Deglacial Chronology of the Northern Scott Coast from Relative Sea-Level Curves

9909104 霍尔该奖项为一个项目提供了三年的支持，该项目旨在开发自末次盛冰期（LGM）以来西北罗斯海海湾（北方斯科特海岸）地面冰衰退的放射性碳年代学。 南极冰川学中一个关键的悬而未决的问题是以海洋为基础的西南极冰盖（WAIS）的稳定性。了解当前和未来稳定性的一种方法是检查其过去的行为。 特别是，从大陆架上的LGM位置的冰川消退的时间是至关重要的隔离机制（海平面，气候，海洋温度和内部动力学），控制WAIS动态。 北方斯科特海岸可能是第一个没有冰的地区，因此对隔离触发机制至关重要。 罗斯海海湾的最初撤退被认为早在17，000年前就开始了;与巴巴多斯珊瑚记录中的海平面上升相对应。 相比之下，最近的冰川地质测绘和相对的海平面工作，从南部斯科特海岸表明，冰消的罗斯海海湾是一个全新世事件，向南接地线迁移过去罗斯岛前不久6500 14 C年。B.P. 这一年表表明，海平面上升不可能驱动接地线撤退到西普尔海岸，因为冰消期海平面上升基本上是由中全新世完成的。 斯科特海岸南部工作的一个不足之处是，它不能区分可能的触发机制，启动撤退，因为它是450公里的LGM接地线位置。 在本项目中，相对海平面（RSL）曲线将建立在一个断面沿着北方斯科特海岸加速器质谱仪14 C日期的海豹皮肤和贝壳内提出的海滩。 这些曲线将提供有关从罗斯海海湾西北部上传接地冰的时间的信息。 这项研究应有助于评估那些可能引发冰川消退，从而控制南极西部冰盖（WAIS）的范围的因素。

9909104 HallThis award provides support for three years for a project to develop a radiocarbon chronology for recession of grounded ice from the northwestern Ross Sea Embayment (northern Scott Coast) since the Last Glacial Maximum (LGM). A key unresolved question in Antarctic glaciology concerns the stability of the marine-based West Antarctic ice sheet (WAIS). One way to gain insight into present and future stability is to examine its past behavior. In particular, the timing of deglaciation from the LGM position on the continental shelf is critical for isolating the mechanisms (sea level, climate, ocean temperature, and internal dynamics) that control WAIS dynamics. The northern Scott Coast was likely the first area to become free of grounded ice and hence is critical for isolating triggering mechanisms. Initial retreat from the Ross Sea Embayment was thought to have begun as early as 17,000 years ago; corresponding to the rise in sea level see in the Barbados coral record. In contrast, recent glacial geologic mapping and relative sea-level work from the southern Scott Coast suggests that deglaciation of the Ross Sea Embayment was a Holocene event, with southward grounding-line migration past Ross Island shortly before 6500 14C yr. B.P. This chronology suggests that rising sea level could not have driven grounding-line retreat to the Siple Coast, because deglacial sea-level rise essentially was accomplished by mid-Holocene. One deficiency in the southern Scott Coast work is that it cannot differentiate among the possible triggering mechanisms that initiated retreat because it is 450 km from the LGM grounding-line position. In this project, relative sea level (RSL) curves will be constructed on a transect along the northern Scott Coast from accelerator mass spectrometer 14C dates of seal skin and shells within raised beaches. These curves will provide information concerning the timing of the uploading of grounded ice from the northwestern Ross Sea Embayment. This study should help to evaluate those factors which could have triggered deglaciation and hence controlled the extent of the West Antarctic ice sheet (WAIS).