Abandoned shorelines are an important archive used to constrain past fluctuations in the hydrological balance of lakes around the globe. Within Australia, the shorelines preserved at Lake George, NSW, form one of the few shoreline archives in the south-east of the continent that record palaeoenvironmental conditions throughout the late Quaternary. Here, we examined and tested the lake-level record for Lake George constructed in the 1970s by dating a well-preserved shoreline sequence at Luckdale, on the lake's eastern shore, using single-grain optically stimulated luminescence (OSL) dating. Ten stratigraphic units were identified, and these suggest a late Quaternary highstand for Lake George in MIS 3, with fluctuations superimposed upon an overall drying trend throughout MIS 2 and into the present. At Luckdale, the highest four shoreline-associated units were deposited ~13 to 19 m above lake base and date to between 39 ± 2 and 29 ± 1 ka ago. Our study pushes back the timing of maximum lake depth at Lake George to at least MIS 3, rather than MIS 2. The overall drying trend is supported by similar reductions in both Riverine Plain fluvial activity and other associated lake-level records from within the Murray basin.

中文翻译：

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重访澳大利亚乔治湖废弃的海岸线：一个精致的光学测年框架

废弃的海岸线是一个重要的档案，用于限制全球湖泊水文平衡的过去波动。在澳大利亚境内，保存在新南威尔士州乔治湖的海岸线是该大陆东南部为数不多的记录了整个晚第四纪古环境条件的海岸线档案之一。在这里，我们通过使用单晶粒光受激发光 (OSL) 测年法对位于该湖东岸 Luckdale 的保存完好的海岸线序列进行测年，检查并测试了 1970 年代建造的乔治湖的湖水位记录。确定了 10 个地层单元，这些表明 MIS 3 中乔治湖的晚第四纪高位，波动叠加在整个 MIS 2 和到现在的整体干燥趋势上。在拉克代尔，最高的四个海岸线相关单元沉积在湖底上方约 13 至 19 m 处，日期为 39 ± 2 至 29 ± 1 ka 之前。我们的研究将乔治湖最大湖泊深度的时间推迟到至少 MIS 3，而不是 MIS 2。整体干燥趋势得到了河流平原河流活动和默里内部其他相关湖泊水位记录的类似减少的支持盆地。