| 黔东震旦-寒武系转换期碎屑锆石年龄及其地质意义 |
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| 引用本文： | 杨恩林,吕新彪,石 平,吴 波,刘 文,狄永宁.黔东震旦-寒武系转换期碎屑锆石年龄及其地质意义[J].地球科学,2014,39(4):387-398. |
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| 作者姓名： | 杨恩林 吕新彪 石 平 吴 波 刘 文 狄永宁 |
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| 作者单位： | 1.中国地质大学资源学院，湖北武汉 430074 |
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| 基金项目： | “十二五”国家科技支撑计划项目05子课题(No.2011BAB06B04-05);贵州地矿局地质科研项目(No.200901) |
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| 摘 要： | 通过对注溪地层剖面岩性、含矿性及接触关系进行详细考察，及对其黑色岩系中长石岩屑砂岩进行碎屑锆石LA-ICP-MS U-Pb测年，获得84组有效年龄，其中864~742 Ma年龄最集中，表明新元古代黔东地区存在大规模的岩浆活动.江南造山带为黔东早寒武世黑色岩系的主要沉积物源区，而钒等成矿元素源于基性-超基性侵入岩体.雪峰运动导致这些含矿岩体剥顶，大量金属元素注入海洋.海侵海底缺氧，富含这些成矿元素藻类死亡，钒等金属元素随同有机质进入沉积物中，在利于其沉淀富集的留茶坡和九门冲组地层成矿.536 Ma为留茶坡组最后接受沉积时限和九门冲组最大沉积年龄，震旦与寒武系界线位于留茶坡组中上部硅质岩中，清水江组地层岩性的变形、变质和角度不整合于上覆、下伏地层的现象为雪峰运动地质效应.
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| 关 键 词： | 地层学 碎屑锆石 沉积 地质年代学 注溪剖面 |
| 收稿时间： | 2013-07-19 |
Detrital Zircon Age of Stratigraphic Sinian-Cambrian in East Guizhou and Its Geological Significance |
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| Abstract: | Lithology, ore-bearing potential and contact relation in Zhuxi stratigraphic section are studied in detail. 84 groups of effective ages concentrated in 864-742 Ma are obtained from U-Pb dating of detrital zircon by LA-ICP-MS in feldspar lithic sandstone in the black shales, which indicates the presence of large-scale magmatic activity of the East Guizhou at the Neoproterozoic. All zircon U-Pb ages indicate that sediments within Lower Cambrian black shales in East Guizhou are mainly from the Jiangnan orogen. Metal elements such as vanadium are derived from the basic-ultrabasic rocks. The Xuefeng movement peeled the top of ore-bearing rock off the basic-ultrabasic rocks, pouring a great amount of metal into the ocean. The anoxic submarine caused the death of algae whose bodies were rich of metallogenic elements, which introduced vanadium into the sediments along with the organic matter. The mineralization occurred in the Liuchapo and Jiumenchong formations that were favorable to sedimentation of metals. 536 Ma is the final depositional time of the Jiumenchong Formation, and maximum depositional age of the Liuchapo Formation. The boundary between Sinian and Cambrian is located in the upper siliceous rocks of the Liuchapo Formation. Lithology deformation, metamorphism, and unconformity with other strata of the Qingshuijiang Formation are the geological responses of the Xuefeng movement. |
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