Water in Magmas: Experimental Constraints on the Stability of Hornblende in Basalts and Basaltic Andesites

岩浆中的水：玄武岩和玄武安山岩中角闪石稳定性的实验约束

• 批准号: 9706129
• 负责人: Ian S. Carmichael
• 金额: $ 20.74万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-15 至 2001-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9706129&HistoricalAwards=false
• 关键词: Water; Magmas; Experimental; Constraints; Stability

9706129 Carmichael Previous work has determined that the phenocryst assemblages of andesitic lavas in western Mexico are strongly influenced by the concentrations of water that the magmas contain. Basalts and basaltic andesites from central Mexico may contain hornblende phenocrysts and it is proposed to quantify the P-T conditions, together with the water concentration in the liquids, in the regimes in which hornblende is stable. In addition, phenocrysts of pyroxene and olivine, often without plagioclase, will be used to constrain the water concentrations in basalts and basaltic andesites without hornblende. Ferric-ferrous ratios in the hornblendes will be calibrated with oxygen fugacity in an internally heated pressure vessel in which the rapid quench preserves the liquid as a glass. In addition, the geological age and environment of andesites-basalts in central Mexico are so poorly known that mapping and sampling will be completed in Zitacuaro region of Michoacan, Mexico.

9706129卡迈克尔先前的工作已经确定，墨西哥西部安山质熔岩的斑晶组合强烈地受到岩浆所含水分浓度的影响。来自墨西哥中部的玄武岩和玄武安山岩可能含有角闪石斑晶，建议在角闪石稳定的制度中量化P-T条件以及液体中的水浓度。此外，辉石和橄榄石的斑晶，往往没有斜长石，将被用来限制水的浓度在玄武岩和玄武安山岩没有角闪石。角闪石中的铁-铁比将在内部加热的压力容器中用氧逸度进行校准，其中快速淬火将液体保持为玻璃状。此外，墨西哥中部安山岩-玄武岩的地质时代和环境知之甚少，因此将在墨西哥米霍坎的Zitacuaro地区完成制图和取样。