Experimental phase equilibria constraints on pre‐eruptive storage conditions of the Soufriere Hills magma
Experimental phase equilibria constraints on pre‐eruptive storage conditions of the Soufriere Hills magma
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苏弗里耶尔山岩浆喷发前储存条件的实验相平衡约束
DOI：
10.1029/98gl00856
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发表时间：
1998
影响因子：
5.2
通讯作者：
R. Sparks
中科院分区：
文献类型：
--
作者：
J. Barclay;M. Rutherford;M. Carroll;M. Murphy;J. Devine;J. Gardner;R. Sparks
新的实验结果被用来约束的P，T，X（H2O）条件的苏弗里埃山岩浆上升和喷发之前。该实验是在1996年1月喷发的粉状安山岩上进行的，fO2相当于NNO+1，PH 2O，温度范围为50至200 MPa和800至940°C。角闪石在PH2O >115 MPa和温度<875°C时稳定。石英仅在低温下和在PH2O >115 MPa下高度结晶（T <840°C，残余熔体中>72重量% SiO2）后才变得稳定。对新近喷发样品中石英和斜长石中的流纹质玻璃包裹体的分析表明，熔融水含量为4.27± 0.54wt%H2O，CO2含量<60 ppm。因此，演化的苏弗里埃山岩浆在压力<130 MPa时是H2O饱和的。
New experimental results are used to constrain the P, T, X(H2O) conditions of the Soufriere Hills magma prior to ascent and eruption. The experiments were performed on a powdered andesite erupted in January, 1996, at an fO2 corresponding to ∼NNO+1 with PH2O and temperatures in the range 50 to 200 MPa and 800 to 940°C. Amphibole is stable at PH2O >115 MPa and temperatures <875°C. Quartz only becomes stable at low temperatures and after high degrees of crystallization (T <840°C, >72 wt% SiO2 in residual melt) at PH2O >115 MPa. Analyses of rhyolitic glass inclusions in quartz and plagioclase from recently erupted samples indicate melt water contents of 4.27±0.54 wt% H2O and CO2 contents <60 ppm. The evolved Soufriere Hills magma would therefore be H2O‐saturated at pressures <130 MPa.