The Willandra Lakes region is a series of once interconnected and now-dry lake basins in the arid zone of southeastern Australia. It is a UNESCO World Heritage Site of cultural, archaeological, and geological significance, preserving records of Aboriginal occupation and environmental change stretching back to at least 50 ka. Linking the archaeology with the commensurate palaeoenvironmental information is complicated by the millennial time spans represented by the past hydrological record preserved in the sediment vs. the subdecadal evidence of each archaeological site. Oxygen isotope records across annual growth rings of fish otoliths (ear stones) can elucidate flooding and drying regimes on subannual scales. Otoliths from hearth sites (fireplaces) link lake hydrology with people eating fish on the lakeshore. Oxygen isotopic trends in hearth otoliths from the last glacial maximum (LGM) were previously interpreted in terms of high evaporation under dry conditions. However, this ignored hydrology-driven changes in water δ18O. Here, a mass balance model is constructed to test the effect lake desiccation has on water δ18O and how this compares with the LGM otolith records. Based on this modelling, we suggest that Lake Mungo otolith signatures are better explained by evaporation acting on full lakes rather than by lake drying.

中文翻译：

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澳大利亚蒙戈湖鱼耳石氧同位素组成的定量评估

威兰德拉湖区是澳大利亚东南部干旱地区的一系列曾经相互连接但现在已经干涸的湖盆。它是联合国教科文组织世界遗产，具有文化、考古和地质意义，保存了至少 50 ka 的土著职业和环境变化记录。由于沉积物中保存的过去水文记录与每个考古遗址的亚年代际证据所代表的千年时间跨度，将考古学与相应的古环境信息联系起来变得复杂。鱼耳石（耳石）年轮的氧同位素记录可以阐明次年尺度上的洪水和干燥状况。来自壁炉遗址（壁炉）的耳石将湖泊水文与在湖岸吃鱼的人们联系起来。上次盛冰期 (LGM) 的炉膛耳石中的氧同位素趋势以前被解释为干燥条件下的高蒸发量。然而，这忽略了水文驱动的水δ变化18O. 这里构建了一个质量平衡模型来测试湖泊干燥对水δ的影响18O 以及这与 LGM 耳石记录的比较。基于这个模型，我们建议通过蒸发作用在全湖上而不是通过湖干来更好地解释蒙戈湖耳石特征。