流石显示了在MIS3期间尚未在中欧其他洞穴中检测到的几个增长期。这提供了获得这些时间间隔的精确年代的古气候信息的独特机会，这些信息反映了格陵兰间期在欧洲陆地上的影响。这一点特别令人感兴趣，因为布勒贝格洞穴位于大约50°N，超出了欧洲MIS3时期温带森林开发的北部界限。我们将生成MIS3和晚冰川时期的精确年代多指标气候记录，包括洞穴流体包裹体中的d13C和d18O值、微量元素、锶同位素以及Dd值和d18O值。此外，我们将应用洞穴监测、同位素气候模拟和洞穴上方土壤和岩溶过程模拟的独特和新颖的组合，以更好地了解影响洞穴遗址代理信号的过程，并解开影响洞穴d18O值的因素。这将使我们能够在管理信息系统3期间提供气候可变性的定量重建，然后将其与来自Bleçberg Cave的全新世替代记录以及其他全球和区域气候记录进行比较，以重建空间可变性和潜在的远程联系。