Sea ice and marine climate variability for NW Iceland/Denmark Strait over the last 2000 cal. yr BP
Sea ice and marine climate variability for NW Iceland/Denmark Strait over the last 2000 cal. yr BP
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DOI：
10.1177/0959683609105302
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发表时间：
2009-08-01
期刊：
影响因子：
2.4
通讯作者：
Vare, L. L.
中科院分区：
文献类型：
--
作者：
Andrews, J. T.;Belt, S. T.;Vare, L. L.
MD 99 -2263是从Djupall采集的一个46 cm的箱形岩心，Djupall是一个横穿冰岛大陆架西北部并终止于丹麦海峡上方的海槽。我们提供了一个多代理记录，记录了过去类似于1700年的区域海洋气候变化。深度/年龄模型是基于7个校准的放射性碳日期的软体动物壳和铅-210和铯-137。沉积物积累率是可变的（0.2-0.8毫米/年），但急剧增加，类似于公元1500年。确定了e U mm沉积物部分的粒度、磁性、定量矿物组成、底栖有孔虫组成、底栖和浮游三角洲O-18比率以及海冰生物标志物IP 25的丰度/通量。为了更好地比较各种代理，关键气候代理的TU被协调成100年/样本的时间序列，并通过主成分分析进行了检查。第一轴解释了49%的方差，第二轴解释了另外17%的方差。与第一轴最密切相关的变量是沉积物性质（φ平均值，粘土%）和海冰生物标志物。流冰漂流的矿物学指标，如石英和钾和钠长石的存在，与IP 25生物标志物数据一致，并显示在AD 1200之后增加，但石英和一些长石的高值也发生在c.公元300年和900年之间的AD 900和1100明显的最小值。总的来说，我们的数据表明，在过去的1700年里，气候条件有一个简单的双重划分，主要的变化发生在c。公元1200年在过去的几十年里，情况已经恢复到公元1200年之前的情况。
MD99-2263 is a 46 cm box core collected from Djupall, a trough that cuts across the NW Iceland Shelf and ends above Denmark Strait. We provide a multiproxy record that documents changes in the regional marine climate over the last similar to 1700 yr. The depth/age model is based on seven calibrated radiocarbon dates on mollusk shells and on Pb-210 and Cs-137. Sediment accumulation rates were variable (0.2-0.8 mm/yr) but increased dramatically similar to AD 1500. Grain-size, magnetic properties, quantitative mineral composition of the e U mm sediment fraction, benthic foraminiferal composition, benthic and planktic delta O-18 ratios, and abundances/fluxes of the sea ice biomarker IP25 were determined. To better compare the various proxies, TU of the critical climate proxies were co-ordinated into 100-yr/sample time series, which were examined by Principal Component Analysis. The 1st axis explained 49% of the variance and the 2nd axis explained an additional 17%. The variables most strongly associated with the 1st axis were sediment properties (phi mean, clay%) and the sea ice biomarker. Mineralogical indicators of drift ice rafting, such as the presence of quartz and potassium- and sodium-feldspars, coincide with the IP25 biomarker data and show an increase after AD 1200, but high values of quartz and some feldspars also occurred between c. AD 300 and 900 with pronounced minima between AD 900 and 1100. Overall, our data suggest a simple two-fold division in climate conditions over the last 1700 yr, with the major change occurring c. AD 1200. In the last few decades, conditions have reverted towards those experienced prior to AD 1200.