Lateral magma intrusion from a caldera-forming magma chamber: Constraints from geochronology and geochemistry of volcanic products from lateral cones around the Aso caldera, SW Japan
Lateral magma intrusion from a caldera-forming magma chamber: Constraints from geochronology and geochemistry of volcanic products from lateral cones around the Aso caldera, SW Japan
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来自形成火山口的岩浆房的侧向岩浆侵入：来自日本西南部阿苏火山口周围侧锥体的火山产物的地质年代学和地球化学的约束
DOI：
10.1016/j.chemgeo.2013.06.003
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发表时间：
2013
期刊：
影响因子：
3.9
通讯作者：
J.
中科院分区：
文献类型：
--
作者：
Miyoshi;M.;Shinmura;T.;Sumino;H.;Sano;T.;Miyabuchi;Y.;Mori;Y.;Inakura;H.;Furukawa;K.;Uno;K.;Hasenaka;T.;Nagao;K.;Arakawa;Y. and Yamamoto;J.
本文研究了日本九州中部阿索火山口周围的侧向岩浆锥和熔岩的K-Ar年龄以及熔岩单元的岩石学和地球化学特征，以限制火山口形成阶段侧向岩浆侵入的空间范围。K-Ar年龄测定结果表明，所分析的大部分熔岩单元几乎与阿索破火山口形成的火山碎屑喷发（266 ~ 89 ka）同时喷发。此外，这些熔岩单元的岩石学、主微量元素组成和Sr同位素比值与破火山口形成的火山碎屑产物没有明显区别。火山口内外成分相似的岩浆同时期的活动可能表明，形成火山口的岩浆侧向侵入的发生，这些岩浆积聚在火山口系统下面的一个巨大的岩浆室中。我们的研究结果表明，在阿索火山形成火山口的岩浆中，总共有6.3%的岩浆从火山口中心沿断层迁移了20多公里。
We investigated the K–Ar ages and the petrological and geochemical features of lava units from lateral cones and lava distributed around the Aso caldera in central Kyushu, Japan, in order to constrain the spatial range of lateral magma intrusion during the caldera-forming stage. The results of the K–Ar age determination showed that most of the analyzed lava units erupted almost simultaneously with the Aso caldera-forming pyroclastic eruptions (266 to 89 ka). In addition, the petrography, major and trace element compositions, and Sr isotope ratios of these lava units are indistinguishable from the caldera-forming pyroclastic products. The contemporaneous activities of compositionally similar magmas inside and outside of the caldera presumably indicate the occurrence of a lateral intrusion of caldera-forming magma, which had accumulated in a huge magma chamber beneath the caldera system. Our results suggest that a total of 6.3 vol.% of caldera-forming magma in the Aso volcano migrated more than 20 km along the faults from the center of the caldera.