Collaborative Research: Resolving Earth Structure Influence on Ice-Sheet Stability in the Wilkes Subglacial Basin (RESISSt)

合作研究：解决地球结构对威尔克斯冰下盆地冰盖稳定性的影响 (RESISSt)

• 批准号: 1914743
• 负责人: Thorsten Becker
• 金额: $ 11.5万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1914743&HistoricalAwards=false
• 关键词: Collaborative; Research; Resolving; Earth; Structure

Part I: NontechnicalEarths warming climate has the potential to drive widespread collapse of glaciers and ice sheets across the planet, driving global sea-level rise. Understanding both the rate and magnitude of such changes is essential for predicting future sea-level and how it will impact infrastructure and property. Collapse of the ice sheets of Antarctica has the potential to raise global sea-level by up to 60 meters. However, not all regions of Antarctica are equally suspectable to collapse. One area with potential for collapse is the Wilkes Subglacial Basin in East Antarctica, a region twice the size of California's Central Valley. Geologic evidence indicates that the ice-sheet in this region has retreated significantly in response to past global warming events. While the geologic record clearly indicates ice-sheets in this area are vulnerable, the rate and magnitude of any future retreat will be influenced significantly by geology of the region. In particular, ice-sheets sitting above warm Earth will collapse more quickly during warming climate. Constraining the geologic controls on the stability of the ice-sheets of the Wilkes Subglacial Basin remains challenging since the ice-sheet hides the geology beneath kilometers of ice. As a step in understanding the potential for future ice loss in the Wilkes Subglacial Basin this project will conduct geophysical analysis of existing data to better constrain the geology of the region. These results will constrain new models designed to understand the tectonics that control the behavior of the ice-sheets in the region. These new models will highlight the geological properties that exert the most significant control on the future of the ice-sheets of the Wilkes Subglacial Basin. Such insights are critical to guide future efforts aimed at collecting in-situ observations needed to more fully constrain Antarctica's potential for future sea-level. Part II: Technical DescriptionIn polar environments, inward-sloping marine basins are susceptible to an effect known as the marine ice-sheet instability (MISI): run-away ice stream drainage caused by warm ocean water eroding the ice shelf from below. The magnitude and time-scale of the ice-sheet response strongly depend on the physical conditions along the ice-bed interface, which are, to a first order, controlled by the tectonic evolution of the basin. Topography, sedimentology, geothermal heat flux, and mantle viscosity all play critical roles in ice-sheet stability. However, in most cases, these solid-Earth parameters for regions susceptible to the MISI are largely unknown. One region with potential susceptibility to MISI is the Wilkes Subglacial Basin of East Antarctica. The project will provide an integrated investigation of the Wilkes Subglacial Basin, combining geophysical analyses with both mantle flow and ice-sheet modeling to understand the stability of the ice sheet in this region, and the associated potential sea level rise. The work will be focused on four primary objectives: (1) to develop an improved tectonic model for the region based on existing seismic observations as well as existing geophysical and geological data; (2) to use the new tectonic model and seismic data to estimate the thermal, density, and viscosity structure of the upper mantle and to develop a heat flow map for the WSB; (3) to simulate mantle flow and to assess paleotopography based on our density and viscosity constraints; and (4) to assess ice-sheet behavior by modeling (a) past ice-sheet stability using our paleotopography estimates and (b) future ice-sheet stability using our heat flow and mantle viscosity estimates. Ultimately, the project will generate improved images of the geophysical structure beneath the WSB that will allow us to assess the geodynamic origin for this region and to assess the influence of geologic parameters on past, current, and future ice-sheet behavior. These efforts will then highlight areas and geophysical properties that should be the focus of future geophysical deployments.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.

第一部分：非技术性的变暖气候有可能使冰川和冰盖在整个地球上广泛崩溃，推动全球海平面上升。了解这种变化的速度和幅度对于预测未来的海平面及其将如何影响基础设施和财产至关重要。南极洲冰片的崩溃有可能提高全球海平面高达60米。但是，并非所有南极地区的所有区域都同样怀疑崩溃。一个有潜力崩溃的区域是南极洲东部的威尔克斯亚冰河盆地，这是加利福尼亚州中部山谷的两倍。地质证据表明，该地区的冰盖已响应过去的全球变暖事件而显着撤退。尽管地质记录清楚地表明该地区的冰盖很脆弱，但任何未来撤退的速度和幅度都将受到该地区地质的显着影响。特别是，在温暖的气候下，坐在温暖地球上方的冰盖将更快地崩溃。将地质控制限制在威尔克斯亚冰川盆地冰盖的稳定性上，因为冰淇淋将地质藏在冰公里以下，因此仍然具有挑战性。为了理解威尔克斯亚冰河盆地未来冰损失的潜力，该项目将对现有数据进行地球物理分析，以更好地限制该地区的地质。这些结果将限制旨在了解控制该地区冰盖行为的构造学的新模型。这些新模型将突出地质特性，这些地质特性对威尔克斯亚冰川盆地的冰块的未来产生最重要的控制。这种见解对于指导未来的努力旨在收集所需的现场观察，以更加充分地限制南极洲未来海平面的潜力。 第二部分：技术描述在极地环境中，向内倾斜的海洋盆地容易受到一种称为海洋冰盖不稳定性（MISI）的效果：由温暖的海水从下方侵蚀了冰架，导致的冰冰流流量。冰片响应的大小和时间尺度在很大程度上取决于沿冰层界面的物理条件，这是一阶，由盆地的构造演化控制。地形，沉积学，地热磁通和地幔粘度都在冰盖稳定性中起关键作用。但是，在大多数情况下，这些区域易受误会的固体地球参数在很大程度上是未知的。南极洲东部的威尔克斯亚冰河盆地是一个潜在易感性的区域。该项目将对威尔克斯亚冰河盆地进行综合研究，将地球物理分析与地幔流量和冰盖建模相结合，以了解冰盖在该地区的稳定性，以及相关的潜在海平面上升。这项工作将集中在四个主要目标上：（1）基于现有的地震观测以及现有的地球物理和地质数据，为该地区开发改进的构造模型； （2）使用新的构造模型和地震数据来估计上地幔的热，密度和粘度结构，并为WSB开发热流图； （3）模拟地幔流并根据我们的密度和粘度限制来评估古分片； （4）通过建模（a）使用我们的古表现量估计值对冰盖行为进行建模（a）使用我们的热流和地幔粘度估计值的未来冰盖稳定性。 最终，该项目将在WSB下生成改进的地球物理结构图像，这将使我们能够评估该地区的地球动力学起源，并评估地质参数对过去，当前和将来的冰盖行为的影响。然后，这些努力将重点介绍应成为未来地球物理部署的重点的领域和地球物理特性。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的审查标准，认为值得通过评估来获得支持。

项目成果

The Atlas of Morocco: A Plume‐Assisted Orogeny

摩洛哥地图集：羽流辅助造山运动

• DOI: 10.1029/2022gc010843
• 发表时间: 2023
• 期刊: Geosystems
• 作者: Lanari, R.;Faccenna, C.;Natali, C.;Şengül Uluocak, E.;Fellin, M. G.;Becker, T. W.;Göğüş, O. H.;Youbi, N.;Clementucci, R.;Conticelli, S.
• 通讯作者: Conticelli, S.