Collaborative Research: Paleo Records Of GLacier And Climate changes Inferred from Alaskan Lakes (PROGLACIAL)

合作研究：从阿拉斯加湖泊推断的冰川和气候变化的古记录（PROGLACIAL）

• 批准号: 2303462
• 负责人: Darrell Kaufman
• 金额: $ 49.66万
• 依托单位: Northern Arizona University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303462&HistoricalAwards=false
• 关键词: Collaborative; Research; Paleo; Records; GLacier

Climate change poses a major challenge for society. More information is needed to put recent climate changes into a long-term context of natural climate variability. This information helps to foresee possible future climate trends, especially those that involve slow-moving features of the climate system, which will continue to change over hundreds to thousands of years to come. A variety of geological evidence can be used to extend observations of temperature and other climate variables back in time. This project focuses on reconstructing glacier fluctuations in Alaska, the Arctic region of the United States, as evidence for past climate changes extending back for thousands of years. The research team will estimate past glacier size by studying sediment from glaciers that is carried by meltwater streams and deposited in glacier-fed lakes. The sediment samples collected for this project will also be studied for signs of earthquakes and volcanic eruptions to determine how frequently these damaging events have occurred in the past and will likely occur in the future. The project will also help prepare undergraduate and graduate students for careers in the STEM workforce.The extent of glacier cover is a prime indicator of climate. Sediments stored in glacier-fed (proglacial) lakes provide a uniquely continuous record of glacier-size fluctuations. This project will further develop the ability to reconstruct the extent of glacier cover within the catchment of proglacial lakes using basic sedimentary indicators of glacier rock-flour abundance (bulk density, organic matter, particle size, magnetic susceptibility, and accumulation rate). By sampling proglacial lakes along an environmental gradient of heavily to sparsely glaciated catchments in Alaska, the research team will systematically acquire quantitative information about these well-known glacial indicators, which vary with glacier size and other environmental variables. This information will be used to develop a numerical model to estimate past glacier extent based on lake sediment properties measured in sediment cores taken from multiple lakes in south-central and northwest Alaska that extend back to around 15,000 years. In addition to rock-flour indicators, the sediment will be analyzed for terrestrial and aquatic productivity indicators, including organic pigments and biogenic silica abundance, which are amenable to generating time series with decadal-scale resolution. These records will be used to address fundamental questions related to the timing and extent of climate changes in Alaska that occurred following the last major ice age. The ages of the lake sediment will be determined using short-lived radioisotopes, volcanic ash layers, and radiocarbon dating. This project will also contribute to assessing geological hazards related to seismic and volcanic activity near the most populated area of Alaska, supporting and engaging STEM graduate and undergraduate students and early career researchers, and developing scientific resources, including the popular Alaska PaleoGlacier Atlas.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.

气候变化对社会构成了重大挑战。需要更多信息将最近的气候变化置于自然气候变化的长期背景下。这些信息有助于预见未来可能的气候趋势，尤其是那些涉及气候系统缓慢移动特征的趋势，这些趋势将继续变化数百万到几千年。可以使用多种地质证据来扩展温度和其他气候变量的观察结果。该项目的重点是重建美国北极地区阿拉斯加的冰川波动，作为过去数千年延长的过去气候变化的证据。研究小组将通过研究冰川流携带并沉积在冰川喂养的湖泊中的冰川的沉积物来估计过去的冰川大小。还将研究为该项目收集的沉积物样品，以确定这些破坏性事件过去发生的频率，并且将来可能会发生。该项目还将有助于为STEM员工职业的本科生和研究生做好准备。冰川覆盖的程度是气候的主要指标。存储在冰川喂养的（前冰）湖泊中的沉积物提供了冰川大小波动的独特连续记录。该项目将进一步发展能够使用冰川岩石丰度的基本沉积指标（散装密度，有机物，有机物，粒径，磁化率和累积速率）重建冰期湖泊集水区域内冰川覆盖率的能力。通过对阿拉斯加的重大冰川裂开的环境梯度进行采样，研究团队将系统地获取有关这些众所周知的冰川指标的定量信息，这些信息随冰口大小和其他环境变量而变化。该信息将用于开发一个数值模型，以根据从阿拉斯加中南部和西北部的多个湖泊中测得的湖泊沉积物特性估算过去的冰川范围，从而延伸至约15，000年。除了岩石指标外，还将分析沉积物的陆地和水生生产率指标，包括有机色素和生物二氧化硅丰度，这些指标可容纳具有衰老规模分辨率的时间序列。这些记录将用于解决与最后一次主要冰河时代发生在阿拉斯加气候变化的时机和程度有关的基本问题。湖泊沉积物的年龄将使用短寿命的放射性同位素，火山灰层和放射性碳年代确定。该项目还将有助于评估与阿拉斯加人口最多的地震和火山活动相关的地质危害，支持和吸引STEM毕业生和本科生以及早期职业研究人员以及开发科学资源，包括流行的阿拉斯加古流媒体，包括NSF的法规及其范围，这是NSF的法规及其范围的支持。 标准。