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

合作研究：南罗斯湾全新世冰川消退的高分辨率重建

• 批准号: 1443346
• 负责人: John Stone
• 金额: $ 25.5万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1443346&HistoricalAwards=false
• 关键词: Collaborative; Research; resolution; Reconstruction; Holocene

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.

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。 对过去的冰波动的理解可以深入了解冰原对气候和海平面变化的反应，因此对于改善海平面预测至关重要。 该项目将在过去几千年中检查南罗斯海的脱气，以记录在相对稳定的气候和海平面的南极冰量的振荡。 我们将帮助量化冰量的变化，提高对负责的冰动态的理解，并研究对未来海平面变化的影响。该项目将通过研究生的参与以及将在我们的实验室中开发研究项目的大学生来培训未来的科学家。预览的研究表明，在全新世时期初期，在Beardmore冰川的早期（在现在开始大约11,700年开始），Ross Sea Sea Dewlaciation远至Beardmore Glacier，随后发生了更多的渐进衰退。然而，全新世的后半部分的脱水量仍然受到巨大限制，没有时间顺序控制比尔多莫尔和斯科特冰川之间的接地线迁移。 因此，我们不知道中新世的衰退是将接地线迅速恢复到目前在Scott冰川的位置，或者在没有明显的气候强迫或Eustatic海平面变化的情况下，冰盖是否逐渐退出。 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，我们将在沿海山脉上绘制和日期冰川沉积物，以限制Liv和Amundsen冰川的变薄病史。 通过将我们的年表扩展到这些冰川嘴的浮冰水平，我们将使它们的变薄历史从冰川最大到现在，以及沿跨天然山脉向南的罗斯海地面线的迁移。 高分辨率的日期将来自沿着海拔横断面收集的不稳定的铍-0表面暴露年龄，以及从以前的冰烧池体内的海岸线内的藻类藻类日期。已经选择了站点是为了允许对这两种约会方法进行仔细比较，这将对南极10的生产率受到限制。