Evidence of the final drainage of the Baltic Ice Lake and the brackish phase of the Yoldia Sea in glacial varves from the Baltic Sea
Evidence of the final drainage of the Baltic Ice Lake and the brackish phase of the Yoldia Sea in glacial varves from the Baltic Sea
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波罗的海冰湖最终排水和约尔迪亚海咸水阶段来自波罗的海冰川的证据
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
E. Andrén
中科院分区：
文献类型：
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作者：
T. Andrén;G. Lindeberg;E. Andrén
根据波罗的海14个互相关的泥纹图和平均泥纹厚度曲线，建立了泥纹年代学。这个年表与瑞典时间表相关，涵盖了11530至10250年的时间跨度。通过数字颜色分析，对两个岩心的粒度、化学成分、硅藻含量和颜色变化进行了分析。波罗的海冰湖的最后一次排水可以追溯到c。10800年前，记录在分析的核心作为一个减少的粘土含量。该事件与大气Δ14C含量相关，可能导致11 565年至11 545年BP之间记录的这些值增加。波罗的海纹层年代学、格陵兰GRIP冰芯和大气Δ14C记录的对比结果表明，c.在瑞典时间表中，小于c的部分缺少760年。距今10250年。一个颜色的变化，从褐色到灰色的纹状冰川粘土记录c。10770年的BP被认为是缺氧的结果，由于沉积速率的增加，在早期Preboreal。第一个微咸的影响记录为c。10540年在波罗的海西北部和约90年后在哥特兰盆地东部的大规模BP。
A clay‐varve chronology based on 14 cross‐correlated varve graphs from the Baltic Sea and a mean varve thickness curve has been constructed. This chronology is correlated with the Swedish Time Scale and covers the time span 11 530 to 10250 varve years BP. Two cores have been analysed for grain size, chemistry, content of diatoms and changes in colour by digital colour analysis. The final drainage of the Baltic Ice Lake is dated to c. 10800 varve years BP and registered in the cores analysed as a decrease in the content of clay. This event can be correlated with atmospheric Δ14C content and might have resulted in an increase in these values recorded between 11 565 and 11 545 years BP. The results of the correlation between the varve chronology from the Baltic Sea, the Greenland GRIP ice core and the atmospheric Δ14C record indicate that c. 760 years are missing in the Swedish Time Scale in the part younger than c. 10250 varve years BP. A change in colour from a brownish to grey varved glacial clay recorded c. 10770 varve years BP is found to be the result of oxygen deficiency due to an increase in the rate of sedimentation in the early Preboreal. The first brackish influence is recorded c. 10540 varve years BP in the northwestern Baltic Sea and some 90 years later in the eastern Gotland Basin.