Experimental investigation of the S and S-isotope distribution between H2O-S ± Cl fluids and basaltic melts during decompression
Experimental investigation of the S and S-isotope distribution between H2O-S ± Cl fluids and basaltic melts during decompression
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DOI：
10.1016/j.chemgeo.2014.11.012
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发表时间：
2015-01-30
期刊：
影响因子：
3.9
通讯作者：
Goettlicher, Joerg
中科院分区：
文献类型：
--
作者：
Fiege, Adrian;Holtz, Francois;Goettlicher, Joerg
在400~70 Mpa范围内，对玄武岩熔体和共生流体之间的硫(5)、硫(5)和5-同位素分离子进行了减压实验。用含3~7wt%水(H2O)、300~1200ppm S(H2O)、0~3600ppm氯(Cl)的玄武岩玻璃作熔体，熔体中的氧化镁含量接近1wt%(贫镁玄武岩)。或类似于10wt.%(碱性玄武岩)探讨玄武岩体系成分变化对S和S同位素流体-熔体分布的可能作用。实验在内热压力容器(IHPV)中进行，温度为1050“C至1250℃，可变氧逸度fO(2)；在恒定减压速率(R)为0.1 Mpa/s的条件下，从与QFm相似的对数(fO(2)/bar)到类似于QFm+4的QFm+4.在减压后终压(P)和温度(T)下的热处理时间(t(A))从0到5.5h变化，以研究液-熔平衡过程.减压过程中熔体中的硫和H2O含量显著降低，而氯含量I几乎保持不变.水和氯的含量随t(A)的变化不大，而S的浓度随t(A)=2 h略有下降。
Decompression experiments (from 400 to 70 MPa) were conducted Lo invesligale sulfur (5) dislaibulion and 5-isotope fraclionalion between basaltic melts and coexisling fluids. Volaffle-bearing [similar to 3 to similar to 7 wt.% water (H2O), similar to 300 to similar to 1200 ppm S,0 to similar to 3600 ppm chlorine (Cl)] basaltic glasses were used as slailing mareLials.The MgO conlent in the melt was effher similar to 1 wt.% (Mg poor basalt.) or similar to 10 wt.% (alkali basalt.) toinvesligale he possible role of compositional changes in basaltic sysLems on fluid -melt distribution of S and S-isoLopes. The experiments were performed in internally heated pressure vessels (IHPV) at 1050"C to 1250 C, variable oxygen fugacities fO(2); ranging from log(fO(2)/bar) similar to QFM to similar to QFM + 4. QFM = quartz-fayalite-magnetite buffer) and at a constant decompression rate (r) of 0.1 MPa/s.The annealing time (t(A)) at final pressure (p) and temperature (T) after decompression was varied from 0 to 5.5 h to study the fluid-melt equilibration process.Sulfur and H2O contents in the melt decreased significantly during decompression, while the Cl contents I emained almost constant. No changes in H2O and Cl content were observed with t(A), while S concentrations decreased slightly with t(A) = 2 h. The MgO (similar to 1 to similar to 10 wt.%), H2O (similar to 3 to similar to 7 wt.%) and Cl contents (