CAREER: A Model-Based Rosetta Stone to Decipher the Stratigraphic Expression of Glacial Isostasy

海平面上升将是气候变暖对社会最严重的影响之一。为了评估极地冰盖和海平面变化对温度升高的敏感性，该职业奖研究了浅层海底沉积物的积累如何记录海平面的变化。随着冰盖的融化，地球表面可以预见地随着冰盖重量的减少而弯曲，而海水则淹没了大陆边缘。如果融化的水像浴缸一样均匀地填满世界的海洋，这种弯曲会导致当地海平面的变化不同于预测的上升。由于冰盖融化导致的海平面上升在全球范围内会有所不同，一些沉积物档案比其他档案更准确地记录了海平面的变化。这项研究将使用计算机模型绘制过去两个地质时代海平面变化差异的全球地图，这两个地质时代的温度高于21世纪的预测。这样的地图将澄清地质情况，地质学家可以利用全球沉积物档案中明显不同的海平面变化幅度，更准确地重建过去冰盖融化的位置和规模。该项目通过创建一个“罗塞塔石碑”来解码过去温暖时期沿海地质中保留的古代海平面变化幅度，从而改进未来的海平面预测，从而促进了对气候的理解。综合教育计划将编制关于海平面变化的科学和伦理的新课程，以激励大学生参与日益增多的解决海平面预测和减缓问题的工作队伍。该教育计划将邀请非stem本科生创作和传播艺术推广产品，向公众解释海平面变化的地理差异。固体地球物理学家和第四纪地层学家之间的合作表明，冰川均衡调整（GIA）同时创造和破坏了调节，因此冰川-间冰期旋回的地层记录应该在不同的地方出现不同；反过来，从地层档案中推断出的同时期当地海平面的空间差异应该提供对消冰作用的大小和融化源的深入了解。本提案采用数值GIA模拟，对上新世中期暖期和渐新世南极冰盖开始的文献提出的震级和融化源进行“指纹”，以“识别”冰川沉降的空间偏差。然后，这些空间变化的海平面记录将作为一个软件的输入，该软件模拟沉积和沉降如何调节GIA在地层学中的表现。结果将有助于解码适用于整个地质时间尺度的冰河时代地层学中保留的海平面空间模式。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。

Rising sea levels will be among the most severe impacts of a warming climate on society. To assess the sensitivity of polar ice caps and sea-level change to increase in temperatures, this CAREER award examines how sediments accumulating on the shallow seafloor archive sea-level change. As ice sheets melt, the earth’s surface bends predictably in response to the shrinking weight of the ice sheets and ocean waters flooding continent edges. This bending causes local sea-level change to differ from the rise predicted if melt water evenly filled the world’s oceans, like a bathtub. The sea-level rise in response to a melting ice sheet will differ across the globe, with some sediment archives retaining a more accurate measure of sea-level change than others. This research will use computer models to make global maps of differences in sea-level change for two past geological epochs with temperatures higher than 21st century projections. Such maps will clarify the circumstances for which geologists can leverage the apparently different magnitudes of sea-level change from sediment archives around the globe to provide more accurate reconstructions of past ice sheet melt location and scale. This project advances climate understanding by creating a ‘Rosetta Stone’ to decode the magnitude of ancient sea-level change retained in coastal geology of past warm periods so as to refine future sea level projections. The integrated education plan will generate novel curriculum on the science and ethics of sea-level change to inspire university students to participate in a growing workforce addressing sea level projection and mitigation. The education plan will engage non-STEM undergraduates to create and disseminate artistic outreach products explaining geographic differences in sea-level change to the public.Collaboration between solid earth geophysicists and Quaternary stratigraphers has revealed that glacial isostatic adjustment (GIA) concurrently creates and destroys accommodation, such that the stratigraphic record of glacial–interglacial cycles should appear different from place to place; in turn spatial differences in contemporaneous local sea level deduced from the stratigraphic archive should provide insight into the magnitude and melt source of a deglaciation. This proposal undertakes numerical GIA simulations to ‘fingerprint’ spatial deviations from glacioeustasy for literature-proposed magnitudes and melt sources for the mid-Pliocene warm period and the Oligocene inception of the Antarctic ice sheet. These spatially variable sea-level records will then serve as inputs into a software that models how sedimentation and subsidence modulate how GIA manifests in stratigraphy. The results will serve to decode spatial patterns in sea level retained in ice-age stratigraphy applicable across the geological timescale.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.