The debate regarding the history of water‐level fluctuations in Lake Baikal extends back to the late 19th century and is rooted in the interpretation of the sequence of palaeo‐shoreline terraces observed around the Baikal trough. Modern studies identify terraces up to 200 m above and down to 40 m below the present‐day Lake Baikal water level, and opinions are split between (i) those who regard the lake‐level fluctuations as a function of shifts in water balance associated with glacial and interglacial periods, and (ii) those who attribute the changes to predominantly tectonic factors, permitting water‐balance fluctuations of not more than a few tens of metres. In either case, a definitive lake‐level scheme must also constrain the relative elevation of the Baikal's outlet, which has not been fixed over time. Here, we focus upon the lake‐level changes over the past 50 000 years with a new set of observations from an outstanding sequence of palaeo‐shoreline terraces on Bolshoi Ushkanii Island located in central Lake Baikal. By determining the ¹⁴C age of soils rapidly buried by beach deposits on two terraces, we provide direct evidence of lake‐level highstands at ~120–122 and ~72–83 m during Marine Isotope Stage (MIS) 3 (Karginsk interstadial). By integrating these results with the repeated subsidence of Baikal's outlet threshold since MIS 5e, we show that lake‐level fluctuations closely align with swings in glacial and interglacial climate.

中文翻译：

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莫斯科大乌什卡尼岛上古海岸线记录的MIS 3期间的贝加尔湖高水位

关于贝加尔湖水位波动历史的争论可以追溯到19世纪末，其根源在于对贝加尔湖海槽周围观察到的古海岸线阶地序列的解释。现代研究确定了当今贝加尔湖水位以上200 m和以下40 m以下的阶地，并且意见分歧（i）那些认为湖面波动是与之相关的水量平衡变化的函数的人冰川期和冰川间期，以及（ii）那些将变化归因于主要构造因素的时期，使得水平衡波动不超过几十米。在任何一种情况下，确定的湖平面方案还必须限制贝加尔湖出口的相对高度，该高度并未随着时间的推移而固定。这里，我们通过位于贝加尔湖中部的Bolshoi Ushkanii岛上一系列重要的古海岸线阶地的一系列新观测资料，着眼于过去50000年的湖面变化。通过确定¹⁴ C年龄的土壤被两个阶地的海滩沉积物迅速掩埋，我们提供了海洋同位素阶段（MIS）3（Karginsk interstadial）在约120–122和〜72–83 m的湖水位高位的直接证据。通过将这些结果与自MIS 5e以来贝加尔湖出水口阈值的反复沉陷相结合，我们表明湖泊水位的波动与冰川和冰川间气候的波动密切相关。