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Collaborative Research: Tephrochronology of a South Pole Ice Core

合作研究：南极冰芯的年代学

基本信息

批准号：
1543361
负责人：
Andrei Kurbatov
金额：
$ 20.5万
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：
2016-04-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1543361&HistoricalAwards=false
关键词：
Collaborative Research Tephrochronology South Pole

项目摘要

Dunbar/1543454Antarctic ice cores offer unparalleled records of earth?s climate back to almost one million years and perhaps beyond. Layers of volcanic ash (tephra) embedded in glacial ice can be used to establish an accurate ice core chronology. In order to use a visible or ultrafine volcanic ash layer as a time-stratigraphic marker, a unique geochemical fingerprint must be established, and this forms the basis of our research. This award will investigate the volcanic record in the 1751 m ice core that was completed at the South Pole during the 2015/16 field season. The core is in an ideal location to link the existing, established, volcanic records in East and West Antarctica, and therefore to connect and integrate those records, allowing the climate records of ice cores to be directly compared, as well as to focus research on the most widespread and significant volcanic eruptions from West Antarctica. Tephra derived from well-dated, large, tropical volcanic eruptions that may have had an impact on climate will also be studied. Recent success in identifying and analyzing very fine ash particles from these types of eruptions makes it likely that we will be able to pinpoint some of these eruptions, which will allow the sulfate peaks associated with these layers to be positively identified and dated. Volcanic forcing time series developed from earlier South Pole ice cores based on preserved sulfate were crucial for testing climate models, but without tephra analysis, the origin of these layers remains uncertain. Work on the tephra layers in the South Pole ice core has a number of significant specific objectives, some with practical applications to the basic science goals of Antarctic ice coring, and others that represent independent scientific contributions in their own right. These include: (1) providing independently dated time-intervals in the core, particularly for the deepest ice, (2) quantitatively linking tephra records across Antarctica with the goal of allowing direct and robust climate comparisons between these different parts of the continent, (3) providing information for large local eruptions, that will lead to direct estimates of eruption magnitude and dispersal patterns of Antarctic volcanoes, several of which will likely erupt again. The initial stages of the work will be carried out by identifying silicate-bearing horizons in the ice core, using several methods. Once found, silicate particles will be imaged so that morphological characteristics of the particles can be used to identify volcanic origin. Particles identified as tephra will then be chemically analyzed using electron microprobe and laser ablation ICP-MS. Samples that yield a robust chemical fingerprint will be statistically correlated to known eruptions, and this will be used to address the goals described above. Broader impacts of this project fall into the areas of education of future generation of researchers, outreach and international cooperation. These activities will continue to promote forward progress in integrating the Antarctic tephra record and more broadly tying it to the global volcanic record.

邓巴/1543454南极冰芯提供无与伦比的地球记录？气候回到近100万年，也许更远。嵌入冰川冰中的火山灰（火山灰）层可以用来建立准确的冰芯年表。为了使用可见或超细火山灰层作为时间地层标志，必须建立独特的地球化学指纹，这构成了我们研究的基础。该奖项将调查2015/16年野外季节在南极完成的1751米冰芯中的火山记录。该冰芯所处的位置非常理想，可以将东南极洲和西南极洲现有的火山记录联系起来，从而将这些记录联系起来并加以整合，从而可以直接比较冰芯的气候记录，并将研究重点放在西南极洲最广泛和最重要的火山爆发上。还将研究可能对气候产生影响的年代久远的大型热带火山爆发产生的火山碎屑。最近成功地识别和分析了这些类型的火山喷发的非常细的火山灰颗粒，这使得我们有可能能够精确地确定其中的一些火山喷发，这将使与这些层相关的硫酸盐峰得到积极的识别和定年。根据保存的硫酸盐从早期南极冰芯中开发的火山强迫时间序列对于测试气候模型至关重要，但如果没有火山灰分析，这些层的起源仍然不确定。关于南极冰芯火山灰层的工作有若干重要的具体目标，其中一些目标可实际应用于南极冰芯取芯的基本科学目标，另一些目标本身就是独立的科学贡献。其中包括：（1）提供独立的地核时间间隔，特别是最深的冰，（2）定量地联系南极洲各地的火山灰记录，目的是在南极洲这些不同地区之间进行直接和可靠的气候比较，（3）提供大规模局部喷发的信息，这将导致对南极火山喷发规模和扩散模式的直接估计，其中几个可能会再次爆发这项工作的最初阶段将通过使用几种方法确定冰芯中含硅酸盐的地层来进行。一旦发现，硅酸盐颗粒将被成像，以便颗粒的形态特征可用于识别火山起源。然后，将使用电子微探针和激光消融ICP-MS对被确定为火山灰的颗粒进行化学分析。产生强大化学指纹的样品将与已知喷发进行统计相关，这将用于实现上述目标。这一项目的更广泛影响涉及未来一代研究人员的教育、外联和国际合作等领域。这些活动将继续推动在整合南极火山喷发记录和更广泛地将其与全球火山记录联系起来方面取得进展。