Airborne geophysical investigation targets basal boundary conditions for the Institute and Moller ice streams, West Antarctica

机载地球物理调查的目标是南极洲西部研究所和莫勒冰流的基础边界条件

• 批准号: NE/G013071/1
• 负责人: Martin Siegert
• 金额: $ 84.41万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG013071%2F1
• 关键词: Airborne; geophysical; investigation; targets; basal

The Institute and Möller ice streams (IIS/MIS) drain about 20% of the West Antarctic Ice Sheet (WAIS) to the Ronne Ice Shelf, yet our knowledge of their current form and flow history is severely restricted compared with other fast flowing regions in West Antarctica. Data relating to the ice thickness and the ice-sheet bed is limited to reconnaissance transects acquired in the 1970s. Bingham and Siegert (2007) inspected these data, and showed the remarkably smooth and flat bed was similar to the Siple Coast ice streams that drain to the Ross Ice Shelf. As the Siple Coast region is thought to be underlain by marine sediments, deposited when the ice sheet size was smaller than today, Bingham and Siegert (2007) concluded a similar, probably simultaneous, history for the Institute/Möller region. The implications of this finding are significant for future changes in West Antarctica. Bingham and Siegert's (2007) analysis allows us to hypothesise substantial former ice-shelf loss and grounding line retreat in two of the three major drainage outlets of West Antarctica. An extensive airborne geophysical survey of the Institute and Möller ice streams is therefore clearly warranted, to test this hypothesis and better understand the risk of future change. The survey will also allow a better depiction of bed topography and geological boundary conditions in West Antarctica, which will allow us to better quantify the flow and form of the entire WAIS through numerical modelling. The project's objectives are as follows. 1. To undertake an airborne geophysical survey of the Institute and Möller ice streams of West Antarctica. 2. To quantify bed topography and measure bed roughness from radar data. 3. To map englacial structures (layering and crevasses). 4. To determine power reflection coefficients, forming an appreciation of basal water distribution. 5. To analyse magnetic and gravity anomalies to derive geological boundary conditions for ice flow. 6. To employ numerical modelling to quantify modern and ancient ice flow processes. 7. To use numerical modelling to predict the risk of former changes reoccurring. This project will result in the following deliverables: 1. The quantification of subglacial topography (and bed roughness) in a hitherto poorly known region of West Antarctica. This information will be made available to the BEDMAP II database, and will make a fundamental contribution as an ice sheet modelling boundary condition. We will analyse these data to determine landscape evolution and ice sheet history. 2. The classification of subglacial thermal conditions and locations of subglacial lakes. This will allow us to comprehend how ice stream flow and subglacial lake/hydrology evolution is both interrelated and affected by subglacial geology and thermal conditions. 3. The measurement of the englacial structure in the WAIS. We will analyse this information to calculate the flow history of the ice sheet and to delineate the margins of the IIS and MIS both now and in the recent past. 4. The definition of crustal structure and subglacial geology of the IIS and MIS catchments of the WAIS. The glacial history of the WAIS is of direct relevance to assessments of the present day risk of collapse and sea level rise. We aim to report our results directly to the international scientific community by linking to the Scientific Committee on Antarctic Research's (SCAR) scientific research programme entitled Antarctic Climate Evolution (ACE), which integrates geology and geophy sical datasets, forming hypotheses concerning past changes, which can be tested through modelling. The ACE link also allows us to disseminate results to the IPCC through SCAR's observer status in that organisation. We will also make results available to the SCAR programme named Subglacial Antarctic Lake Environments (SALE) and will contribute the new magnetic dataset to the international Antarctic Digital Magnetic Anomaly Project.

研究所和Möller冰流（IIS/MIS）将南极西部冰原（WAIS）的约20%流到Ronne冰架，但与南极洲西部其他快速流动的地区相比，我们对其当前形式和流动历史的了解严重受限。有关冰厚和冰盖床的数据仅限于1970年代获得的侦察样带。Bingham和Siegert（2007）检查了这些数据，发现非常光滑和平坦的床与流入罗斯冰架的简单海岸冰流相似。由于简单海岸地区被认为是在冰盖比现在小的时候沉积的海洋沉积物，Bingham和Siegert（2007）为研究所/Möller地区总结了一个类似的，可能同时发生的历史。这一发现对西南极洲未来的变化意义重大。Bingham和Siegert（2007）的分析允许我们假设在西南极洲的三个主要排水口中的两个存在大量的前冰架损失和接地线退缩。因此，显然有必要对研究所和Möller冰流进行广泛的航空地球物理调查，以检验这一假设并更好地了解未来变化的风险。该调查还将使我们能够更好地描述南极洲西部的床地形和地质边界条件，这将使我们能够通过数值模拟更好地量化整个WAIS的流动和形式。该项目的目标如下。1. 对研究所和Möller南极洲西部冰流进行航空地球物理调查。利用雷达数据量化床层地形和测量床层粗糙度。3. 绘制冰川结构（分层和裂缝）。4. 确定功率反射系数，形成对基水分布的认识。5. 分析磁重异常，推导冰流的地质边界条件。6. 采用数值模拟来量化现代和古代冰流过程。7. 使用数值模拟来预测以前的变化再次发生的风险。本项目将产生以下可交付成果：迄今为止鲜为人知的西南极洲地区冰下地形（和河床粗糙度）的量化。这些资料将提供给BEDMAP II数据库，并将作为冰原边界条件模型作出根本贡献。我们将分析这些数据，以确定景观演变和冰盖历史。2. 冰下热条件的分类和冰下湖泊的位置。这将使我们了解冰流和冰下湖泊/水文演变是如何相互关联的，并受到冰下地质和热条件的影响。3. WAIS中冰川结构的测量。我们将分析这些信息，以计算冰盖的流动历史，并划定现在和最近过去的IIS和MIS的边缘。4. 西洋带IIS和MIS流域的地壳结构和冰下地质定义。西海冰川的冰川历史直接关系到对现今崩塌和海平面上升风险的评估。我们的目标是通过与南极研究科学委员会（SCAR）的南极气候演变（ACE）科学研究计划联系，直接向国际科学界报告我们的结果，该计划整合了地质和地球物理数据集，形成了关于过去变化的假设，这些假设可以通过建模进行测试。ACE的联系也使我们能够通过SCAR在IPCC的观察员地位向该组织传播结果。我们还将把结果提供给SCAR项目冰下南极湖环境（SALE），并将向国际南极数字磁异常项目提供新的磁数据集。

项目成果

Evidence from ice shelves for channelized meltwater flow beneath the Antarctic Ice Sheet

• DOI: 10.1038/ngeo1977
• 发表时间: 2013-11-01
• 期刊: NATURE GEOSCIENCE
• 影响因子: 18.3
• 作者: Le Brocq, Anne M.;Ross, Neil;Siegert, Martin J.
• 通讯作者: Siegert, Martin J.

Inland extent of the Weddell Sea Rift imaged by new aerogeophysical data

通过新的航空地球物理数据成像的威德尔裂谷的内陆范围

• DOI: 10.1016/j.tecto.2012.09.010
• 发表时间: 2013
• 期刊: Tectonophysics
• 影响因子: 2.9
• 作者: Jordan T

Controls on subaerial erosion rates in Antarctica

• DOI: 10.1016/j.epsl.2018.08.018
• 发表时间: 2018-11
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: S. Marrero;A. Hein;M. Naylor;Mikael Attal;Richard A. Shanks;Kate Winter;J. Woodward;S. Dunning

Heat and groundwater transport between the Antarctic Ice Sheet and subglacial sedimentary basins from electromagnetic geophysical measurements

通过电磁地球物理测量了解南极冰盖与冰下沉积盆地之间的热量和地下水传输

• DOI: 10.1190/segam2019-3215566.1
• 发表时间: 2019
• 作者: Kulessa B

Antarctic basal environment shaped by high-pressure flow through a subglacial river system

冰下河流系统高压流塑造的南极基底环境

• DOI: 10.1038/s41561-022-01059-1
• 发表时间: 2022
• 期刊: Nature Geoscience
• 影响因子: 18.3
• 作者: Dow C