Chemical fluxes in the Tonga Subduction Zone: Evidence from the Southern Lau Basin
Chemical fluxes in the Tonga Subduction Zone: Evidence from the Southern Lau Basin
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汤加俯冲带的化学通量：来自劳盆地南部的证据
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
J. Erzinger
中科院分区：
文献类型：
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作者：
W. Bach;E. Hegner;J. Erzinger
劳盆地南部瓦卢法岭（VFR）火山玻璃的化学和同位素数据与附近汤加弧的火山岩成分非常相似。VFR中最原始的玄武岩被用来重建原始岩浆成分，据信这反映了大块地壳的成分。估计了瓦鲁法岭的岩浆生产率（0.7 - 1.5×106 kg/a/m），并根据这些值和原生岩浆成分计算了各种元素的化学通量。VFR熔岩的化学和同位素组成与俯冲蚀变洋壳和沉积物中流体可溶元素的释放完全一致。质量平衡计算表明蚀变玄武岩基底作为超俯冲带岩石中H2O、K、Rb、Cs、Sr、U和Pb的来源的重要作用。
Chemical and isotopic data for volcanic glasses from the Valu Fa Ridge (VFR) in the southern Lau Basin closely resemble the composition of volcanics from the nearby Tonga arc. The most primitive basalts from the VFR were used to reconstruct the primary magma composition which is believed to reflect the composition of the bulk crust. The magma production rate at the Valu Fa Ridge was estimated (0.7−1.5×106 kg/a/m), and chemical fluxes of various elements have been calculated based on these values and the primary magma composition. The chemical and isotopic composition of VFR lavas is totally consistent with the release of fluid‐soluble elements from the subducting altered oceanic crust and sediments. Mass balance calculations indicate the important role of the altered basaltic basement as a source of H2O, K, Rb, Cs, Sr, U, and Pb in supra‐subduction zone rocks.