Preeruptive Stratification of the Oruanui Rhyolitic Magma, Taupo Volcanic Center, New Zealand

新西兰陶波火山中心 Oruanui 流纹岩浆喷发前分层

• 批准号: 0106327
• 负责人: Alfred Anderson
• 金额: $ 20.26万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0106327&HistoricalAwards=false
• 关键词: Preeruptive; Stratification; Oruanui; Rhyolitic; Magma

AndersonEAR-0106327The proposed research focusses on the Orunaui rhyolitic ash-flow tuff, a geologically young and contrasting counterpart to the Bishop Tuff. We plan to test whether the preeruptive Oruanui magma was stably stratified. If the unsystematically erupted Oruanui pumice compositions nevertheless derive from a density stratified magma body, then the case will be strengthened that many big bodies of silicic magma probably achieve a stable density stratification by natural processes of magma formation, emplacement, crystallization and exsolution of gas. We will study the preeruptive state of the magma by studying inclusions and reentrants of glass in quartz and other phenocrysts, because these plausibly preserve a record of the preeruptive conditions, little modified by eruptive decompression, gas exsolution and crystallization. Our study will help understand the formation of silicic planetary crusts as well as the behavior of active bodies of silicic magma including their propensity for eruption and interactions with geothermal systems, which are sites of ore deposition and energy production.

安德森-0106327拟议的研究重点是Orunaui流纹岩灰流凝灰岩，一个地质年轻和对比对应的主教凝灰岩。我们计划测试喷发前的Oruanui岩浆是否稳定分层。 如果非系统喷发的Oruanui浮石成分仍然来自密度分层的岩浆体，那么将加强许多大的岩浆体可能通过岩浆形成、侵位、结晶和气体出溶的自然过程实现稳定的密度分层的情况。我们将通过研究石英和其他斑晶中的玻璃包裹体和重入体来研究岩浆的喷发前状态，因为这些物质可以保留喷发前条件的记录，几乎不受喷发减压、气体出溶和结晶的影响。我们的研究将有助于了解行星地壳的形成以及岩浆活动体的行为，包括它们的喷发倾向以及与地热系统的相互作用，地热系统是矿石沉积和能源生产的场所。