Collaborative Research: High-resolution Reconstruction of Holocene Deglaciation in the Southern Ross Embayment

南极冰盖对未来气候变化的反应被认为是未来海平面预测中最大的不确定性。 了解过去的冰层波动可以深入了解冰盖对气候和海平面变化的响应，因此对于改进海平面预测至关重要。 该项目将研究过去几千年来罗斯海南部的冰川消融情况，以记录气候和海平面相对稳定时期南极冰量的波动。 我们将帮助量化冰量的变化，增进对冰动态的了解，并研究对未来海平面变化的影响。该项目将通过研究生和本科生的参与来培训未来的科学家，他们将在我们的实验室开发研究项目。 先前的研究表明，在全新世早期（大约开始于距今 11,700 年前），罗斯海冰川快速消退，一直延伸至比尔德莫尔冰川以南，随后是更缓慢的衰退。然而，全新世后半段的冰川消融仍然受到很少的限制，对比尔德莫尔冰川和斯科特冰川之间的接地线迁移没有时间控制。 因此，我们不知道全新世中期经济衰退是否使接地线迅速回到斯科特冰川目前的位置，或者冰盖是否在没有显着气候强迫或海平面升降的情况下逐渐后退。 后一种可能性引起了人们对罗斯海接地线未来稳定性的担忧。为了解决这个问题，我们将绘制沿海山脉上限制利夫冰川和阿蒙森冰川变薄历史的冰川沉积物的地图和年代。 通过将我们的年代学延伸到这些冰川口的浮冰水平，我们将确定冰川从盛期到现在的变薄历史，以及罗斯海接地线沿着横贯南极山脉向南迁移的历史。 高分辨率测年将来自沿高程横断面收集的不稳定物的铍 10 表面暴露年龄，以及前冰坝池塘海岸线内藻类的碳 14 年龄。专门选择地点是为了密切比较这两种测年方法，这将限制南极铍 10 的生产率。

The response of the Antarctic Ice Sheet to future climatic changes is recognized as the greatest uncertainty in projections of future sea level. An understanding of past ice fluctuations affords insight into ice-sheet response to climate and sea-level change and thus is critical for improving sea-level predictions. This project will examine deglaciation of the southern Ross Sea over the past few thousand years to document oscillations in Antarctic ice volume during a period of relatively stable climate and sea level. We will help quantify changes in ice volume, improve understanding of the ice dynamics responsible, and examine the implications for future sea-level change. The project will train future scientists through participation of graduate students, as well as undergraduates who will develop research projects in our laboratories.Previous research indicates rapid Ross Sea deglaciation as far south as Beardmore Glacier early in the Holocene epoch (which began approximately 11,700 years before present), followed by more gradual recession. However, deglaciation in the later half of the Holocene remains poorly constrained, with no chronological control on grounding-line migration between Beardmore and Scott Glaciers. Thus, we do not know if mid-Holocene recession drove the grounding line rapidly back to its present position at Scott Glacier, or if the ice sheet withdrew gradually in the absence of significant climate forcing or eustatic sea level change. The latter possibility raises concerns for future stability of the Ross Sea grounding line. To address this question, we will map and date glacial deposits on coastal mountains that constrain the thinning history of Liv and Amundsen Glaciers. By extending our chronology down to the level of floating ice at the mouths of these glaciers, we will date their thinning history from glacial maximum to present, as well as migration of the Ross Sea grounding line southwards along the Transantarctic Mountains. High-resolution dating will come from Beryllium-10 surface-exposure ages of erratics collected along elevation transects, as well as Carbon-14 dates of algae within shorelines from former ice-dammed ponds. Sites have been chosen specifically to allow close comparison of these two dating methods, which will afford constraints on Antarctic Beryllium-10 production rates.