Diverse magmatic effects of subducting a hot slab in SW Japan: Results from forward modeling
Diverse magmatic effects of subducting a hot slab in SW Japan: Results from forward modeling
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DOI：
10.1002/2013gc005132
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发表时间：
2014-03
期刊：
影响因子：
3.7
通讯作者：
J. Kimura;J. Gill;T. Kunikiyo;I. Osaka;Y. Shimoshioiri;M. Katakuse;S. Kakubuchi;T. Nagao;K. Furuyama;A. Kamei;H. Kawabata;J. Nakajima;P. V. van Keken;R. Stern
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文献类型：
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作者：
J. Kimura;J. Gill;T. Kunikiyo;I. Osaka;Y. Shimoshioiri;M. Katakuse;S. Kakubuchi;T. Nagao;K. Furuyama;A. Kamei;H. Kawabata;J. Nakajima;P. V. van Keken;R. Stern
为了响应菲律宾海板块年轻四国盆地的俯冲作用，整个新生代晚期日本西南部都爆发了弧岩浆。存在多种岩浆类型，包括洋岛玄武岩（OIB）、钾玄岩（SHO）、弧型碱性玄武岩（AB）、典型的亚碱性弧玄武岩（SAB）、高镁安山岩（HMA）和埃达克岩（ADK）。OIB爆发自日本海弧后盆地打开，而随后的弧岩浆伴随着四国盆地的俯冲。然而，那里的岩浆的起源与热俯冲有关的争论。使用新的主要和微量元素和Sr-Nd-Pb-Hf同位素分析的324个熔岩样品从7个第四纪火山，我们研究了岩浆套的成因条件，使用地球化学质量平衡模型，弧玄武岩模拟器版本4（ABS 4），使用这些数据来解决的参数，如压力/温度板脱水/熔融和板通量分数，压力和温度的地幔熔融。计算表明，这些岩浆起源于板片熔体，导致地幔橄榄岩熔融。这些套件的差异主要在于板坯熔体熔剂的质量分数，从SHO到AB、SAB、HMA再到ADK。地幔熔融的压力和温度以相同的顺序降低。套房不同其次是在板片熔体的源蚀变洋壳沉积物的比例。与热俯冲有关的非典型套件是由异常大的板片熔体质量分数和异常冷的地幔温度造成的。
In response to the subduction of the young Shikoku Basin of the Philippine Sea Plate, arc magmas erupted in SW Japan throughout the late Cenozoic. Many magma types are present including ocean island basalt (OIB), shoshonite (SHO), arc‐type alkali basalt (AB), typical subalkalic arc basalt (SAB), high‐Mg andesite (HMA), and adakite (ADK). OIB erupted since the Japan Sea back‐arc basin opened, whereas subsequent arc magmas accompanied subduction of the Shikoku Basin. However, there the origin of the magmas in relation to hot subduction is debated. Using new major and trace element and Sr‐Nd‐Pb‐Hf isotope analyses of 324 lava samples from seven Quaternary volcanoes, we investigated the genetic conditions of the magma suites using a geochemical mass balance model, Arc Basalt Simulator version 4 (ABS4), that uses these data to solve for the parameters such as pressure/temperature of slab dehydration/melting and slab flux fraction, pressure, and temperature of mantle melting. The calculations suggest that those magmas originated from slab melts that induced flux melting of mantle peridotite. The suites differ mostly in the mass fraction of slab‐melt flux, increasing from SHO through AB, SAB, HMA, to ADK. The pressure and temperature of mantle melting decreases in the same order. The suites differ secondarily in the ratio of altered oceanic crust to sediment in the source of the slab melt. The atypical suites associated with hot subduction result from unusually large mass fractions of slab melt and unusually cool mantle temperatures.