Subvolcanic structure of the central dike swarm associated with the ring complexes in the Shitara district, central Japan
Subvolcanic structure of the central dike swarm associated with the ring complexes in the Shitara district, central Japan
复制标题
日本中部设乐地区与环状杂岩体相关的中央岩脉群的次火山结构
DOI：
10.1007/bf01275172
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发表时间：
1988
影响因子：
3.5
通讯作者：
A. Takada
中科院分区：
文献类型：
--
作者：
A. Takada
与日本中部中新世 Otoge 环杂岩和 Shitara 火成岩杂岩相关的中央岩脉群的次火山结构已被重建。中央岩墙群由几个排列整齐的岩浆库供给。在堤坝边缘观察到的流线向一个被视为岩浆库的区域汇聚，该区域位于当前海平面以下约 1-2 公里处。岩浆库的最小直径相当于中央岩脉群的宽度，估计约为3-4公里。推断的 Otoge 环杂岩岩浆库可能具有分区结构，如岩脉的流线和锥片的排列所示。长英质岩浆位于上部，距现海平面约1-2公里，基性岩浆位于下部，深度超过2公里。希塔拉火成岩杂岩的中心被解释为由其他几个浅层岩浆库组成。中心堤群平面视图中的分布模式是根据堤坝的频率（由垂直于堤群走向的方向上每公里的堤坝数量定义）和沿堤群的各个堤坝的不同属性的变化来概括的。它具有一个垂直于岩浆库上方岩脉群的对称平面。对总体理解岩浆岩形成的关键规律是：1.岩浆库上方存在低岩脉频率区域，岩浆库周围出现放射状岩脉模式。2.从岩浆库两侧看，高岩脉频率轴沿岩浆库群的中心区域对称延伸。3.长英质岩脉的数量、个体厚度和总厚度向岩浆库方向增加。4.基性岩脉的数量增加向岩浆库两侧延伸,而基性岩脉的个体厚度随着远离岩浆库而增大。
The Subvolcanic structure of the central dike swarm associated with the Miocene Otoge ring complex and the Shitara igneous complex, central Japan, has been reconstructed. The central dike swarm was supplied from several aligned magma reservoirs. Flow lineations observed at the margin of the dikes converge towards a region that is regarded as a magma reservoir about 1–2 km below present sea level. The minimum diameter of the magma reservoir corresponds to the width of the central dike swarm, estimated to be about 3–4 km. The inferred magma reservoir of the Otoge ring complex, may have a zoned structure, as suggested by the flow lineations of dikes and the arrangement of cone sheets. Felsic magma occupied the upper part, about 1–2 km below present sea level, and basic magma the lower part, deeper than 2 km. The centre of the Shitara igneous complex is interpreted to be composed of several other shallow magma reservoirs. The distribution pattern in plan view of the central dike swarm is summarized from the frequency of dikes (defined by the number of dikes per kilometre in the direction normal to the trend of the dike swarm) and the variations of the different properties of individual dikes along the dike swarm. It has a plane of symmetry normal to the dike swarm above the magma reservoir. The patterns critical to a general understanding of the dike formation are:1.A region of low dike frequency is present above the magma reservoir and a radial dike pattern occurs around the magma reservoir.2.From both sides of the magma reservoir, the axes of high dike frequency extend symmetrically along the central zone of the dike swarm.3.The number as well as the individual and total thickness of felsic dikes increases towards the magma reservoir.4.The number of basic dikes increases towards both sides of the magma reservoir, while the individual thicknesses of basic dikes increase with distance from the magma reservoir.