Collaborative Research: Resolving centennial- to millennial-scale trends in glacier extent and lake sedimentation in the Brooks Range, Arctic Alaska

该合作项目的目标是重建北极阿拉斯加的晚第四纪气候和冰川变化，阿拉斯加是北极少数几个山区冰川留下其以前范围的物理记录的地区之一，这对于比较低纬度和北极之间山区冰川变化的时间和程度是有价值的。布鲁克斯山脉的气候和冰川历史的几个特征与北大西洋地区的气候和冰川历史形成对比（在气候变化记录中，北大西洋地区通常被认为代表整个北方半球），目前可用的证据表明，布鲁克斯山脉的历史更接近南半球的冰川记录。研究人员建议从湖泊沉积物中记录气候变化，并使用冰前湖泊沉积物和冰川特征的铍-10年代测定来记录冰川波动，以解决围绕四个明显的全球变化间隔的问题：（1）末次冰期最大：在全球LGM期间，阿拉斯加北极的冰川退缩和温度升高，正如气候模型模拟的那样？(2)冰消期：在冰消期，阿拉斯加北极的气候变化在多大程度上与北大西洋的气候波动相吻合？(3)全新世冰川作用：在（a）全新世热高峰期和（B）新冰川作用期间，冰川的范围是什么？(4)小冰河时代：布鲁克斯山脉是更潮湿还是更干燥？这项研究将在北卡罗来纳州中部布鲁克斯山脉的合适山谷（有现存冰川的水上飞机可到达的山谷）进行。该项目有几个教育组成部分，包括支持四名研究生和几名本科生，并访问Anaktuvuk Pass社区，就气候研究和布鲁克斯山脉发表演讲。拟议的研究旨在产生美国最北端冰川地区冰川和气候变化的日期和定量记录北极冰川在晚冰期和全新世等温暖时期遭受极端气候事件时的过去行为可以提供有价值的见解，以帮助更好地预测对未来变化的反应。

The goal of this collaborative project to reconstruct late Quaternary climate and glacier change in Arctic Alaska, one of few regions in the Arctic where mountain glaciers have left physical records of their former extent, making it valuable for comparing the timing and extent of mountain glacier variability between the lower latitudes and the Arctic. Several features of the climate and glacier history of the Brooks Range contrast with those from the North Atlantic region (which is often taken to represent the entire Northern Hemisphere in records of climate change) and currently available evidence indicates that the history of the Brooks Range more closely resembles glacier records from the southern Hemisphere. The investigators propose to develop records of climate change from lake sediments and records of glacier fluctuations using proglacial lake sediments and beryllium-10 dating of glacial features to address questions centered around four intervals of pronounced global change: (1) Last Glacial Maximum: Did glaciers retreat and temperatures increase in Arctic Alaska during the global LGM, as has been simulated by climate models? (2) Deglaciation: To what extent did climate change in Arctic Alaska coincide with North Atlantic climate fluctuations during deglaciation? (3) Holocene Glaciation: What was the extent of glaciers during (a) the Holocene thermal maximum, and (b) Neoglaciation? (4) Little Ice Age: Was it wetter or drier in the Brooks Range? The research will take place in suitable valleys (floatplane accessible valley with extant glaciers) in the north­central Brooks Range. The project has several educational components, including support four graduate students and several undergraduate students and visits to the community of Anaktuvuk Pass to deliver presentations on climate research and the Brooks Range. The proposed research aims to produce well-dated and quantitative records of glacier and climate variability in the northernmost glaciated region of the U.S. Documenting the past behavior of arctic glaciers when subject to extreme climate events during the late glacial period and warm intervals like the Holocene can provide valuable insight to help better predict responses to future change.