A detailed framework of Marine Isotope Stages 4 and 5 volcanic events recorded in two Greenland ice-cores
A detailed framework of Marine Isotope Stages 4 and 5 volcanic events recorded in two Greenland ice-cores
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DOI：
10.1016/j.quascirev.2011.05.001
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发表时间：
2012-03-12
影响因子：
4
通讯作者：
Wastegard, Stefan
中科院分区：
文献类型：
--
作者：
Abbott, Peter M.;Davies, Siwan M.;Wastegard, Stefan
格陵兰冰芯中的硫酸盐记录表明，在末次冰期，海洋同位素4和5期的火山喷发比其他时期的火山喷发发生率高，但很少有人关注与这些火山喷发有关的火山碎屑沉积以及火山喷发的性质和起源。在这里，我们提出了一个详细的火山灰年代学框架的产品15火山事件跨越这段时间：其中大部分已被保存为隐火山灰层的地平线内的格陵兰记录。在这些视野内的个别玻璃碎片的主要元素组成表明，13个火山喷发起源于冰岛和这些事件中的6个可以与特定的火山系统的卡特拉，格里姆斯沃滕，格里姆斯沃滕Kverkfjoll和Reykjanes或Veidivotn-Bardarbunga。对于其余的冰岛层位，可以根据岩石组的亲缘关系，建议其来源于裂谷带或侧翼带。两个层位与扬马延火山系统的一个源相关联，这是在格陵兰冰芯中首次发现来自该系统的物质。强大的地球化学特征，独立的年龄为这些视野（来自GICCO 5冰芯年代学）和地层位置相对于格陵兰冰芯记录的Dansgaard-Oeschger气候事件代表了一个关键的框架，提供了新的信息的频率和性质的火山事件发生在北大西洋地区在MIS 4和5。这个框架，现在可以利用在评估的差异的时间和速率的响应千年尺度的气候事件，这一时期的特点，通过使用火山灰层位的时间同步的联络线，其他古气候序列。(C)2011爱思唯尔有限公司保留所有权利。
Sulphate records from Greenland ice-cores indicate that Marine Isotope Stages 4 and 5 were charactensed by a higher incidence of large volcanic eruptions than other periods during the last glacial period, however, few investigations have focused on tephra deposits associated with these volcanic eruptions and the nature and origin of the events. Here we present a detailed tephrochronological framework of the products of 15 volcanic events spanning this interval: the majority of which have been preserved as cryptotephra horizons within the Greenland records. The major element compositions of individual glass shards within these horizons indicate that 13 of the eruptions originated from Iceland and 6 of these events can be correlated to the specific volcanic systems of Katla, Grimsvotn, Grimsvotn-Kverkfjoll and either Reykjanes or Veidivotn-Bardarbunga. For the remaining Icelandic horizons a source from either the rift zone or a flank zone can be suggested based on rock suite affinities. Two horizons have been correlated to a source from the Jan Mayen volcanic system which represents the first discovery of material from this system within any Greenland ice-cores. The robust geochemical characterisations, independent ages for these horizons (derived from the GICCO5 ice-core chronology) and stratigraphic positions relative to the Dansgaard-Oeschger climate events recorded in the Greenland ice-cores represent a critical framework that provides new information on the frequency and nature of volcanic events occurring in the North Atlantic region during MIS 4 and 5. This framework can now be utilised in the assessment of the differential timing and rate of response to the millennial-scale climatic events that characterised this period, through the use of the tephra horizons as time-synchronous tie-lines to other palaeoclimatic sequences. (C) 2011 Elsevier Ltd. All rights reserved.