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

9706129 Carmichael先前的工作已经确定，墨西哥西部安山岩熔岩的斑晶组合受到岩浆所含水浓度的强烈影响。墨西哥中部的玄武岩和玄武岩安山岩可能含有角闪石斑晶，并提出在角闪石稳定的情况下，定量P-T条件以及液体中的水浓度。此外，通常不含斜长石的辉石和橄榄石的斑晶将被用来限制不含角闪石的玄武岩和玄武岩安山岩中的水浓度。角闪石中的铁-铁比率将在内部加热的压力容器中用氧逸度进行校准，其中快速淬火使液体保持玻璃状。此外，由于对墨西哥中部安山岩-玄武岩的地质年代和环境知之甚少，因此将在墨西哥米却肯州的Zitacuaro地区完成测绘和采样。

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.