Defining and Modeling the Response of a Low Gradient Coastal System to Rapid Sea-Level Rise during the Late Pleistocene

在过去的120年里，海平面上升的速度已经加速，从19世纪的全球上升速度大约为零，到20世纪的平均速度大约为1.7毫米/年，再到目前的3.4 +/- 0.4毫米/年。13万至8万年前对海平面高水位标记的地质观测表明，全球海平面在几千年的时间里达到了大约+2米的高度（相对于现代海平面），随后可能迅速上升到大约+6米。这项提案的目标是确定北卡罗来纳州和弗吉尼亚州的海岸在这段时间内对海平面变化的反应。该项目将收集北卡罗莱纳州和弗吉尼亚州地区的地球物理数据和沉积物岩心。这些沉积物包含了海平面快速上升期间发生的侵蚀和沉积造成的过去变化的记录，可以为该地区未来的情况提供模拟。该项目为研究生和本科生提供培训。本研究旨在了解低梯度海岸系统对海平面上升的地质和形态动力学响应。在北卡罗莱纳东部和维吉尼亚州，晚更新世海侵至高水位沉积出现在沿海平原的海洋同位素第5阶段古海岸线向海方向和现代河口下方。地球物理数据和沉积物岩心将在该地区的两个研究区收集。这些数据将在未来用于开发该地区相关系和层序地层格架的3D模型，开发数值水动力模型以了解沿海系统对海平面快速上升的响应，并对更新世海平面进行垂直约束。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Rates of sea-level rise have accelerated over the last 120 years, from global rates of approximately zero in the 19th century, to an average rate in the 20th century of approximately 1.7 mm/y, to the present rate of 3.4 +/- 0.4 mm/y. Geologic observations of sea-level high-stand markers from 130,000 to 80,000 years ago suggest that global sea level attained a height of approximately +2 m (relative to modern sea level) for several millennia, possibly followed by a rapid rise to approximately +6 m. The goal of this proposal is to determine how the coasts of North Carolina and Virginia responded to sea level changes during these times. This project will collect geophysical data and sediment cores in the North Carolina and Virginia region. The deposits contain a record of past changes due to erosion and sedimentation that occurred during rapid sea level rise that could provide an analog for future conditions in this region. The project provides training for graduate and undergraduate students. This proposal will address the objective of understanding the geological and morphodynamic response of a low-gradient coastal system to sea-level rise. In eastern North Carolina and Virginia, late Pleistocene transgressive to high-stand deposits occur seaward of the Marine Isotope Stage 5 paleoshoreline on the coastal plain and beneath the modern estuaries. Geophysical data and sediment cores will be collected in two study areas in the region. These data will be used in the future to develop a 3D model of facies relationships and the sequence stratigraphic framework of the region, to develop numerical hydrodynamic models to understand the response of the coastal system to rapid sea level rise, and to place vertical constraints on Pleistocene sea levels.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.