Sediment-enriched adakitic magmas from the Daisen volcanic field, Southwest Japan
Sediment-enriched adakitic magmas from the Daisen volcanic field, Southwest Japan
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来自日本西南部大山火山田的富含沉积物的埃达克岩浆
DOI：
10.1002/ggge.20176
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
E.
中科院分区：
文献类型：
--
作者：
Feineman;M.;Moriguti;T.;Yokoyama;T.;Terui;S. and Nakamura;E.
第四纪日本西南弧是年轻的菲律宾海板块俯冲到欧亚大陆板块之下的产物。从日本西南弧喷发的岩浆属于通常被称为“埃达克岩”或“埃达克质岩浆”的一类岩浆。这些岩浆显示微量元素的证据与石榴石在深度的相互作用，并可能与俯冲蚀变洋壳的部分熔融。在整个日本海南部地区也发现了碱性玄武岩，与俯冲带几乎没有明显的联系。我们已经确定了主元素，微量元素和Sr，Nd，Pb和U-Th同位素组成的双峰套喷发的熔岩在戴森火山场在日本西南弧。这些岩浆由弱碱性玄武岩和钙碱性中间岩套组成，中间岩套之间的质量分数为10%。硅隙中间岩浆与石榴石相互作用的微量元素和同位素证据，与部分熔融的热，年轻的（120马）菲律宾海板块一致。戴森中间岩浆的放射性同位素特征与其它埃达克质岩浆不同，与南海海槽俯冲沉积物的显著贡献（约25%）一致。我们的数据表明，在戴森火山区喷发的玄武岩不是中间岩浆的母体，并含有少量的日本海碱性玄武岩中常见的EM 1-样地幔，但在戴森中间岩浆中不明显。
The Quaternary Southwest Japan Arc is a product of subduction of the hot, young Philippine Sea Plate beneath the Eurasian Continental Plate. The magmas erupted from the Southwest Japan Arc belong to a category of magmas commonly referred to as “adakites” or “adakitic magmas”. These magmas show trace element evidence for interaction with garnet at depth, and may be associated with partial melting of subducted altered oceanic crust. Also found throughout the southern Sea of Japan region are alkali basalts with little apparent connection to the subduction zone. We have determined major element, trace element, and Sr, Nd, Pb, and U‐Th isotopic compositions for a bimodal suite of lavas erupted at the Daisen volcanic field in the Southwest Japan Arc. These magmas consist of mildly alkaline basalts and a calcalkaline intermediate suite, separated by a ∼10 wt.% silica gap. The intermediate magmas show trace element and isotopic evidence for interaction with garnet, consistent with partial melting of the hot, young (∼20 Ma) Philippine Sea Plate. The Daisen intermediate magmas are distinct from other adakitic magmas in their radiogenic isotopic characteristics, consistent with a significant contribution (∼25%) from subducted Nankai Trough sediments. Our data suggest that the basalts erupted at the Daisen volcanic field are not parental to the intermediate magmas, and contain a small contribution of EM1‐like mantle common in Sea of Japan alkali basalts but not apparent in the Daisen intermediate magmas.