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: 1443248
• 负责人: Brenda Hall
• 金额: $ 16.51万
• 依托单位: University of Maine
• 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=1443248&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预测未来海平面的最大不确定性。 了解过去的冰波动提供了深入了解冰盖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。 该项目将研究过去几千年来罗斯海南部的冰川消退情况，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，提高对冰动力学的理解，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培养未来的科学家，以及将在我们的实验室开发研究项目的本科生。以前的研究表明，罗斯海冰川迅速消退，远在南部的比尔德摩尔冰川早在全新世时代（大约在现在之前11，700年开始），然后是更渐进的衰退。然而，在全新世后期的冰消作用仍然不受约束，没有时间控制的接地线之间的迁移Beardmore和斯科特冰川。 因此，我们不知道是否中全新世衰退驱动接地线迅速回到斯科特冰川目前的位置，或者如果冰盖逐渐退出，在没有显着的气候强迫或海平面变化。 后一种可能性引起了对罗斯海接地线未来稳定性的担忧。为了解决这个问题，我们将绘制并确定沿海山脉上冰川沉积物的日期，这些沉积物限制了Liv和Amundsen冰川的变薄历史。 通过将我们的年表向下延伸到这些冰川口处的浮冰水平，我们将确定它们从冰川最大期到现在的变薄历史，以及罗斯海接地线沿沿着跨南极山脉向南迁移的历史。 高分辨率测年将来自于沿沿着海拔断面收集的不规则物的Berg-10表面暴露年龄，以及前冰坝池塘海岸线内藻类的碳-14测年。地点是专门选择的，以便对这两种测年方法进行密切比较，这将限制南极Berlene-10的生产率。