| 岩浆不混溶对岩石成分和结构的控制———川西乡城地区玻镁安山岩成岩特征探讨 |
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| 引用本文： | 谭劲,赵珊茸,莫宣学,邓晋福.岩浆不混溶对岩石成分和结构的控制———川西乡城地区玻镁安山岩成岩特征探讨[J].地球科学,1997(2). |
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| 作者姓名： | 谭劲 赵珊茸 莫宣学 邓晋福 |
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| 作者单位： | 地球科学学院，地质矿产系 |
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| 摘 要： | 川西乡城地区的球颗状玻镁安山岩是一种玻璃质、含辉石斑晶、具淬火结构的中性熔岩．它相对富硅富镁、贫钛贫磷，产于三叠纪川西义敦岛弧早期火山活动阶段．外观最醒目特征是具有球颗构造，从化学成分和岩浆性质分析，球颗构造是成岩过程中岩浆不混溶的直接产物．不混溶对岩石成分和结构起着控制作用；岩石中球颗相富硅碱，以玻璃质结构为主，而基质相富铁镁，以微晶结构为主．成岩时化学成分随岩浆不混溶发生相对分离，该岩浆属于一种低程度不混溶．结构差异是两相中矿物结晶能力不同的结果
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| 关 键 词： | 岩浆不混溶，玻镁安山岩，球颗构造，川西乡城地区 |
MAGMA IMMISCIBLE CONTROLING ROCK COMPOSITION AND TEXTURE:DISCUSSION ON BONINITE IN XIANGCHENG AREA, WESTERN SICHUAN PROVINCE |
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| Tan Jin.MAGMA IMMISCIBLE CONTROLING ROCK COMPOSITION AND TEXTURE:DISCUSSION ON BONINITE IN XIANGCHENG AREA, WESTERN SICHUAN PROVINCE[J].Earth Science-Journal of China University of Geosciences,1997(2). |
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| Authors: | Tan Jin |
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| Abstract: | The spherolitic boninites in Xiangcheng area, Western Sichuan Province, are glassy medium lava which possesses pyroxene phenocryst and quenched texture. Boninites are relatively high in Mg and Si, but low in Ti and P. They occur in early stage of arc volcanism in Late Triassic of this area. Their most distinguishing outlook is the spherolitic structure. Analysis of their composition and magmatic properties shows that the spherolitic structure was the direct product of magma immiscible, which controled the rock composition and texture. The spherolitic phase enriched Si and Alk, mainly is glassy texture. The matrix phase enriched Mg and Fe, mainly is microcrystal texture. The chemical composition has been relatively separated by the magma immiscible in low degree in the period of rock forming. Differences of texture between two phases are the differences of mineral crystallization. |
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| Keywords: | magma immiscible boninite spherolitic structure Xiangcheng area in Sichuan Province |
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