| 大兴安岭南段早二叠世两类火山岩岩石地球化学特征及其构造意义 |
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| 引用本文： | 吕志成,郝立波,段国正,李殿超,潘军.大兴安岭南段早二叠世两类火山岩岩石地球化学特征及其构造意义[J].地球化学,2002,31(4):338-346. |
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| 作者姓名： | 吕志成 郝立波 段国正 李殿超 潘军 |
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| 作者单位： | 1. 中国科学院地球化学研究所矿床地球化学开放实验室,贵州贵阳,550002;吉林大学,吉林长春,130026
2. 吉林大学,吉林长春,130026 |
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| 基金项目： | 教育部博士点基金(97018701)，国家攀登计划预选项目(95-预-39)，中国科学院百人计划项目资助 |
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| 摘 要： | 大兴安岭南段二叠系大石寨组发育两套火山岩，即林西地区拉斑玄武岩系列的细碧－角斑岩类和大石寨地区钙碱性岩石系列玄武岩和玄武安山岩类。细碧岩的主元素以富铁为特征，成分类似于N－MORB，微量元素表现为岛弧拉斑玄武岩的地球化学特征。细碧岩类形成于大石寨裂陷槽强烈拉张的中心位置，是地幔源区较高程度部分熔融的产生。大石寨地区玄武岩和玄武安山岩类的化学成分表现为大陆缘弧火山岩的地球化学特点，形成于大石寨裂隙槽拉张中心以外的环境，是地幔物质较低程度部分熔融和地壳物质严重混染的产物。大石寨裂隙槽中火山岩的这种独特的成分和组合特点可能反映了裂隙槽的形成是一个快速而短暂的强烈拉张过程。
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| 关 键 词： | 早二叠世 细碧岩 玄武岩 玄武安山岩 岩石地球化学特征 构造意义 大兴安岭 |
| 文章编号： | 0379-1726(2002)04-0338-09 |
| 修稿时间： | 2001年5月25日 |
Lithogeochemical characteristics and tectonic implications of two series of volcanic rocks from Early Permian Dashizhai Formation in the south section of Da Hinggan Mountains |
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| Abstract: | There occur two series of volcanic rocks of Lower Permian Dashizhai Formation in the south section of Da Hinggan Mountains. One is tholeiitic series volcanic rocks at Linxi area composed of spilites in the southwest Dashizhai fault trough basin, and the other is calc alkaline series volcanic rocks at Dashizhai area composed of basalt and basaltic andesite in the northeast Dashizhai fault trough basin. The lithogeochemical characteristics of the Linxi spilites are similar to those of the N MORB. The results of the regional geological studies indicate that the Linxi spilites were formed in the central part of the rifting Dashizhai fault trough basin, and they are the product of partial melting of the mantle in higher degree. The lithogeochemical characteristics of the Dashizhai basalts and basaltic andesites are similar to those of the continent arc margin basalts. And they were developed in other parts of the Dashizhai fault trough basin, and they are the products of partial melting of mantle in low degree and contaminated by upper crust severely. The composition and assemblage of volcanic rocks in the Dashizhai fault trough basin may indicate that the Dashizhai fault trough basin developed rapidly and shortly. |
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| Keywords: | spilite basalt basaltic andesite lithogeochemical characteristics tectonic implication Da Hinggan Mountains |
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