Collaborative Research: RUI: Tropical Holocene climatic insights from Andean paleoglacier dynamics

合作研究：RUI：安第斯古冰川动力学对热带全新世气候的见解

• 批准号: 1344476
• 负责人: Nathan Stansell
• 金额: $ 3.83万
• 依托单位: Northern Illinois University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1344476&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Tropical; Holocene

This grant supports research generating continuous, centennial to millennial-scale records of mountain glaciation in Peru spanning the Holocene (~12 ka to present) that tests hypotheses concerning the causes of abrupt climate change in the tropics. Radiocarbon and 210Pb dating of glacial flour flux provides precise ages of Holocene ice advances/retreats and records of abrupt climatic transitions, using proglacial lake sediment cores from multiple lakes along the steep East-West moisture gradient across the central Peruvian Andes. The flux of glacial flour is determined based on multiple proxies at a resolution sufficient to enable comparison with existing stable isotope records of paleoclimate variability from the region. Previous work in the tropical Andes demonstrates that the glacial-flour approach can provide a record of glaciation that is both consistent with and far more continuous than radiometrically-dated moraine records. This approach has the potential to resolve several glacial geologic uncertainties, such as the timing of early Holocene glacial advances, and the possible time-transgressive nature of ice margin fluctuations during the neoglacial. The glacial-lacustrine approach is coupled with detailed moraine mapping and the targeted application of cosmogenic radionuclide dating to select Holocene moraines located up-valley from coring localities. The strategic pairing of glacial flour records with dated moraines provides both the timing and magnitude of ice margin changes. Inverse glacier mass balance-ice flow simulations from multiple watersheds in different precipitation regimes provide validation for the dynamical down-scaling of global-scale circulation and paleoclimate models.Intellectual Merits and Broader Impacts: Relating the changes in tropical glacier mass to climate dynamics is a priority for global climate modeling efforts to predict future changes based on accurately simulating past changes under different greenhouse scenarios. The long-term perspective of temperature and precipitation changes on tropical glacier mass and energy balance is still poorly understood, primarily because of a lack of detailed and continuous glacial records from both the humid and more arid parts of the tropical Andes. This work substantially improves our understanding of the link between alpine glacial variability, water resources and mass and energy fluxes in the tropical "heat engine" of the planet.These records are needed to better understand the timing, magnitude, and spatial extent of high elevation (5000 - 6000 masl) tropical atmospheric change during the Holocene to evaluate the role of the low latitude hydrologic cycle in abrupt global climatic shifts. This, in turn, will enable testing of the following hypotheses:(1) Glacier margin fluctuations in the tropical Andes during the Holocene were driven by changes in the strength of the South American Summer Monsoon(2) A broad regional pattern of Holocene glacial variability was punctuated by periods of rapid ice advances every ~1000 to 1500 years(3) Abrupt (centennial to millennial-scale) Holocene glacier variations in the southern tropics were nearly synchronous with those in the Northern Hemisphere (i.e. The Little Ice Age)

这项赠款支持研究涉及全新世（〜12 ka）的千禧年冰川山冰期记录的持续，百年纪念的研究，该记录测试了关于热带气候突然气候变化的原因的假设。放射性碳和210pb的冰川面粉通量的年代可提供全新世冰的精确年龄，并使用沿着秘鲁中部中部陡峭的东西方湿度梯度的多个湖泊的前冰湖沉积物核心进行了前进的气候过渡的记录。冰川粉的通量是基于多个代理，该分辨率足以与现有的稳定同位素记录进行比较。热带安第斯山脉（Andes）的先前工作表明，冰川 - 弗洛（Glacial-Folour）方法可以提供冰川记录，这既与放射性年代的冰ora记录都相比和更连续。这种方法有潜力解决几种冰川地质不确定性，例如早期冰川发展的时机，以及新缝线期间冰缘波动的可能时间转换性质。冰川 - 河流方法与详细的冰or式映射以及宇宙源性放射性核素约会的有针对性应用在选择位于加油区域的上谷的全新世莫兰氏菌。冰川粉记录与过时的冰fat式配对提供了冰缘变化的时机和幅度。来自不同降水状态下多个流域的倒数冰川质量平衡冰冰模拟模拟为全球尺度循环和古气候模型的动态下缩放提供了验证。智慧优点和更广泛的影响：将热带冰川质量的变化与气候变化与气候模型的优先范围相关联，以预测未来的模拟场景的优先范围。热带冰川质量和能量平衡的温度和降水变化的长期视角仍然很少了解，这主要是由于缺乏来自热带安第斯山脉的潮湿和干旱部分的详细和连续冰川记录。这项工作大大提高了我们对阿尔卑斯河冰川变异性，水资源以及质量和能量通量之间的联系，地球的热带“热发动机”。需要这些记录来更好地了解高升高（5000-6000 MASL）在整个整个过程中的热带大气变化的高度高度的时间，高度和空间范围，以评估低量级的综合量。反过来，这将实现以下假设的测试：（1）在全新世期间，热带安第斯山脉的冰川边缘波动受到南美夏季季风的强度的变化（2）全新世冰川变化的广泛区域模式的驱动。南部热带地区的变化与北半球的变化几乎是同步的（即小冰河时代）