Volcanism and the Greenland ice-cores: the tephra record
Volcanism and the Greenland ice-cores: the tephra record
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DOI：
10.1016/j.earscirev.2012.09.001
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发表时间：
2012-11-01
影响因子：
12.1
通讯作者：
Davies, Siwan M.
中科院分区：
文献类型：
--
作者：
Abbott, Peter M.;Davies, Siwan M.
近年来，人们越来越认识到温度年代学在古气候研究中所提供的巨大潜力，这使人们对保存在格陵兰冰芯内的温度记录重新产生了兴趣。这种更新是随着连续流分析技术的发展而发生的，该技术提供了高分辨率的火山气溶胶记录。这些化学记录对于确定由玻璃碎片组成的温弗拉地层具有相当大的价值，也为新的高精度冰芯时间标度提供了基础，从而可以确定火山事件的年龄。冰芯中玻璃碎片的Tephra层位在以下方面发挥着关键作用：(1)测试和建立冰芯和其他序列的时间框架；(2)同步不同的古气候序列并测试阶段关系；(3)大气路径重建；(4)验证火山气溶胶峰的来源。在此，我们回顾了GRIP、GISP2和NGRIP岩心25年来的辐射层研究成果。我们根据最近开发的时间尺度提供了高精度的层位年龄，并将格陵兰冰盖上沉积的45次火山事件产物的地球化学特征结合在一起，并在岩心中进行了识别。火山气溶胶峰的数量与迄今已确定的玻璃碎片的温度层的数量之间存在明显的差异。然而，这种综合强调了格陵兰冰芯的关键作用，首先在冰岛火山爆发历史的重建中，其次在促进这些关键气候档案与北大西洋海洋序列的相关性方面，一些冰层具有相当大的价值。其他值得注意的问题包括这些岩心的潜力，可以从更远的火山来源（如北美）保存火层，解决围绕Thera火山爆发的争论，以及观察到一些火层被保存在冰中，没有同期的火山气溶胶信号。(C) 2012 Elsevier B.V.版权所有
In recent years, increased awareness of the considerable potential offered by tephrochronology in palaeoclimatic studies has fuelled a renewed interest in the tephra record preserved within the Greenland ice-cores. This renewal has occurred in tandem with the development of continuous flow analysis techniques, which provide high-resolution volcanic aerosol records. These chemical records are of considerable value for identifying tephra horizons composed of glass shards and also provide the basis for a new high-precision ice-core timescale, thus allowing ages to be assigned to volcanic events. Tephra horizons of glass shards in the ice-cores play a critical role for (1) testing and building chronological frameworks for the ice-cores and other sequences, (2) synchronising disparate palaeoclimatic sequences and testing phase relationships, (3) atmospheric pathway reconstruction, and (4) verifying the source of volcanic aerosol peaks. Here we review the results of over 25 years of research into tephra horizons in the GRIP, GISP2 and NGRIP cores. We provide high-precision ages for horizons based on recently developed timescales and draw together geochemical characterisations of the products of 45 volcanic events deposited on the Greenland ice sheet and identified in the cores. There is a clear disparity between the number of volcanic aerosol peaks and the number of tephra horizons of glass shards identified thus far. However, this synthesis highlights the critical role of the Greenland ice-cores, firstly in the reconstruction of the history of Icelandic volcanic eruptions, and secondly the considerable value of some tephra horizons in facilitating the correlation of these key climatic archives to North Atlantic marine sequences. Other noteworthy issues include the potential of these cores to preserve tephra horizons from more distal volcanic sources such as North America, to resolve the debate surrounding the Thera eruption, and the observation that some tephra horizons are preserved within the ice without coeval volcanic aerosol signals. (C) 2012 Elsevier B.V. All rights reserved.