A Younger Dryas varve chronology from the Rehwiese palaeolake record in NE-Germany
A Younger Dryas varve chronology from the Rehwiese palaeolake record in NE-Germany
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DOI：
10.1016/j.quascirev.2011.12.010
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发表时间：
2012-03-12
影响因子：
4
通讯作者：
Brande, Arthur
中科院分区：
文献类型：
--
作者：
Neugebauer, Ina;Brauer, Achim;Brande, Arthur
德国东北部第一个1400年来的浮式水华年代学由雷威斯古湖沉积记录中的微观水华计数建立起来，涵盖了从阿尔勒晚期到全新世早期。Laacher See Tephra(LST)位于研究区间的底部，形成了Tephra年代学上的锚点。用微相和Mu-XRF分析相结合的方法研究了这些细小的纹层，它们是方解石变体的典型特征，在这种情况下，它主要提供了温暖的季节信号。划分出两种不同亚层结构的旋涡类型：(I)由多至四个季节亚层组成的复合型旋涡，形成于阿拉尔和全新世早期；(Ii)仅出现在较年轻的仙女座时期的简单两个亚层型旋涡。通过对两个独立分析的沉积物剖面进行基于明确定义的微标志层的逐次对比，提高了年代学的精度。这使得(1)单个缺失的准确位置在其中一个沉积物剖面中变化，以及(2)在平行岩心的扰动的VVE间隔中验证VVE内插。沉积物沉积过程的年际和十年尺度变异性是通过多指标数据系列追踪的，这些数据系列包括季节性层厚度、高分辨率元素扫描以及五个分辨率的有机和无机碳总量数据。这些数据支持两个阶段年轻仙女木的想法，第一阶段(12,675-12,275年BP)以暖季方解石降水仍然显著但逐渐减少为特征，第二阶段(12,275-11,690年BP)仅有微弱的方解石降水。这两个阶段与基于LST等时线和独立波峰计数的MeerFelder Maar记录的详细对比提供了从西部北大西洋附近到东部更大陆的样带(C)2011 Elsevier Ltd.的YD气候变化的区域差异和季节性方面的线索。
The first 1400-year floating varve chronology for north-eastern Germany covering the late Allered to the early Holocene has been established by microscopic varve counts from the Rehwiese palaeolake sediment record. The Laacher See Tephra (LST), at the base of the studied interval, forms the tephrochronological anchor point. The fine laminations were examined using a combination of micro-facies and mu XRF analyses and are typical of calcite varves, which in this case provide mainly a warm season signal. Two varve types with different sub-layer structures have been distinguished: (I) complex varves consisting of up to four seasonal sub-layers formed during the Allered and early Holocene periods, and, (II) simple two sub-layer type varves only occurring during the Younger Dryas. The precision of the chronology has been improved by varve-to-varve comparison of two independently analyzed sediment profiles based on well-defined micro-marker layers. This has enabled both (1) the precise location of single missing varies in one of the sediment profiles, and, (2) the verification of varve interpolation in disturbed varve intervals in the parallel core. Inter-annual and decadal-scale variability in sediment deposition processes were traced by multi-proxy data series including seasonal layer thickness, high-resolution element scans and total organic and inorganic carbon data at a five-varve resolution. These data support the idea of a two-phase Younger Dryas, with the first interval (12,675-12,275 varve years BP) characterised by a still significant but gradually decreasing warm-season calcite precipitation and a second phase (12,275-11,690 varve years BP) with only weak calcite precipitation. Detailed correlation of these two phases with the Meerfelder Maar record based on the LST isochrone and independent varve counts provides clues about regional differences and seasonal aspects of YD climate change along a transect from a location proximal to the North Atlantic in the west to a more continental site in the east (C) 2011 Elsevier Ltd. All rights reserved.