Abundance and distribution of water, carbon and sulfur in the glassy rims of submarine pillow basalts
Abundance and distribution of water, carbon and sulfur in the glassy rims of submarine pillow basalts
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DOI：
10.1016/0016-7037(78)90003-0
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发表时间：
1978-06
影响因子：
5
通讯作者：
J. Delaney;D. W. Muenow;D. G. Graham
中科院分区：
文献类型：
--
作者：
J. Delaney;D. W. Muenow;D. G. Graham
斑晶，含有玻璃蒸汽包裹体淬火在拉斑玄武岩的海底枕状玄武岩的玻璃边缘从扩展中心和夏威夷，质谱分析表明，从热爆裂后的包裹体释放的水是远远小于从包围相同斑晶的基质玻璃的等效体积释放。如果释放的水代表喷发时两种类型的玻璃（包体和基质）中淬灭的水，那么包体所含的水远远少于斑晶周围的岩浆。这样的条件是一致的水贫化源质量的玄武岩和水的涌入到熔体后，夹杂物的形成，但在海底淬火。马里亚纳弧间盆地拉斑玄武岩枕状玄武岩斑晶内的玻璃蒸汽包体释放了丰富的水，即使相邻的基质玻璃只含有50%以上的水比夏威夷基质玻璃。马里亚纳枕缘基质玻璃的含水量非常接近实验饱和值。相比之下，来自MORs和夏威夷的基质玻璃明显低于水饱和度。这些玻璃中的囊泡是最合理的占CO2占主导地位的气相，因为这些玄武岩玻璃的CO2含量接近实验的溶解度极限。玻璃蒸汽夹杂物斑晶从相同的枕头似乎含有更多的CO 2比相邻的基质玻璃，这意味着一个CO 2为主的蒸汽开发和脱气喷发前和夹杂物形成后。水的注入和CO 2的脱气联合收割机使海底玄武岩玻璃的CO 2（CO 2+ H 2 O）比值成为岩浆源区的最小值。内含物玻璃的硫含量通常与封闭基质玻璃的硫含量非常相似。
Mass spectrometric analyses of phenocrysts, containing glass-vapor inclusions quenched in glassy rims of tholeiitic submarine pillow basalts from spreading centers and Hawaii, indicate that water released from the inclusions upon thermal decrepitation is much less than is released from equivalent volumes of the matrix glass enclosing the same phenocrysts. If water released represents water quenched in the two types of glass (inclusion and matrix) at the time of eruption, then the inclusions contained far less water than the magma surrounding the phenocrysts. Such a condition is consistent with a water depleted source mass for the basalts and an influx of water into the melt after inclusion formation but before quenching at the ocean floor. Glass-vapor inclusions within phenocrysts in tholeiitic pillow basalts from the Marianas Interarc Basin released abundant water even though the adjacent matrix glasses contain only 50% more water than Hawaiian matrix glasses. Water contents of matrix glasses from the Marianas pillow rims are very close to experimental saturation values. In contrast, matrix glasses from MORs and Hawaii are distinctly below water saturation. Vesicles in these glasses are most reasonably accounted for by a CO 2-dominated vapor phase, because CO 2 contents of those basalt glasses closely approximate experimental solubility limits. Glass-vapor inclusions in phenocrysts from the same pillows appear to contain more CO 2 than adjacent matrix glasses, implying that a CO 2-dominated vapor developed and outgassed prior to eruption and after inclusion formation. Water influx and CO 2 degassing combine to make the CO 2 (CO 2+ H 2 O) ratio of seafloor basalt glasses a minimum value for the magma source mass. The sulfur content of the inclusion glasses is normally very similar to that of the enclosing matrix glass.