Rates, timing, & nature of sub-orbital sea-level change during MIS 5e

价格、时间、

• 批准号: 1559040
• 负责人: David Foster
• 金额: $ 50.39万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-15 至 2021-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1559040&HistoricalAwards=false
• 关键词: Rates; timing; & nature; sub

Projections for the magnitude and rate of sea-level change in the future are highly dependent on ice sheet models that simulate the response of the polar ice sheets to sustained warming. Unfortunately, the physics associated with ice sheet collapse is not fully understood, requiring a different approach to estimate future ice sheet response. This project seeks to quantify rates of sea-level change during a past warm period known as the last interglacial, ~125,000 years ago. This information can then be used to constrain our projections of the rate of future sea-level rise. In particular, the principal investigator will investigate the rate of sea-level changes during this past warm period associated with meter-scale sea-level oscillations. The oscillations have been inferred from the features observed in sedimentary records from around the globe that suggest a dynamic instability in polar ice sheets during the warm period. The project includes student training and education (Ph.D. and masters students, and undergraduate students). A marine science class from the University of Florida will go to a sampling site in southern Florida to gain valuable field experience. There is strong international collaboration between the principal investigator, U.S. students, and researchers from Mexico and Australia. Joint support for U.S. students to collaborate with researchers from Australia was provided by the Office of International Science and Engineering.This project will address existing debates regarding the timing and nature of sea-level oscillations during Marine Isotope Stage (MIS) 5e. The approach is to study several key fossil reef sequences around the globe using a multidisciplinary approach that combines detailed analysis of taphonomy, diagenesis, reef assemblages, paleowater depth indicators, carbonate sedimentology and petrography, stratigraphy, glacial isostatic adjustment, surveying, and geochemical and geochronological data. Conventional bulk U-Th analyses will be complemented with laser ablation U-Th ages to investigate micro-scale carbonate phases and to evaluate spatial scales of preservation within the samples.

对未来海平面变化幅度和速率的预估高度依赖于模拟极地冰盖对持续变暖的响应的冰盖模式。不幸的是，与冰盖崩塌相关的物理机制还没有被完全理解，这就需要一种不同的方法来估计未来冰盖的反应。该项目旨在量化约12.5万年前的最后一次间冰期（last interglacial），即过去一个温暖时期的海平面变化速率。这些信息可以用来限制我们对未来海平面上升速度的预测。特别是，首席研究员将调查过去暖期与米尺度海平面振荡相关的海平面变化速率。这些振荡是根据在全球各地的沉积记录中观察到的特征推断出来的，这些特征表明极地冰盖在温暖期存在动力不稳定。本项目包括学生的培养和教育（博士生、硕士生和本科生）。佛罗里达大学的一个海洋科学班将前往佛罗里达州南部的一个采样点，以获得宝贵的实地经验。主要研究者、美国学生以及来自墨西哥和澳大利亚的研究人员之间有强有力的国际合作。国际科学与工程办公室为美国学生与澳大利亚研究人员合作提供联合支持。该项目将解决关于海洋同位素阶段（MIS） 5e期间海平面振荡的时间和性质的现有争论。该方法是使用多学科方法研究全球几个关键的化石礁序列，该方法结合了埋藏学，成岩作用，礁组合，古水深指标，碳酸盐沉积学和岩石学，地层学，冰川均衡调整，测量以及地球化学和地质年代学数据的详细分析。传统的体积U-Th分析将与激光烧蚀U-Th年龄相补充，以研究微尺度碳酸盐相并评估样品内保存的空间尺度。