Constraining drought records in the central Great Plains (USA) within the last 1,500 years using innovative luminescence-dating methods

干旱是美国大平原中部和南部最重大的自然威胁之一。大平原干旱和相关沙丘活动阶段的准确和精确的年表对于了解这些自然灾害的频率和严重程度至关重要。除了有关时间和规模的历史记录外，干旱只能从沉积物档案中揭示出来。由于大平原中部和西南部(科罗拉多州、内布拉斯加州、堪萨斯州)湖泊或其他沉积汇的丰度有限，风沙(沙)沙丘及其干旱引起的重新激活有望提供有关过去几个世纪严重干旱阶段的最有价值的信息。Constrain的目标是对过去1500年来大平原西南部的史前干旱进行新的、准确的和精确的时间定位。在该项目中，我们的目标是(1)开发一种常规的发光测年技术，使用锆石来限制短时间尺度(长达1,500年)的地貌过程，具有理想的年度精度；(2)使用高分辨率的年代学模型和新的统计方法，生成大平原南部史前沙丘活动的高分辨率景观模型。在全球气候变暖的背景下，这些成果有望有助于预测和有效减轻研究区未来的干旱灾害。该项目是海德堡大学(德国)、洛桑大学(瑞士)和内布拉斯加-林肯大学(美国)的合作项目。该项目设计为试验性研究，将主要侧重于筹备工作，展示锆石测年方法的可行性，并建立研究伙伴关系。

Droughts are amongst the most significant natural threats in the central and southern Great Plains (USA). Accurate and precise chronologies of droughts and related dune activity phases in the Great Plains are paramount for understanding the frequency and magnitude of these natural disasters. Beyond historical records on the timing and magnitude, droughts can be revealed only from sediment archives. Due to the limited abundance of lakes or other sedimentary sinks in the central and southwestern Great Plains (Colorado, Nebraska, Kansas), aeolian (sand) dunes and their drought-induced re-activation are expected to provide the most valuable information on severe phases of aridity during the past centuries. CONSTRAIN aims at a new, accurate and precise temporal placement of pre-historic droughts in the southwestern Great Plains over the last 1,500 years. Within the project, we aim at (1) developing a routine luminescence dating technique using zircons to constrain geomorphological processes on short times scales (up to 1,500 years) with ideally annual precision, (2) generating a high-resolution landscape model of pre-historic dune activity in the southern Great Plains using a high-resolution chronological model and new statistical approaches. Against the background of global warming, these results are expected to contribute to predicting and effectively mitigating future drought hazards in the study area. The project is a collaboration of Heidelberg University (Germany), Université de Lausanne (Switzerland) and the University of Nebraska–Lincoln (USA). The project is designed as a pilot study and will mainly focus on preparatory work, showing the feasibility of the zircon dating approach and establishing the research partnership.