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| 祁连山老君山砾岩的碎屑组成和源区大地构造背景 | |
| 引用本文： | 闫臻,肖文交,刘传周,袁超,王宗起,李继亮.祁连山老君山砾岩的碎屑组成和源区大地构造背景[J].地质通报,2006,25(1):83-98. |
| 作者姓名： | 闫臻 肖文交 刘传周 袁超 王宗起 李继亮 |
| 作者单位： | 1. 岩石圈演化国家重点实验室,中国科学院地质与地球物理研究所,北京,100029 2. 中国科学院广州地球化学研究所,广东,广州,410640 3. 中国地质科学院地质研究所,北京,100037 |
| 基金项目： | 科技部科研项目，中国科学院资助项目，中国科学院知识创新工程项目 |
| 摘 要： | 老君山砾岩是一套由砾岩和杂砂岩组成的陆相粗碎屑岩.砾岩由来自下伏基底的超镁铁岩、中-基性火山岩、硅质岩、花岗岩等碎屑组成.杂砂岩中岩屑含量大于70%,石英约10%,长石约15%.岩屑以中基性火山岩和花岗岩为主;硅质岩屑是主要的沉积岩屑.锆石、磷灰石、磁铁矿是杂砂岩中最为丰富的重矿物,同时还有铬铁矿、石榴子石、电气石、金红石、黄铁矿.这些事实说明,老君山砾岩的源区曾出露有超镁铁岩、中基性火山岩、变质岩等类型的岩石.砂岩碎屑模式和粉砂岩、泥岩的地球化学成分均表明,老君山砾岩源区为大陆边缘弧和大洋岛弧,形成于活动大陆边缘与岛弧相关的沉积盆地中. |
| 关 键 词： | 老君山砾岩 碎屑组成 重矿物 源区背景 与岛弧有关的盆地 祁连山 |
| 文章编号： | 1671-2552（2006）01-02-0083-16 |
| 收稿时间： | 2005-04-22 |
| 修稿时间： | 2005-10-25 |
Detrital composition of the Laojunshan conglomerate in the Qilian Mountains, Northwest China and tectonic settings of its source regions |
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| YAN Zhen,XIAO Wen-jiao,LIU Chuan-zhou,YUAN Chao,WANG Zong-qi,LI Ji-liang.Detrital composition of the Laojunshan conglomerate in the Qilian Mountains, Northwest China and tectonic settings of its source regions[J].Geologcal Bulletin OF China,2006,25(1):83-98. | |
| Authors: | YAN Zhen XIAO Wen-jiao LIU Chuan-zhou YUAN Chao WANG Zong-qi LI Ji-liang |
| Institution: | 1. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, CAS, Beijing 100029,China; 2. Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 410640,Guangdong,China; 3. Institute of Geology, Chinese Academy of Geo |
| Abstract: | The Laojunshan conglomerate is a suite of continental coarse clastic rocks consisting of conglomerate and graywacke. Conglomerate is composed of fragments of ultramafic rocks, intermediate-basic volcanic rocks, chert and granite derived from the underlying basement. Graywacke contains more than 70% lithic fragments, of which quartz constitutes -10 % and feldspar -15%. Intermediate-basic volcanic rocks and granite are the dominant lithic fragments. Chert fragments are dominant sedimentary fragments of greywacke. Zircon, apatite and magnetite are the most abundant heavy minerals in graywacke. In addition, chromite, garnet, tourmaline, ruffle and pyrite also occur in sandstone. This demonstrates that ultramafic, intermediate-basic and metamorphic rocks may have outcropped in the source regions of the Laojunshan conglomerate. The sandstone detrital model and geochemical compositions of siltstone and mudstone of the Laojunshan conglomerate suggest that their source regions were the continental-margin arc and oceanic island arc. These indicate that the Laojunshan conglomerate formed in active continental margins and an arc-related basin. |
| Keywords: | Laojunshan conglomerate detrital composition heavy mineral source region setting are-related basin Qilian Mourtains |
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