RUI: Using the Products of Volcano-Ice Interaction to Constrain Paleo-ice Conditions II: Documenting Fluctuations in Continental Ice-sheets

RUI：利用火山-冰相互作用的产物来限制古冰条件 II：记录大陆冰盖的波动

• 批准号: 0910712
• 负责人: Benjamin Edwards
• 金额: $ 18.49万
• 依托单位: Dickinson College
• 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: 2009-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0910712&HistoricalAwards=false
• 关键词: RUI; Using; Products; Volcano; Ice

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." One of the greatest challenges for modern science is trying to predict the future implications of global climate change. While significant progress is being made towards understanding present-day controls on climate, in order to predict the direction of future climate change we must understand the Earth's climate cycle during the recent geological past. Information collected from the Earth's oceans and ice samples from Greenland and Antarctic ice help to understand changes in local and global temperature. However, much less information is available about how past temperature changes have affected snowfall and the formation of glaciers in North America. One of the most important records of continental climate in western North America is preserved within deposits formed by volcanic eruptions that occurred beneath snow and ice in northwestern British Columbia, Canada. This project will attempt to determine the eruption dates for several of those volcanoes in order to improve the on-land record of how continental climate, in northern latitudes, has responded to past changes in global temperature. Many of these volcanoes record the presence of ice during periods of the recent geological past when global temperatures were much cooler than today. Other volcanic deposits appear to have formed when no large ice masses were present; these deposits are also important as they document periods when continental climate may have been relatively warmer. Comparison of the continental record to the oceanic record will help scientists better make integrated global climate models.The goal of this project is to conduct a comprehensive field, geochemical and geochronological study of 34 basaltic glaciovolcanic and subaerial centers in the Tuya-Kawdy area in northern British Columbia, Canada, to determine if fluctuations in continental ice-sheet volumes affected the eruption frequencies and compositions of Pleistocene volcanism. The results of the proposed research will have important implications for two linked but separate scientific areas: (1) magma-ice dynamics and (2) Pleistocene paleoclimate. The proposed research will provide a detailed record of the presence, position and minimum thickness of the northern part of the Cordilleran ice sheet (CIS) throughout the Pleistocene. Glaciovolcanic deposits can survive erosion by multiple ice advances, and consequently are one of the few means of documenting the former presence of ice-bodies older than the Last Glacial Maximum (~30-20 ka); such deposits are crucial for investigating long-term responses of volcanism to ice fluctuations. Preliminary work in the Tuya-Kawdy area has already documented glaciovolcanic eruptions at ~700 ka and ~1.8 Ma. An expanded database will significantly improve our ability to understand how changes in Pleistocene climate, as recorded by marine proxies, correlate with the presence of continental ice sheets in northwestern North America. This study will be the most comprehensive to use glaciovolcanism to document the presence/absence of a major ice sheet in northwestern North America and attempt to correlate its fluctuations with the marine proxy ice-volume record. The results will give important constraints for understanding the terrestrial response to changes in ocean temperatures, ice sheet dynamics, biodiversity in deglaciated landscapes, and Pleistocene erosion rates.

“该裁决是根据2009年《美国复苏与再投资法》（公法111-5）资助的。”现代科学的最大挑战之一是试图预测全球气候变化的未来影响。尽管为了预测未来气候变化的方向，在理解当今的气候控制方面正在取得重大进展，但我们必须在最近的地质过去了解地球的气候周期。从地球海洋和来自格陵兰岛和南极冰的冰样收集的信息有助于了解局部和全球温度的变化。但是，关于过去温度变化如何影响降雪和北美冰川形成的信息要少得多。北美西部大陆气候的最重要记录之一保存在加拿大不列颠哥伦比亚省西北部的雪和冰下发生的火山喷发形成的矿床。该项目将试图确定其中几个火山的喷发日期，以改善北纬度地区大陆气候如何响应过去全球温度变化的陆地记录。这些火山中的许多人都记录了最近地质过去的冰期存在冰的存在，因为全球温度比今天凉爽得多。当不存在大冰块时，其他火山沉积物似乎已经形成。这些沉积物也很重要，因为它们记录了大陆气候可能相对温暖的时期。将大陆记录与海洋记录的比较将有助于科学家更好地建立整体的全球气候模型。该项目的目的是对北部Tuya-Kawdy地区的34个玄武岩冰川伏洛坎山脉和底部的34个玄武岩冰川中心进行全面的领域，地球化学和地球学研究。加拿大不列颠哥伦比亚省，以确定大陆冰盖量的波动是否影响更新世火山主义的喷发频率和组成。拟议研究的结果将对两个连接但独立的科学领域具有重要意义：（1）岩浆冰动力学和（2）更新世古气候。拟议的研究将详细记录整个更新世的山脉冰盖（CIS）北部的存在，位置和最小厚度。冰川岩矿可以通过多个冰的进展来生存，因此是记录以前存在的冰船比最后一次冰川最大值（〜30-20 ka）的少数手段之一；这种沉积对于研究火山对冰波动的长期反应至关重要。 Tuya-kawdy地区的初步工作已经记录了约700 ka和〜1.8 mA的冰川爆发。扩展的数据库将显着提高我们了解更新世气候变化的能力，如海洋代理所记录的那样，与北美西北部的大陆冰盖存在相关。这项研究将是最全面的，使用冰川洛克山主义记录北美西北部的主要冰盖的存在/不存在，并试图将其波动与海洋代理冰卷记录相关联。结果将为了解海洋温度变化，冰盖动态，脱落式景观的生物多样性和更新世侵蚀率的变化而产生重要的限制。