• 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 Research2012V243-244NOCT,15 >The evolution of volcanic systems following sector collapse
【24h】

The evolution of volcanic systems following sector collapse

机译：部门崩溃后火山系统的演变

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

Sector collapses affect volcanic edifices across all tectonic settings and involve a rapid redistribution of mass, comparable in scale to the largest magmatic eruptions. The eruptive behaviour of a volcano following sector collapse provides a test of theoretical relationships between surface loading and magma storage, which imply that collapse-driven unloading may lead to changes in eruption rate and erupted magma compositions. Large sector collapses are infrequent events globally, with all historical examples being relatively small in comparison to many of the events documented in the geological record. As a result, exploration of the impacts of sector collapse on eruptive behaviour requires detailed investigation of prehistoric collapses, but this is often hindered by poorly-resolved stratigraphic relationships and dating uncertainties. Nevertheless, observations from a number of volcanoes indicate sharp changes in activity following sector collapse. Here, a global synthesis of studies from individual volcanoes, in both arc and intraplate settings, is used to demonstrate a number of common processes in post-collapse volcanism. Multiple examples from large (>5 km(3)) sector collapses in arc settings show that collapse may be followed by compositionally anomalous, large-volume and often effusive eruptions, interpreted to originate via disruption of a previously stable, upper-crustal reservoir. These anomalous eruptions highlight that magma compositions erupted during periods of typical (i.e. unperturbed by sector collapse) volcanism may not be representative of the range of compositions stored within a vertically extensive crustal reservoir. If eruptible magma is not present, upper-crustal reservoirs may rapidly solidify following collapse, without further eruption, allowing more mafic compositions to ascend to the surface with only limited upper-crustal modification, resulting in edifice regrowth at temporarily elevated eruption rates. Subsequent re-establishment of an upper-crustal reservoir further supports a relationship between surface loading and crustal storage, but long-term chemical and mineralogical differences between pre- and post-collapse evolved magmas imply that a newly-developed reservoir can overprint the influence of a preceding reservoir, forming a spatially and compositionally distinct plumbing system. These broad patterns are replicated in intraplate settings, despite differences in scale and melting processes; current evidence suggests that post-collapse evolution of intraplate volcanoes can be explained by unloading-induced destabilisation of the magma plumbing system, rather than increased melt production. What emerges from an apparently diverse set of observations is a systematic behaviour that strongly supports a coupling between edifice growth and magma ascent, storage and pressurisation. Eruption rates, erupted compositions, and the style of volcanism at any particular system may thus be modulated from the surface, and long-term shifts in surface behaviour may occur without any changes in the deep parts of magmatic systems. Observations of sharp post-collapse changes in erupted compositions, including the ascent of primitive mafic magmas, also require a crystal-dominated mid- to upper-crustal reservoir, consistent with recent models of crustal magmatic systems. (C) 2019 Elsevier B.V. All rights reserved.
机译：扇形塌陷影响着所有构造环境中的火山构造，并涉及质量的快速重新分布，其规模可与最大的岩浆喷发相媲美。扇形坍塌之后火山的喷发行为提供了对地表负荷与岩浆储藏之间理论关系的检验，这意味着由塌陷驱动的卸荷可能导致喷发率的变化和岩浆成分的喷发。在全球范围内，大型部门倒塌是罕见的事件，与地质记录中记录的许多事件相比，所有历史例子都相对较小。结果，要探索扇形坍塌对喷发行为的影响，需要对史前的塌陷进行详细的研究，但这通常由于解析度差的地层关系和年代不确定性而受到阻碍。然而，从许多火山中观察到的数据表明，扇形坍塌后活动发生了急剧变化。在这里，对弧和板内设置中单个火山的研究进行了全球综合，用于证明崩溃后火山活动中的许多常见过程。弧形环境中大型（> 5 km（3））塌陷的多个例子表明，塌陷后可能会发生成分异常，大体积且通常为喷发性喷发，这被解释为是由先前稳定的上地壳储层的破坏引起的。这些异常喷发突显出在典型的火山爆发期间（即不受扇形塌陷扰动）喷发的岩浆成分可能无法代表垂直扩展的地壳储层中存储的成分范围。如果不存在可喷出的岩浆，塌陷后上地壳储层可能会迅速凝固，而不会进一步喷发，仅在有限的上地壳变质作用下，更多的镁铁质成分就可以上升到地表，从而导致喷发速率暂时升高，从而导致大厦再生。随后重建上地壳储层进一步支持了地表负荷与地壳储藏之间的关系，但是坍塌前后岩浆之间的长期化学和矿物学差异暗示着新开发的储层可以掩盖火山作用的影响。前一个水库，形成一个在空间和成分上截然不同的管道系统。尽管规模和融化过程有所不同，但这些宽广的模式仍在板内设置中得以复制。目前的证据表明，板岩内火山坍塌后的演化可以通过岩浆管道系统的卸载引起的不稳定来解释，而不是通过增加熔体产量来解释。从一系列显然不同的观察结果中得出的是一种系统行为，强烈支持了建筑物生长与岩浆上升，储存和增压之间的耦合。因此，可以从地表调节任何特定系统的喷发速率，喷发的成分以及火山的样式，并且在不对岩浆系统的深部进行任何改变的情况下，可以发生地表行为的长期变化。观测到喷发后的急剧坍塌变化，包括原始铁镁质岩浆的上升，也需要一个以晶体为主的中上地壳储层，这与最近的地壳岩浆系统模型相一致。 （C）2019 Elsevier B.V.保留所有权利。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
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