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

末次冰期的气候变率比全新世大得多。特别是海洋同位素阶段（MIS）3（ca。57-27 ka）的特点是快速的气候振荡（格陵兰冰间），这表明迅速变暖，然后逐渐冷却。这些国际天文台在中欧的影响尚不清楚。在西欧陆地北方（>50° N），零星的有机沉积物夹在无机冰川沉积物中被解释为间冰柱的证据，花粉分析表明开放，无树植被。在欧洲中部北方，冰丘间的典型特征是苔原植被，灌木和稀疏的北方树木的可变组成部分。由于年代学上的不确定性，将50° N以北的欧洲陆地间冰柱精确归属到格陵兰的特定间冰柱是不可能的。洞穴沉积物具有很大的气候重建潜力，特别是因为它们可以用230 Th/U方法非常精确地定年。在47° N以北，欧洲MIS 3期间的洞穴沉积物生长迄今仅在三个洞穴中被发现。其中两个只有230 Th/U年龄，但没有气候代用数据。因此，只有一个单一的MIS 3洞穴替代时间序列从中欧，这是限制在两个增长阶段，从~52至~51和~47至~43 ka。这表明，气候过于寒冷和/或干燥的MIS 3的大部分地区，使speleothem生长在阿尔卑斯山以北的中欧。在这里，我们建议研究两个speleothem从Bleßberg洞穴，德国东部。这些流石显示了MIS 3期间的几个生长期，这些生长期在中欧的其他洞穴沉积物中尚未发现。这提供了一个独特的机会，以获得精确的古气候信息，这些间隔，这反映了格陵兰interstadials在陆地欧洲的影响。这是特别感兴趣的，因为Bleßberg洞穴位于ca。我们将建立一个精确的MIS 3和晚冰期的多代用指标气候记录，包括洞穴流体包裹体的d13 C和d18 O值、微量元素、Sr同位素以及dD和d18 O值。此外，我们将应用一个独特的和新颖的组合洞穴监测，同位素启用气候建模和建模过程中发生的土壤和岩溶以上的洞穴，以获得更好地了解的过程影响代理信号在洞穴网站和解开影响洞穴d18 O值的因素。这将使我们能够提供MIS 3期间气候变率的定量重建，然后将其与Bleßberg洞穴的全新世代理记录以及其他全球和区域气候记录进行比较，以重建空间变率和潜在的远程连接。

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.