Chemical Evolution of High-Temperature Silicic Magmas

高温硅质岩浆的化学演化

• 批准号: 0000926
• 负责人: Hanna Nekvasil
• 金额: $ 13.25万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0000926&HistoricalAwards=false
• 关键词: Chemical; Evolution; Temperature; Silicic; Magmas

NekvasilEAR-0000926Experiments simulating step-wise fractional crystallization will be continued on natural alkalic magmas ranging from basalts to rhyolite that are found world-wide on ocean islands and in continental hotspot and rifted regions as both volcanic and plutonic suites. These experiments will determine if crystal fractionation can play a dominant role in generating the compositional diversity of magmas in such suites, and if so, under which conditions of pressure, dissolved volatile content, and oxygen fugacity this fractionation may have taken place. Such information is invaluable for placing constraints on the thermal and compositional profiles of the mantle and lower crust and on magma diversification processes in general. Furthermore, since silica-rich lavas of quartz-oversaturated alkalic suites are highly volatile-rich and such volatiles play a major role in volcanic explosivity, experimental data on the increase of magmatic volatile content during fractionation of water-bearing minerals is directly applicable to the evaluation of potential volcanic hazards.

NekvasilEAR-0000926将继续对从玄武岩到流纹岩的天然碱性岩浆进行分步分离结晶的模拟实验，这些岩浆在世界各地的海洋岛屿以及大陆热点和裂谷地区作为火山和深成岩套被发现。这些实验将确定晶体分馏是否在这类岩套中产生岩浆成分多样性方面起主导作用，如果是的话，这种分馏可能是在什么压力、溶解挥发分含量和氧逸度条件下发生的。这些信息对于限制地幔和下地壳的热和成分分布以及一般的岩浆多样化过程是非常宝贵的。此外，由于石英-过饱和碱性岩套的富硅熔岩具有高度的富挥发性，这些挥发分在火山爆炸性中起着主要作用，因此，含水矿物分馏过程中岩浆挥发分含量增加的实验数据直接适用于潜在的火山灾害评价。