Collaborative Research: Pleistocene East Antarctic Ice Sheet History as Recorded in Sediment Provenance and Chronology of High-elevation TAM Moraines

合作研究：沉积物来源和高海拔 TAM 冰碛年代记录的更新世南极东部冰盖历史

基本信息

批准号：
0944578
负责人：
Kathy Licht
金额：
$ 17.79万
依托单位：
Indiana University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2010
资助国家：
美国
起止时间：
2010-06-01 至 2013-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944578&HistoricalAwards=false
关键词：
Collaborative Research Pleistocene East Antarctic

项目摘要

Intellectual MeritThe proposed work will investigate changes in the compositional variation of glacial tills over time across two concentric sequences of Pleistocene moraines located adjacent to the heads of East Antarctic outlet glaciers in the Transantarctic Mountains (TAM). The chronologic framework for this work will be generated from cosmogenic exposure ages of boulders on prominent morainal ridges. The PIs hypothesize that variations in till composition may indicate a change in ice flow direction or a change in the composition of the original source area, while ages of the moraines provide a long-term terrestrial perspective on ice sheet dynamics. Both results are vital for modeling experiments that aim to reconstruct the East Antarctic Ice Sheet and assess its role in the global climate system and its potential impact on global sea level rise. The variation of till compositions through time also allows for a more accurate interpretation of sediment cores from the Ross Sea and the Southern Ocean. Additionally, till exposures at the head of some East Antarctic outlet glaciers have been shown to contain subglacial material derived from East Antarctic bedrock, providing a window through the ice to view East Antarctica?s inaccessible bedrock. Till samples will be collected from two well-preserved sequences of moraine crests at Mt. Howe (head of Scott Glacier) and Mt. Achernar (between Beardmore and Nimrod Glaciers). Each size fraction in glacial till provides potentially valuable information, and the PIs will measure the petrography of the clast and sand fractions, quantitative X-ray diffraction on the crushed 2mm fraction, elemental abundance of the silt/clay fraction, and U/Pb of detrital zircons in the sand fraction. Data collection will rely on established methods previously used in this region and the PIs will also explore new methods to assess their efficacy. On the same moraines crests sampled for provenance studies, the PIs will sample for cosmogenic surface exposure analyses to provide a chronologic framework at the sites for provenance changes through time. Broader ImpactThe proposed research involves graduate and undergraduate training in a diverse array of laboratory methods. Students and PIs will be make presentations to community and campus groups, as well as conduct interviews with local news outlets. The proposed work also establishes a new, potentially long-term, collaboration between scientists at IUPUI and LDEO and brings a new PI (Kaplan) into the field of Antarctic Earth Sciences.

智力优点拟议的工作将调查冰川耕种的组成变化，随着时间的流逝，位于跨跨山脉（TAM）的两个更新世的莫拉因的同心序列。这项工作的时间顺序框架将是由巨大山脊上的巨石的宇宙暴露年龄产生的。 PI假设直到组成的变化可能表明冰流方向的变化或原始源区域组成的变化，而Moraines的年龄则在冰盖动力学上提供了长期的陆地视角。这两个结果对于旨在重建东南极冰盖并评估其在全球气候系统中的作用及其对全球海平面上升的潜在影响的实验至关重要。直到时间的成分的变化还可以更准确地解释罗斯海和南大洋的沉积物核心。此外，直到某些南极东部出口冰川的头部曝光已被证明包含源自南极东基岩衍生的冰川材料，从而通过冰提供一个窗户，可查看南极洲东部的不可接受的基岩。直到样品将从保存完好的冰ora峰序列（Scott Glacier的头）和Achernar山（Beardmore和Nimrod冰川之间）收集。冰川直至中的每个大小分数都提供了潜在的有价值的信息，PI将测量碎屑和砂分的岩石摄影，碎屑2mm级分的定量X射线衍射，砂浆/粘土馏分的元素丰度，以及砂浆中碎屑的U/Pb。数据收集将依赖于以前在该区域中使用的既定方法，PIS还将探索评估其功效的新方法。在相同的Moraines波峰上，采样用于出处研究，PI将采样宇宙源表面暴露分析，以在地点提供时间顺序的框架，以随着时间的推移出处。更广泛的影响拟议的研究涉及各种实验室方法的毕业和本科培训。学生和PI将向社区和校园团体进行演讲，并与当地新闻媒体进行采访。拟议的工作还建立了IUPUI和LDEO科学家之间的新型长期合作，并将新的PI（Kaplan）带入了南极地球科学领域。