Crustal anatexis and melt migrations in the Higo metamorphic terrane, west-central Kyushu, Kumamoto, Japan
Crustal anatexis and melt migrations in the Higo metamorphic terrane, west-central Kyushu, Kumamoto, Japan
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日本熊本九州中西部肥后变质地体的地壳深熔和熔融迁移
DOI：
10.1016/0024-4937(94)90026-4
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发表时间：
1994
期刊：
影响因子：
3.5
通讯作者：
Y. Osanai
中科院分区：
文献类型：
--
作者：
M. Obata;Y. Yoshimura;K. Nagakawa;S. Odawara;Y. Osanai
本文研究了日本九州一个高温、浅变质的火山岩中发育的深熔混合岩和浅色花岗岩。混合岩在这个岩石被分为变橄榄岩和diatexites和他们出现在石榴石-堇青石级和以上。浅色花岗岩的层、透镜体和豆荚（厚度为几厘米至6米）广泛分布在变质带中，并且最丰富，不是在最高级带，而是在不发育混合岩的中级带。混合岩浅色体通常贫正长石成分，而许多浅色花岗岩含有丰富的正长石。认为浅色花岗岩是从地壳深部生成并上升的过铝质熔体沉淀而成的结晶堆积体，变质混合岩带是深熔熔体的源区和通道区。由此可见，深熔熔体在该区域地壳中分离并上升了约5 km。另一方面，辉安山岩代表部分熔融的更高级阶段的固体熔融混合物，主要是黑云母分解。在HIGO的观测的影响进行了讨论，参考地壳深熔和花岗岩岩浆成因的演化方案。
This paper deals with the anatectic migmatites and leucogranites developed in a high-T, low-Pmetamorphic terrane, Kyushu, Japan. The migmatites in this terrane are divided into metatexites and diatexites and they occur at and above the garnet-cordierite grade. Layers, lenses and pods of leucogranite (a few centimeters up to 6 m in thickness) are wide-spread in the metamorphic terrane and are most abundant, not in the highest grade zone, but in intermediate grade zones, in which migmatites do not develop. The migmatite leucosomes are typically depleted in orthoclase component, while many leucogranites contain abundant orthoclase. It is suggested that the leucogranites are crystal cumulates precipitated from peraluminous melts, that had been generated and ascended from deeper levels in the crust and that the zone of metatectic migmatites represents both the source region and passage region for the anatectic melts. It is thus clear that the anatectic melts had segregated and ascended on the order of 5 km in the crust of this region. Diatexites on the other hand represent solid-melt mixtures at more advanced stages of partial melting, dominated by biotite breakdown. Implications of the observations made in the Higo terrane are discussed in reference to an evolutionary scheme for crustal anatexis and granite magma genesis.