Unpinning of the Ross Ice Shelf from Ross Bank

南极冰架是由南极洲内部的冰川流出大陆边缘并延伸到海洋中而形成的。这些冰架可以作为一个支撑，限制冰从大陆内部流向海洋。由此造成的支撑冰的损失可能会导致冰流加速将冰运送到海洋，造成负冰质量平衡和全球海平面上升。因此，南极冰架的快速变薄是一个主要关切。这些厚冰架的范围通常由冰下地形高点或固定点控制，如近海岛屿和/或海底银行，这些岛屿和/或海底银行往往会减缓内部冰川冰的离岸排放。冰架从钉扎点的分离可能导致冰架快速后退，减少支撑作用。问题仍然存在，现代冰架如何与这些固定点分离，以及冰架松开后，冰量的离岸流动如何重新组织？该项目从罗斯海获取沉积物岩心和海底调查，将用于详细重建罗斯冰架（RIS）如何以及何时从海底银行中脱离，以了解南极西部冰盖（WAIS）目前的稳定性。如果罗斯冰架脱离包括罗斯福岛在内的现有固定点，如何，为什么以及何时罗斯冰架（RIS）从罗斯银行unpinned评估冰盖和冰架的行为在最近的unpinning事件。RIS上保存的流动条纹和裂谷轨迹表明，西南极冰盖流动模式的变化表明了冰架的近期演变（即上千年）。从最近的罗斯福岛气候演变项目中收集的冰芯可能会提供这段时间内大气和冰面海拔变化的高分辨率记录。这些现有的数据沿着收集的数据从两个巡航罗斯海将被用来重建过去的冰架动态罗斯银行周围，以确定RIS未来的敏感性和响应的unpinning。罗斯银行的这项研究将提供急需的地面真相模型预测的原因和影响与冰架unpinning的关系。在罗斯海的两次巡航中的活动包括地震测量、多波束、卡斯滕和巨型活塞岩心。除了对冰盖动态和海平面上升的科学影响外，这项研究还提供了机会，对四名研究生和四名本科生进行地球物理和地质数据采集、处理、采样、解释和演示方面的培训。路易斯安那州立大学团队将与当地学校和公众分享成果;该项目为路易斯安那州的高中科学教师提供实地经验。该奖项反映了NSF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。

The Antarctic ice shelves are created when glaciers from the interior of Antarctica flow beyond the edges of the continent and extend into the oceans. These ice shelves can act as a buttress that limits the flow of ice from the interior of the continent to the oceans. The resulting loss of buttressing ice likely causes an acceleration of ice-streams transporting ice to the oceans causing negative ice mass balance and global sea-level rise. Thus, the high rates of Antarctic ice shelf thinning are a major concern. The extent of these thick ice shelves is often controlled by subglacial topographic highs or pinning points such as offshore islands and/or submarine banks which tend to slow the offshore discharge of interior glacier ice. The detachment of ice shelves from pinning points may lead to rapid ice shelf retreat reducing buttressing. The questions remain, how might modern-day ice shelves decouple from these pinning points and how would offshore flow of ice volume re-organize after an ice shelf unpins? This project acquires sediment cores and sea floor surveys from the Ross Sea that will be used to generate a detailed reconstruction of how and when the Ross Ice Shelf (RIS) unpinned from a submarine bank in order to gain perspective on the current stability of the West Antarctic Ice Sheet (WAIS) and the potential for a future disruption of the Ross Ice Shelf should it detach from existing pinning points including Roosevelt Island.The research investigates the how, why and when the Ross Ice Shelf (RIS) unpinned from Ross Bank to assess ice sheet and ice shelf behavior during a recent unpinning event. Changes in West Antarctic Ice Sheet flow patterns as suggested by flow stripes and rift tracks preserved on the RIS suggest recent evolution (i.e. last millennial) of the ice shelf. Ice cores collected from the recent Roosevelt Island Climate Evolution project are likely to provide a high-resolution record of atmospheric and ice-surface elevation changes during this time interval. These existing data along with the collection of data from two cruises to the Ross Sea will be used to reconstruct past ice shelf dynamics around Ross Bank to determine RIS future susceptibility and response of unpinning. This study of the Ross Bank will provide much needed ground truth for model prediction of cause and effect relationships associated with ice-shelf unpinning. Activities during two cruises to the Ross Sea include seismic surveying, multibeam, and Kasten and Jumbo Piston cores. In addition to the scientific broader impacts on ice sheet dynamics and sea level rise, this study provides the opportunity to train four graduate and four undergraduate students on geophysical- and geological-data acquisition, processing, sampling, interpretation and presentation. The LSU team will share the results with the public with local schools and the public; the project provides field experience for a Louisiana high-school science teacher.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.