Quantifying subglacial erosion rates and exploring pro-glacial bedrock as climate archive by in-situ cosmogenic C-14 and Be-10 techniques

通过原位宇宙成因 C-14 和 Be-10 技术量化冰下侵蚀率并探索前冰川基岩作为气候档案

• 批准号: 0922165
• 负责人: Joerg Schaefer
• 金额: $ 18.7万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0922165&HistoricalAwards=false
• 关键词: Quantifying; subglacial; erosion; rates; exploring

A growing consensus believes that the number one environmental problem of our time is climate change and the evaluation of its consequences. Fundamental to predicting these effects is knowing whether the climate during the Holocene Epoch (the last 11,500 years), the period during which human civilization has developed, was perhaps even warmer than today. Glaciers are highly sensitive to climate changes and fluctuate considerably in response to small temperature excursions, such as the Little Ice Age. This project investigates the climate history of selected mountain glaciers that retreated substantally during recent years : Rhone Glacier, Switzerland, Nigardsbreen, Norway, and Franz-Josef-Glacier, New Zealand. Analysis of in-situ cosmogenic Be-10 and C-14 from bedrock surfaces in proximity to these glaciers will address whether, and for how long, these glaciers were smaller than today during the Holocene. The project will also yield quantitative data for glacier-bedrock interactions that can be directly fed into glacier-geomorphic landscape models. Human civilation has developed during the extraordinarily stable Holocene warm period, but climate variability has been large enough to impact rise and fall of ancient societies, illustrating the significance of climate change. However, the record of this change is poor. Glaciers are among the few elements of our environment sensitive enough to respond quickly to climate changes. The present episode of glacier retreat is exposing a large amount of bedrock, which can be used to determine the amount and timing of glacial recession . Cosmogenic isotopes from these bedrock surfaces provide information about when these surfaces were exposed by melting ice. The glacier fluctuation data will be coupled with ice-flow models to interpret them in view of realistic climatic scenarios. This project will add fundamental information to kowledge of subglacial erosion rates and Holocene warm periods, a key parameter in climate prediction models. Additionally, this study will assist in the evaluation of water availability in times of retreating glaciers and increasing population around the globe.

越来越多的共识认为，我们时代的头号环境问题是气候变化及其后果的评估。预测这些影响的基础是了解全新世时期（过去11,500年）的气候，人类文明发展的时期，也许比今天更温暖。冰川对气候变化高度敏感，并在小冰河时代等小的温度波动中波动很大。 该项目调查了近年来大幅度退缩的山区冰川的气候历史：瑞士的罗纳冰川，挪威的Nigardsbreen和新西兰的Franz-Josef冰川。对这些冰川附近基岩表面的原位宇宙成因Be-10和C-14的分析将解决这些冰川在全新世期间是否比今天小以及持续多久的问题。该项目还将产生冰川-基岩相互作用的定量数据，这些数据可以直接输入冰川-地貌景观模型。人类文明是在异常稳定的全新世温暖时期发展起来的，但气候变化已经大到足以影响古代社会的兴衰，说明了气候变化的重要性。然而，这种变化的记录很差。冰川是我们环境中为数不多的对气候变化足够敏感的元素之一。目前的冰川退缩事件暴露了大量的基岩，可以用来确定冰川退缩的数量和时间。来自这些基岩表面的宇宙成因同位素提供了这些表面何时被融化的冰暴露的信息。 冰川波动数据将与冰流模型相结合，以便根据现实的气候情景对其进行解释。该项目将为冰下侵蚀速率和全新世温暖期的知识增加基本信息，这是气候预测模型中的一个关键参数。此外，这项研究将有助于在冰川消退和地球仪人口增加的时期评估水的可用性。