An overview of distal tephrochronology in northern Europe during the last 1000 years
An overview of distal tephrochronology in northern Europe during the last 1000 years
复制标题
DOI：
10.1002/jqs.1269
复制
发表时间：
2009-07
影响因子：
2.3
通讯作者：
S. Wastegård;S. Davies
中科院分区：
文献类型：
--
作者：
S. Wastegård;S. Davies
在北方欧洲的远源泥炭和湖泊沉积序列中发现了几个上个千年的火山碎屑层，形成了一个对古环境调查具有重要价值的火山事件框架。这个框架内的大部分火山岩都起源于冰岛，但也发现了来自扬马延的远源层。主要的运输途径，在东-东南方向，导致这些火山岩沉积在北方欧洲的一些陆地沉积。火山喷发的火山灰（>63% SiO2）在这些地点占主导地位，尽管许多远端地区的文献记录报告火山灰来自几次玄武岩喷发。在这里，我们概述了这些火山岩的分布、碎片浓度和地球化学，以强调解决关键测年问题的最重要的等时线。特别是在北方欧洲的许多不同地点发现了三个层位-- Hekla‐1（公元1104年）、Öræfajökull（公元1362年）和Askja（公元1875年），因此它们是改进和验证年代模型以及同步过去1000年记录的宝贵联系点。此外，我们提出了新的数据识别火山熔岩从格里姆火山系统内的Lomonosovfonna冰帽斯瓦尔巴群岛，表明一些火山熔岩已被运输2000公里，北至79° N沿着东北的轨迹。这一发现突出了利用火山灰年代学作为位于更北部地区的古档案的相关工具的潜力，以及不同喷发的沉降物的复杂性质。版权所有© 2009约翰威利父子有限公司。
Several tephra layers from the last millennium have been identified in distal peat and lake sediment sequences in northern Europe, forming a framework of volcanic events of great value for palaeoenvironmental investigations. Most of the tephras within this framework have an origin in Iceland, but distal layers from Jan Mayen have also been identified. The predominant transport pathway, in an easterly–southeasterly direction, has led to the deposition of these tephras in a number of terrestrial deposits in northern Europe. Ash from silicic eruptions (>63% SiO2) dominate at these sites, even though many of the documentary records in distal areas report tephra fall from several basaltic eruptions. Here we provide an overview of the distribution, shard concentration and geochemistry of these tephras to highlight the most important isochrones for addressing key dating issues. In particular, three horizons – Hekla‐1 (AD 1104), Öræfajökull (AD 1362) and Askja (AD 1875) – are found at a number of different locations in northern Europe and as such are valuable tie‐points for improving and validating chronological models and for synchronisation of records spanning the last 1000 years. In addition, we present new data identifying tephra from the Grímsvötn volcanic system within the Lomonosovfonna ice cap on Svalbard, demonstrating that some tephras have been transported 2000 km to as far north as 79° N along a northeasterly trajectory. This discovery highlights the potential for utilising tephrochronology as a correlation tool for palaeoarchives located in more northerly areas and the complex nature of fall‐out from different eruptions. Copyright © 2009 John Wiley & Sons, Ltd.