Three new distal tephras in sediments spanning the Last Glacial–Interglacial Transition in Scotland
Three new distal tephras in sediments spanning the Last Glacial–Interglacial Transition in Scotland
复制标题
苏格兰末次冰期-间冰期过渡期间沉积物中的三个新的远端火山灰
DOI：
10.1002/jqs.1066
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发表时间：
2007
影响因子：
2.3
通讯作者：
S. Pyne‐O'Donnell
中科院分区：
文献类型：
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作者：
S. Pyne‐O'Donnell
在内赫布里底群岛和苏格兰大陆的一些湖泊中发现了三个新的微火山岩。其中一个在地层学上位于格陵兰岛1号冰间（GI‐1）的中部，被命名为Penifiler火山灰。它是流纹岩，具有与博罗博尔火山灰非常相似的地球化学特征，博罗博尔火山灰也出现在本文报道的三个层序中，但靠近GI-1的下边界。第二个在地层上出现在早全新世Saksunarvatn火山灰下面，被命名为Ashik火山灰。这火山灰是地球化学双峰，与流纹质成分相媲美的An Druim火山灰，发生在全新世后期，和玄武岩成分，这是类似的Saksunarvatn灰。第三个火山点出现在Saksunarvatn火山灰之上，暂时被命名为Breakish Tephra。在几个地点对这些新的火山灰岩所证明的一致的地点间相关性增强了区域火山灰地层框架，并增加了GI-1和全新世早期古环境事件的相关性。然而，在地层和时间上接近的多个具有相似地球化学性质的火山灰的出现，对必须进行火山灰地层调查的严格性有影响。版权所有© 2006约翰威利父子有限公司。
Three new microtephras are reported from a number of lake sites from the Inner Hebrides and Scottish mainland. One occurs stratigrapically in the middle of Greenland Interstadial 1 (GI‐1) and has been named the Penifiler Tephra. It is rhyolitic and possesses a geochemical signature that is very similar to that of the Borrobol Tephra, which also occurs in three of the sequences reported here, but which lies close to the lower boundary of GI‐1. The second occurs stratigraphically in the early Holocene below the Saksunarvatn Ash and is named the Ashik Tephra. This tephra is geochemically bimodal, with a rhyolitic component comparable to the An Druim Tephra that occurs later in the Holocene, and a basaltic component which is similar to the Saksunarvatn Ash. A third tephra occurs stratigraphically above the Saksunarvatn Ash and is provisionally named the Breakish Tephra. The consistent inter‐site correlation demonstrated for these new tephras at several sites enhances the regional tephrostratigraphic framework, and increases the potential for correlating palaeoenvironmental events during GI‐1 and the early Holocene. However, the occurrence of multiple tephras with similar geochemistry in close stratigraphic and temporal proximity has implications for the rigour with which tephrostratigraphic investigations must be performed. Copyright © 2006 John Wiley & Sons, Ltd.