EAGER: Testing Late-Pleistocene and Holocene Climate Change in Southeastern Australia with Multi-proxy Analyses of Alpine Lake Sediments, Kosciuszko National Park, Australia

该项目的资助下，EARLY概念补助金的探索性研究（EAGER）奖的概念的主持下，测试晚更新世通过晚全新世气候变化的想法在澳大利亚东南部的基础上，从三个高山tarns（湖泊）在雪山，新南威尔士州，澳大利亚的最高部分收集的沉积物岩心的多重代理分析。 尽管最近努力重建南半球主要冰后期气候事件的规模和空间分布（例如，南极气候恢复，小冰期），代理数据的关键差距，特别是在澳大利亚，阻碍了这些重建;这个差距反映了大陆上缺乏保存高分辨率，连续的古气候记录的网站。在新南威尔士州的Kosciuszko国家公园（KNP）的高山湖泊是这个问题的显著例外：自18，000 - 20，000年前冰川消退以来，有五个湖泊一直充当着连续的沉积物陷阱。蓝湖在20世纪70年代曾被取过芯，尽管对这些芯的分析有限，但它们表明，自冰川消退（18,000年前）以来，蓝湖一直在捕获沉积物。在西华盛顿大学（WWU）的一笔小额赠款下，研究人员于2016年从湖中收集了一个试点核心，以测试从湖中收集连续记录的可行性。 在ITRAX多扫描仪上对岩心进行的初步分析表明，沉积物保存完好，结构高度规整。视觉和X射线图像都显示整个核心的亚厘米级地层;根据上面的年龄估计，这种地层学将提供亚百年分辨率（约100年）。20年/cm）。如果通过年代测定得到证实，这种分辨率在澳大利亚南部将是前所未有的。这一单一的岩心证明了蓝湖单独保存的特殊地层记录，并意味着公园内其他较小的焦油湖可能存在类似的互补记录。为了测试这一点，研究人员建议在公园中增加两个焦油湖：阿尔宾纳湖和俱乐部湖;虽然比蓝湖浅，但两者都占据基岩盆地，因此比沉积物阻塞的湖泊更不容易受到与干旱有关的湖泊水位波动的影响。它们不同的大小、深度和盆地几何形状可能为蓝湖提供补充记录，使研究人员能够根据岩心的相关性测试区分本地和区域信号。坎特伯雷大学将进行一系列分析，以测试这些湖泊岩心的古气候潜力。更广泛的影响包括提供新的数据和见解，了解过去可能发生的干旱和温度变化的频率和程度，并向当地的资源管理人员提供信息。机构和水和电力公用事业公司。该项目还将为早期职业科学家、本科生和研究生提供有价值的培训。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

This project is funded, under the auspices of the EArly Concept Grant For Exploratory Research (EAGER) award concept, to test ideas on late-Pleistocene through late-Holocene climate change in southeastern Australia based on multiproxy analyses of sediment cores collected from three alpine tarns (lakes) in the highest portions of the Snowy Mountains, New South Wales, Australia. Despite recent efforts to reconstruct the magnitude and spatial distribution of major post-glacial climate events in the Southern Hemisphere (e.g., Antarctic Climate Reversal, Little Ice Age), key gaps in proxy data, most notably in Australia, hinder these reconstructions; this gap reflects a dearth of sites on the continent that preserve high resolution, continuous paleoclimate records. The alpine tarns in Kosciuszko National Park (KNP), New South Wales, represent notable exceptions to this problem: five tarns have acted as continuous sediment traps since deglaciation 18,000-20,000 years agoAll lakes in KNP freeze during the peak of the Austral winter (July-September), which provides stable surfaces for deep coring. Blue Lake was previously cored in the 1970’s, and although analyses of those cores were limited, they indicated that the lake has trapped sediment continuously since deglaciation (18,000 years ago). With a small grant from Western Washington University (WWU), the researchers collected a pilot core from the lake in 2016 in order to test the viability of collecting continuous records from the lake. Initial analysis of the core on an ITRAX multi-scanner demonstrates that the sediments are well preserved and highly structured. Both visual and X-ray imagery indicate sub-centimeter scale strata throughout the core; based on the age estimates from above, this stratigraphy would provide sub-centennial resolution (ca. 20 year/cm) throughout the core. If borne out by dating, such resolution would be unprecedented in southern Australia.This single core demonstrates the exceptional stratigraphic record preserved in Blue Lake alone, and implies that similar, complementary records likely exist in the other, smaller tarns in the park. To test this, the researchers propose to core two additional tarns in the park: Lake Albina, and Club Lake; although shallower than Blue Lake, both occupy bedrock basins and so are less susceptible to lake-level fluctuations related to droughts than sediment dammed lakes. Their differing sizes, depths, and basin geometries might provide complementary records to Blue Lake, allowing the researchers to distinguish between local and regional signals based on correlation testing of the cores.In addition to collecting cores, a suite of analyses to test the paleoclimate potential of cores from these lakes will be conducted at University of Canterbury/University of Queensland by Australian collaborators under existing Australian funding.The Broader Impacts include providing new data and insights into the frequency and magnitude of possible past droughts and temperature variations as well as informing resource managers in local agencies and water and power utility companies. The project will also provide valuable training of early career scientists and undergraduates and graduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.