| 准噶尔盆地陆东—五彩湾地区石炭系中、基性火山岩地球化学及其形成环境 |
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| 引用本文： | 赵霞,贾承造,张光亚,卫延召,赖绍聪,方向,张丽君.准噶尔盆地陆东—五彩湾地区石炭系中、基性火山岩地球化学及其形成环境[J].地学前缘,2008,15(2):272-279. |
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| 作者姓名： | 赵霞 贾承造 张光亚 卫延召 赖绍聪 方向 张丽君 |
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| 作者单位： | 1. 中国石油勘探开发研究院,北京,100083
2. 西北大学,地质学系,陕西,西安,710069 |
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| 基金项目： | 中国石油股份公司科技研发项目 |
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| 摘 要： | 准噶尔盆地是发育在前寒武纪结晶基底与古生代褶皱基底双重基底之上的中、新生代沉积盆地。盆地东北缘陆东—五彩湾地区发育大量的石炭系中、基性火山岩,主要由玄武岩、熔结玄武岩、气孔-杏仁玄武岩与辉绿岩组成。其中、基性火山岩具有低钾高钛、高∑REE的特征,球粒陨石标准化的REE配分曲线表现轻稀土富集,轻、重稀土分异的谱线特征,微量元素具有大离子亲石元素富集,Ta、Nb亏损的现象,可能与板内拉张环境下地壳混染或地幔源区有富Ta、Nb的残留体有关,微量元素环境判别图解中大部分样品点落入板内玄武岩区域,少量漂向岛弧火山岩区,表现出主体为板内构造环境;高场强元素Th/Nb、Nb/Zr比值进一步表现出火山岩具有板内火山岩的特征。综合区域地质特征及前人的研究结果,认为准噶尔盆地陆东—五彩湾地区中、基性火山岩应属造山期后伸展背景下的火山作用产物,但岩浆源区可能受到古洋壳板片俯冲作用的影响。
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| 关 键 词： | 准噶尔盆地 陆东—五彩湾地区 石炭系 基性火山岩 地球化学 构造环境 |
| 文章编号： | 1005-2321(2008)02-0272-08 |
| 修稿时间： | 2007年12月10 |
Geochemistry and tectonic settings of Carboniferous intermediate-basic volcanic rocks in Ludong-Wucaiwan, Junggar basin |
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| Zhao Xia,Jia Chengzao,Zhang Guangya,Wei Yanzhao,Lai Shaocong,Fang Xiang,Zhang Lijun.Geochemistry and tectonic settings of Carboniferous intermediate-basic volcanic rocks in Ludong-Wucaiwan, Junggar basin[J].Earth Science Frontiers,2008,15(2):272-279. |
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| Authors: | Zhao Xia Jia Chengzao Zhang Guangya Wei Yanzhao Lai Shaocong Fang Xiang Zhang Lijun |
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| Abstract: | The basement of the Junggar basin is a part of Kazakhstan plate,and is interspersed in the Tarim plate and the Siberia plate.The Ludong-Wucaiwan area,located on the northeast of the basin,has a lot of Carboniferous neutral-basic volcanic rocks,which is the key to the research on the Carboniferous tectonic setting of the Junggar basin.The volcanic rocks are mainly composed of basalt,sintered basalt,andesite-basalt,amygdaloidal basalt and diabase.The geochemistry shows the characteristics of low K,higher Ti and high ∑REE.The trace element compositions of different volcanic rocks are all rich in LREE without obvious Eu anomaly,LILE are rich in the basalt,Nb and Ta relative to La are depleted strongly.This type of volcanic rocks shows not only the signature of within-plate setting,but also that of a subduction zone.The geochemical characteristics are similar to some characteristics of "lagged arc volcanic rocks".Combining with the regional geological data and previous research findings,we conclude that the Carboniferous basic volcanic rocks of the study area were generated in an extensional setting of the late stage of orogenesis,but the magma source may have been influenced by the earlier oceanic plate subduction. |
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| Keywords: | Junggar basin Ludong-Wucaiwan Carboniferous basic volcanic rocks geochemistry tectonic setting |
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