Abstract Terrestrial sedimentary archives that record environmental responses to climate over the last glacial cycle are underrepresented in subtropical Australia. Limited spatial and temporal palaeoenvironmental record coverage across large parts of eastern Australia contribute to uncertainty regarding the relationship between long-term climate change and palaeoecological turnover; including the extinction of Australian megafauna during the late Pleistocene. This study presents a new, high-resolution, calibrated geochemical record and numerical dating framework from Welsby Lagoon, a wetland from North Stradbroke Island that records key periods of late Pleistocene environmental change. Single-grain optically stimulated luminescence and radiocarbon dating are integrated into a Bayesian age-depth model for the sedimentary sequence spanning Marine Isotope Stage (MIS) 5 to the present. Scanning micro X-ray fluorescence (XRF) and bulk sediment XRF assays are used to infer past dust dynamics, with changes in the abundance of silica and potassium interpreted as proxies for aridity across local and regional sources. Variations in dust flux were contemporaneous with hydrological change, concordant with changes in vegetation cover on the island and, relate to deflation events at major dust source regions on the Australian continent. The Welsby Lagoon record supports the notion of a variable MIS4 within which an increased dust flux (71–67 ka), may be indicative of drier climate. Additionally, the record also shows a lower dust flux through the Last Glacial Maximum (LGM) than is evident in other Australian aeolian records. However, this low LGM flux is attributed to the wetland’s evolution, rather than a reduction in total dust flux.

中文翻译：

---

在过去 80,000 年中，从斯德布鲁克岛北部的韦尔斯比泻湖深入了解澳大利亚亚热带干旱

摘要 记录上次冰期循环对气候的环境响应的陆地沉积档案在澳大利亚亚热带地区代表性不足。澳大利亚东部大部分地区有限的空间和时间古环境记录覆盖范围导致长期气候变化与古生态周转之间关系的不确定性；包括更新世晚期澳大利亚巨型动物的灭绝。这项研究展示了来自 Welsby Lagoon 的新的、高分辨率、校准的地球化学记录和数值测年框架，Welsby Lagoon 是来自北斯德布鲁克岛的湿地，记录了晚更新世环境变化的关键时期。单粒光学受激发光和放射性碳测年被整合到贝叶斯年龄深度模型中，用于跨越海洋同位素阶段 (MIS) 5 到现在的沉积序列。扫描微 X 射线荧光 (XRF) 和大块沉积物 XRF 分析用于推断过去的尘埃动力学，将二氧化硅和钾丰度的变化解释为当地和区域来源干旱的代理。沙尘通量的变化与水文变化同时发生，与岛上植被覆盖的变化一致，并且与澳大利亚大陆主要沙尘源地区的紧缩事件有关。Welsby Lagoon 记录支持可变 MIS4 的概念，其中增加的灰尘通量 (71–67 ka) 可能表明气候干燥。此外，该记录还显示，通过末次盛冰期 (LGM) 的尘埃通量低于其他澳大利亚风成记录。然而，这种低 LGM 通量归因于湿地的演变，而不是总灰尘通量的减少。