...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Volcanology and Geothermal Research >Highly explosive eruption of the monogenetic 8.6 ka BP La Vache et Lassolas scoria cone complex (Chaine des Puys, France)
【24h】

Highly explosive eruption of the monogenetic 8.6 ka BP La Vache et Lassolas scoria cone complex (Chaine des Puys, France)

机译：单基因8.6 ka BP La Vache和Lassolas scoria锥体复合体的爆发性爆发（法国Chaine des Puys）

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The eruption of the trachy-basaltic La Vache and Lassolas cone complex was the youngest eruption (ca. 8.6 ka BP) and one of the most violent in the Chaine des Puys, France. Here we present field data and results of grain size, componentry and clast density measurements of different layers of the widespread tephra deposit that is associated with this cone-forming eruption. Our data indicates five main eruption phases comprising a vent opening phase, a second sustained highly explosive phase, a third and fourth violent Strombolian phase and a fifth dominantly effusive phase. The layer formed by the opening phase is rich in lithic material, which was previously considered to be the result of phreatomagmatic activity. The data presented here on the componentry and textures of the pyroclastic material contradict this hypothesis. We propose instead that the material of the basal layer results from fragmentation caused by the explosion of a first arriving gas-dominated phase. The variations in eruption intensity during the main eruption phases are interpreted here to be the result of gas segregation within the plumbing system and fluxes in the magma ascent rate during the eruption. Significant amount of gas segregation is indicated by the deposition of both gas-poor and gas-rich material and by the presence of plate tephra. This is also supported by the simultaneous ejection of tephra and lava from both cones during most of the explosive activity. We suggest that gas segregation occurred within shallow intrusions and that fresh ascending material in the main conduit mixed with degassed material that flow back into the conduit from the intrusion before fragmentation. The interaction of the ascending magma and the opening of intrusions may have controlled the evolution and explosivity of the eruption. The high explosivity at the beginning of the eruption and the wide dispersal area, demonstrate that scoria cone eruptions in monogenetic fields can impose a major threat to the population and infrastructures nearby as these events may occur with little warning, and therefore research on this kind of eruptions is of a major importance to better understand the processes driving these events. (C) 2016 Elsevier B.V. All rights reserved.
机译：在法国Chaine des Puys，松动的玄武岩La Vache和Lassolas锥群的喷发是最年轻的喷发（约8.6 ka BP），也是最猛烈的喷发之一。在这里，我们介绍了田野数据以及与这种成锥状喷发有关的广泛分布的提夫拉沉积物不同层的粒度，成分和碎屑密度测量结果。我们的数据表明，有五个主要的喷发阶段，包括喷口打开阶段，第二个持续的高爆炸性阶段，第三和第四次猛烈的Strombolian阶段以及第五个主要喷发阶段。由开放相形成的层富含板岩材料，这以前被认为是发岩作用的结果。此处介绍的有关火山碎屑物质的组成和质地的数据与该假设相矛盾。相反，我们建议基底层的材料是由第一个到达的以气体为主的相爆炸引起的碎裂产生的。在这里，主要喷发阶段喷发强度的变化被解释为是管道系统内气体偏析和喷发期间岩浆上升速率通量的结果。气体贫乏和气体富集物质的沉积以及平板气溶胶的存在表明大量的气体偏析。在大多数爆炸活动中，同时从两个圆锥体中喷出的提夫拉和熔岩也支持了这一点。我们认为，气体隔离现象发生在浅层侵入体中，主导管中的新鲜上升物质与脱气物质混合在一起，然后在破碎之前从侵入体流回到导管中。上升岩浆和侵入体的相互作用可能已经控制了喷发的演化和爆发性。喷发开始时的高爆炸性和广泛的散布区域表明，单相场中的锥喷发可能对附近的人口和基础设施构成重大威胁，因为这些事件可能很少发生预警，因此需要对此类型进行研究爆发对于更好地了解驱动这些事件的过程至关重要。 （C）2016 Elsevier B.V.保留所有权利。

著录项

相似文献

  • 外文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号