Strontium isotope characteristics (δ88/86Sr, 87Sr/86Sr) of Arima-type brines originated from slab-fluids
Strontium isotope characteristics (δ88/86Sr, 87Sr/86Sr) of Arima-type brines originated from slab-fluids
复制标题
板状流体华宇型卤水的锶同位素特征（δ88/86Sr、87Sr/86Sr）
DOI：
10.1029/2022gl100309
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发表时间：
2023
影响因子：
5.2
通讯作者：
Y. Terakado
中科院分区：
文献类型：
--
作者：
T. Kani;K. Misawa;N. Morikawa;K. Kazahaya;F. Kusuhara;S. Yoneda;Y. Terakado
在日本西南部的弧前，俯冲物质产生的板条流体迁移到地壳水平，表现为深层卤水。我们首次分析了高盐度非火山泉水中稳定的锶同位素，称为ARIMA型咸水，可能来自沿主要断裂上升的板条流体。咸水稳定的锶同位素组成为轻同位素(δ88/86Sr=0.122-0.157‰)，不同于当地基岩和近地表水。咸水的轻锶富集和放射成因特征反映了地壳中没有同位素叠加的板条流体的主要特征。ARIMA型卤水在弧前深度显示板岩流体特征，这与由弧熔岩估算的弧下深度板岩流体特征不同。ARIMA型卤水的特征是在浅层流体形成过程中，俯冲沉积物和锶同位素分馏的贡献较大。
In the southwest Japan forearc, slab‐fluids produced from subducted materials migrate to crustal levels and appear as deep‐seated brine. We have analyzed for the first‐time stable strontium isotopes in non‐volcanic spring water with high salinity, referred to as Arima‐type saline water that likely originate from slab‐fluid that upwelled along major faults. The stable strontium isotope compositions of the saline water are isotopically light (δ88/86Sr = 0.122–0.157‰) and different from those of local bedrock and near‐surface water. The light strontium‐enriched and radiogenic signature of the saline water reflects the primary characteristic of slab‐fluids without an isotopic overprint in the crust. The Arima‐type brines show signatures of slab‐fluids at forearc depth, which is different from the slab‐fluids at subarc depth estimated from arc lavas. The characteristic features of the Arima‐type brines are explained by a larger contribution of subducted sediments and strontium isotope fractionation during fluids generation at shallower depth.