Arc Basalt Simulator version 2, a simulation for slab dehydration and fluid‐fluxed mantle melting for arc basalts: Modeling scheme and application
Arc Basalt Simulator version 2, a simulation for slab dehydration and fluid‐fluxed mantle melting for arc basalts: Modeling scheme and application
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DOI：
10.1029/2008gc002217
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发表时间：
2009-09
期刊：
影响因子：
3.7
通讯作者：
J. Kimura;B. Hacker;P. V. van Keken;H. Kawabata;Takeyoshi Yoshida;R. Stern
中科院分区：
文献类型：
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作者：
J. Kimura;B. Hacker;P. V. van Keken;H. Kawabata;Takeyoshi Yoshida;R. Stern
会聚边缘岩浆通常具有地球化学特征，包括高浓度的大离子亲石元素;贫化的重稀土元素和高场强元素;以及不同的放射成因Sr，Pb和Nd同位素组成。这些都归因于亏损地幔橄榄岩熔融的流体或熔融来自俯冲洋壳。高Mg #玄武岩和高Mg #安山岩被推断为构成了大部分与俯冲有关的原生岩浆，可能是由地幔橄榄岩的流体或熔体熔融产生的。不同的弧之间发现俯冲板片的贡献的差异似乎主要是由热结构控制。冷板产生流体，热板产生熔体。最近的实验研究和热力学模型更好地约束了地幔楔状变质和熔融、地幔楔状熔融和地幔板片熔融反应过程中板片组分的相岩石学。实验结果也限制了这些过程中许多元素的行为。此外，地球动力学模型允许越来越现实的，在俯冲板和地幔楔的温度和压力的定量建模。这些进展共同使生成的正演模型来解释弧岩浆地球化学。Arc Basalt Simulator（ABS）第2版（ABS 2）使用基于Excel®电子表格的计算器来预测板状流体和由地幔楔橄榄岩的开放系统流体熔融产生的弧玄武岩岩浆中不相容元素和Sr-Nd-Pb同位素组成的分配。ABS 2模型旨在模拟相对寒冷的俯冲带中的高Mg #玄武岩地球化学。介绍了ABS 2的模拟方案，并将其应用于原始弧岩浆。
Convergent margin magmas typically have geochemical signatures that include elevated concentrations of large‐ion lithophile elements; depleted heavy rare earth elements and high field strength elements; and variously radiogenic Sr, Pb, and Nd isotopic compositions. These have been attributed to the melting of depleted mantle peridotite by the fluxing of fluids or melts derived from subducting oceanic crust. High Mg # basalts and high Mg # andesites are inferred to make up the bulk of subduction‐related primary magmas and may be generated by fluid or melt fluxing of mantle peridotite. The difference in contributions from the subducted slab found among various arcs appears to be mostly controlled by thermal structure. Cold slabs yield fluids, and hot slabs yield melts. Recent experimental studies and thermodynamic models better constrain the phase petrology of the slab components during prograde metamorphism and melting, mantle wedge melting, and mantle slab melt reaction. Experimental results also constrain the behavior of many elements in these processes. In addition, geodynamic models allow increasingly realistic, quantitative modeling of the temperature and pressure in the subducted slab and mantle wedge. These developments together enable generation of forward models to explain arc magma geochemistry. The Arc Basalt Simulator (ABS) version 2 (ABS2) uses an Excel® spreadsheet‐based calculator to predict the partitioning of incompatible element and Sr‐Nd‐Pb isotopic composition in a slab‐derived fluid and in arc basalt magma generated by an open system fluid‐fluxed melting of mantle wedge peridotite. The ABS2 model is intended to simulate high Mg # basalt geochemistry in relatively cold subduction zones. The modeling scheme of ABS2 is presented and is applied to primitive arc magmas.