INFRARED SPECTROSCOPIC MEASUREMENTS OF CO2 AND H2O IN JUAN-DE-FUCA RIDGE BASALTIC GLASSES
INFRARED SPECTROSCOPIC MEASUREMENTS OF CO2 AND H2O IN JUAN-DE-FUCA RIDGE BASALTIC GLASSES
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DOI：
10.1016/0012-821x(88)90114-8
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发表时间：
1988-09-01
影响因子：
5.3
通讯作者：
DELANEY, JR
中科院分区：
文献类型：
--
作者：
DIXON, JE;STOLPER, E;DELANEY, JR
用红外光谱法测定了胡安·德富卡海岭及其邻近海山玄武岩玻璃中溶解H2O和CO2的含量。CO2含量范围约为45至360 ppm（重量），碳酸根离子络合物是溶解碳的唯一可检测形式。在给定的深度喷发的样品表现出大范围的溶解CO2含量，我们解释为变量的脱气的结果。在每个深度的最低CO2含量是在合理的协议与实验确定的CO2溶解度曲线玄武岩在低压。所有的玻璃与CO2值高于实验确定的溶解度在喷发深度过饱和，因为不完全脱气。最高的CO2含量在空间上与每个脊段的当地地形高点。来自相对较深地区的熔岩在从岩浆房上升或在岩脉或海底熔岩流的侧向流动期间可能有更大的机会脱气。观测到的最高CO2浓度来自轴向海山，并导致估计在脊轴以下2.7 km的岩浆房的最小深度。H2O含量从0.07到0.48 wt.%不等，其中羟基是溶解水的唯一可检测形式。水含量呈正相关的FeO*/MgO和最高的水含量被发现在不相容的元素富集奋进段熔岩。水与其他不相容元素的比例变化表明，在部分熔融期间，水具有与La相似的体积分配系数（D = 0.01）。
Dissolved H2O and CO2contents in basaltic glasses from the Juan de Fuca Ridge and neighboring seamounts were determined by infrared spectroscopy. CO2contents range from about 45 to 360 ppm by weight, with carbonate ion complexes the only detectable form of dissolved carbon. Samples erupted at a given depth exhibit a large range in dissolved CO2contents that we interpret to be the result of variable amounts of degassing. The lowest CO2contents at each depth are in reasonable agreement with the experimentally determined CO2solubility curve for basalt at low pressures. All glasses with CO2values higher than the experimentally determined solubility at the eruption depth are oversaturated because of incomplete degassing. The highest CO2contents are spatially associated with the local topographic highs for each ridge segment. Lavas from relatively deep areas may have had greater opportunity to degas during ascent from a magma chamber or during lateral flow in dikes or seafloor lava flows. The highest observed CO2concentrations are from the axial seamount and lead to an estimate of a minimum depth to the magma chamber of 2.7 km beneath the ridge axis.H2O contents vary from 0.07 to 0.48 wt.%, with hydroxyl groups the only detectable form of dissolved water. Water contents correlate positively with FeO*/MgO and the highest water contents are found in the incompatible element-enriched Endeavour segment lavas. Variations in ratios of water to other incompatible elements suggest that water has a bulk partition coefficient similar to La during partial melting (D ∼ 0.01).