...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Contributions to Mineralogy and Petrology >Small volume andesite magmas and melt–mush interactions at Ruapehu, New Zealand: evidence from melt inclusions
【24h】

Small volume andesite magmas and melt–mush interactions at Ruapehu, New Zealand: evidence from melt inclusions

机译：新西兰鲁阿佩胡的少量安山岩岩浆和熔岩相互作用：来自熔岩包裹体的证据

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

Historical eruptions from Mt. Ruapehu (New Zealand) have been small (<0.001 km3 of juvenile magma) and have often occurred without significant warning. Developing better modelling tools requires an improved understanding of the magma storage and transport system beneath the volcano. Towards that end, we have analysed the volatile content and major element chemistry of groundmass glass and phenocryst-hosted melt inclusions in erupted samples from 1945 to 1996. We find that during this time period, magma has been stored at depths of ~2–9 km, consistent with inferences from geophysical data. Our data also show that Ruapehu magmas are relatively H2O-poor (<2 wt%) and CO2-rich (≤1,000 ppm) compared to typical arc andesites. Surprisingly, we find that melt inclusions are often more evolved than their transporting melt (as inferred from groundmass glass compositions). Furthermore, even eruptions that are separated by less than 2 years exhibit distinct major element chemistry, which suggests that each eruption involved magma with a unique ascent history. From these data, we infer that individual melt batches rise through, and interact with, crystal mush zones formed by antecedent magmas. From this perspective, we envision the magmatic system at Ruapehu as frequently recharged by small magma inputs that, in turn, cool and crystallise to varying degrees. Melts that are able to erupt through this network of crystal mush entrain (to a greater or lesser extent) exotic crystals. In the extreme case (such as the 1996 eruption), the resulting scoria contain melt inclusion-bearing crystals that are exotic to the transporting magma. Finally, we suggest that complex interactions between recharge and antecedent magmas are probably common, but that the small volumes and short time scales of recharge at Ruapehu provide a unique window into these processes.
机译：富士山的历史喷发鲁阿佩胡（新西兰）很小（<0.001 km3的青少年岩浆），经常发生而没有明显的警告。开发更好的建模工具需要更好地了解火山下面的岩浆储运系统。为此，我们分析了1945年至1996年喷发样品中的地下玻璃和隐晶系熔体夹杂物的挥发性含量和主要元素化学成分。我们发现，在这段时间内，岩浆的储藏深度约为2–9 km，与来自地球物理数据的推论一致。我们的数据还显示，与典型的弧山安山岩相比，鲁阿佩胡岩浆的H2O含量相对较低（<2 wt％）并且富含CO2（≤1,000ppm）。出乎意料的是，我们发现熔体夹杂物通常比其输送熔体更容易演化（从地基玻璃成分中推断）。此外，即使间隔不到两年的喷发也显示出独特的主要元素化学性质，这表明每次喷发都涉及具有独特上升历史的岩浆。从这些数据中，我们推断出各个熔体批次上升并与前岩浆形成的晶体糊状区相互作用。从这个角度来看，我们设想Ruapehu的岩浆系统会经常被小型岩浆输入所充能，进而使它们冷却和结晶成不同程度。能够通过这种晶体糊状网络爆发的熔体会（或多或少地）夹带异质晶体。在极端情况下（例如1996年的喷发），生成的熔渣中含有熔体夹杂的晶体，这些晶体对运输岩浆而言是奇特的。最后，我们建议补给与先前岩浆之间的复杂相互作用很常见，但是鲁阿佩胡的少量补给和短时间补给提供了进入这些过程的独特窗口。

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