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

对未来海平面变化幅度和速度的预测在很大程度上取决于模拟极地冰盖对持续变暖的反应的冰盖模型。不幸的是，与冰盖崩塌相关的物理学还没有完全理解，需要一种不同的方法来估计未来的冰盖响应。这个项目试图量化海平面在过去温暖时期的变化速度，这段时期被称为最后一次间冰期，大约在12.5万年前。然后，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，首席调查员将调查过去暖期内与米级海平面振荡有关的海平面变化率。这些振荡是从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暖期存在动态不稳定。该项目包括学生培训和教育(博士和硕士学生，以及本科生)。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，以获得宝贵的野外经验。首席研究人员、美国学生以及来自墨西哥和澳大利亚的研究人员之间有很强的国际合作。国际科学与工程办公室为美国学生与澳大利亚研究人员的合作提供了联合支持。这个项目将解决目前关于海洋同位素阶段5E期间海平面波动的时间和性质的争论。这种方法是利用多学科方法研究全球几个关键的化石生物礁序列，该方法结合了对挖掘学、成岩作用、生物礁组合、古水深度指示器、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。常规的整体U-Th分析将与激光消融U-Th年龄相补充，以研究微尺度的碳酸盐相并评估样品中保存的空间尺度。

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.