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Timing and trigger mechanisms of abrupt cold events during the Holsteinian interglacial based on analyses of annually laminated sediments

基于年度层状沉积物分析的荷尔斯泰因期间冰期突然寒冷事件的时间和触发机制

基本信息

批准号：
16789302
负责人：
Privatdozent Dr. Ulrich Müller
金额：
--
依托单位：
Institut für Geowissenschaften (IfG)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2006
资助国家：
德国
起止时间：
2005-12-31 至 2010-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/16789302?language=en
关键词：
Timing trigger mechanisms abrupt cold

项目摘要

The Holsteinian interglacial has been correlated with marine Isotope substage 11 c, which is centred at around 400,000 yr BP (Beaulieu et al. 2001, Tzedakis et al. 2003). During that time the climate forcing, i.e. the orbitally driven Insolation and concentration of greenhouse gases, was most similar to the present Situation (Berger & Loutre 2002, ERICA members 2004). Therefore, marine isotope substage 11 c and its terrestriai equivalent, the Holsteinian, are considered äs the best paleoclimatic analogues for the Holocene (McManus et al. 2003, Kukla 2003). In this context, two cold events manifested by the abrupt decline of several thermophile tree species within the Holsteinian interglacial at several sites across NW-Europe (e.g. Turner 1970, H. Müller 1974, Binka & Nitychoruk 1995), gain new relevance. What was the origin and timing of these abrupt cold events which occurred during an interglacial that represents the best analogue to our present Holocene? Here it is proposed to investigate the exact timing and trigger mechanisms of these events based on analyses of annually laminated lake Sediments from Dethlingen (N-Germany). Due to own preliminary work, the core material is already available and low-resolution pollen analyses have been performed to ensure the core indeed comprises the Holsteinian. Now it is proposed to perform varve counting and high-resolution (decadal to centennial scale) pollen analyses for the entire record. In particular, it is proposed to perform ultra-high-resolution (annual resolution) analyses of pollen, geochemical, and geophysicai parameters on the critical inten/als of the two cold events. The ultra-high-resolution analyses of the annually laminated sediment will provide information about the exact timing and thus information about the mechanisms that triggered the abrupt coolings within interglacial boundary conditions.

霍尔斯泰纪间冰期与海洋同位素11c亚阶段相关，11c阶段的中心位置约为40万年BP(Beaulieu等人)。2001年，Tzedakis等人。2003年)。在此期间，气候强迫，即轨道驱动的温室气体日照和浓缩，与目前的情况最为相似(Berger&Loutre 2002，Erica Members 2004)。因此，海洋同位素11c亚期和它的陆相等价物Holsteian被认为是全新世最好的古气候相似物(McManus等人。2003年，库克拉2003年)。在这方面，两个寒冷事件，表现为在整个欧洲西北部的几个地点，霍尔斯泰因间冰期的几个嗜热树种突然减少(例如，Turner 1970，H.Müler 1974，Binka&Nitycluk 1995)，获得了新的相关性。这些发生在间冰期的突如其来的寒冷事件的起源和时间是什么，这是与我们现在的全新世最相似的？在这里，建议根据对Dethlingen(德国北部)每年的层状湖泊沉积物的分析，研究这些事件的确切时间和触发机制。由于自己的初步工作，岩心材料已经可用，并进行了低分辨率的孢粉分析，以确保岩心确实包括霍尔斯泰期。现在建议对整个记录进行伏特计数和高分辨率(十年到百年尺度)的花粉分析。特别是，建议对这两次冷事件的临界点进行花粉、地球化学和地球物理参数的超高分辨率(年分辨率)分析。对每年的层状沉积物的超高分辨率分析将提供关于确切时间的信息，从而提供关于在间冰期边界条件下触发突然冷却的机制的信息。