埃达克岩
指年龄小于25百万年的洋壳俯冲形成的一套岛弧岩浆岩系，此类岩石首次在阿拉斯加阿留申群岛的埃达克岛发现而确认。其特点：①是一套火山侵入岩组合，并非单一岩石类型；②岩相变化较大，主要由安山质英安质流纹质岩石组成；③其地球化学特征，以w(SiO2)≥56%、w（Al2O3）≥15%、w(MgO)＜3%为特点。Y和重稀土元素含量较岛弧安山岩英安岩流纹岩要低，而Sr较高；④埃达克岩多不与玄武岩或玄武安山岩共生；⑤87Sr/86Sr＜0.7040。是岛弧环境下高铝高锶而贫重稀土元素的一种特殊岩石组合。
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contributed at 2011-09-29
Classification(s)
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Earth System(in Chinese) Igneous petrology
Detailed Description
| English |
|---|
| Name | adakite |
| Chinese |
|---|
| Name | 埃达克岩 |
| Description | 指年龄小于25百万年的洋壳俯冲形成的一套岛弧岩浆岩系，此类岩石首次在阿拉斯加阿留申群岛的埃达克岛发现而确认。其特点：①是一套火山侵入岩组合，并非单一岩石类型；②岩相变化较大，主要由安山质英安质流纹质岩石组成；③其地球化学特征，以w(SiO2)≥56%、w（Al2O3）≥15%、w(MgO)＜3%为特点。Y和重稀土元素含量较岛弧安山岩英安岩流纹岩要低，而Sr较高；④埃达克岩多不与玄武岩或玄武安山岩共生；⑤87Sr/86Sr＜0.7040。是岛弧环境下高铝高锶而贫重稀土元素的一种特殊岩石组合。 |
How to Cite
NNU_Group (2011). 埃达克岩, Concept & Semantic, OpenGMS,
https://geomodeling.njnu.edu.cn/repository/concept/7912ad9e-bc45-4060-8ef0-1e36cba7eeff
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