| 云南思茅盆地江城上白垩统勐野井组稀土微量元素特征及地质意义 |
| |
| 引用本文： | 石海岩,马海州,苗卫良,李永寿,张西营.云南思茅盆地江城上白垩统勐野井组稀土微量元素特征及地质意义[J].地球化学,2014(4):415-427. |
| |
| 作者姓名： | 石海岩 马海州 苗卫良 李永寿 张西营 |
| |
| 作者单位： | 中国科学院青海盐湖研究所盐湖资源与化学重点实验室;中国科学院大学; |
| |
| 基金项目： | 国家重点基础研究发展计划(2011CB403004);中国科学院知识创新工程重要方向项目(KZCX2-YW-344) |
| |
| 摘 要： | 沉积盆地中碎屑岩的地球化学成分主要受物源区控制，因此，通过分析碎屑岩的化学成分可以揭示盆地沉积岩的源区构造背景和物源属性。思茅盆地上白垩统勐野井组（K2me）细碎屑岩的稀土元素组成分析结果表明，研究区沉积物具有轻稀土元素富集，较平坦的重稀土元素分布模式，以及中等程度 Eu 负异常的总体特征。根据样品的（Hf-La/Th、La/Sc-Co/Th和REE-La/Yb）图解，特征性微量元素比值（La/Sc、Sc/Th、Cr/Th 和 Co/Th），并结合岩矿薄片分析，认为勐野井组细碎屑岩具有典型的上陆壳特征，源区母岩以长英质岩石为主。微量元素 Cr/Co 结合岩相古地理的分析显示勐野井组细碎屑沉积物应属于近源沉积。通过与不同构造背景下杂砂岩的稀土元素特征对比及主元素（K2O/Na2O-SiO2/Al2O3和SiO2-K2O/Na2O）判别图解，勐野井组细碎屑岩源区构造背景应属被动大陆边缘环境，这与思茅盆地所处的三江造山带构造背景相符。
|
| 关 键 词： | 上白垩统 勐野井组 地球化学特征 物源属性 构造背景 思茅盆地 |
Characteristics and geological significances of rare earth and trace elements from Upper Cretaceous Mengyejing Formation of Simao Basin in Jiangcheng County,Yunnan Province |
| |
| Institution: | SHI Hai-yan,MA Hai-zhou,MIAO Wei-liang,LI Yong-shou,ZHANG Xi-ying(1. Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China) |
| |
| Abstract: | The geochemical compositions of clastic rocks in sedimentary basin are mainly controlled by provenance. Therefore, tectonic setting and provenance properties of sedimentary basin could be revealed by geochemical characteristics of clastic rocks. In this study, trace elements （including rare earth elements） of fine-grained clastic rocks have been analyzed to investigate the provenance in Mengyejing Formation （K2me） of Simao Basin in Late Cretaceous. The results show relative enrichments in light REEs, with flat HREE patterns and moderate Eu anomalies. Using Hf-La/Th, La/Sc-Co/Th and REE-La/Yb diagram, trace elements ratios （La/Sc, Sc/Th, Cr/Th and Co/Th）, and combines with microscopic identification, the geochemical characteristics of sediments are the same as weathered upper continental curst and the sources of sediments are mainly from continental crust with felsic rocks. In addition, the sediment transport distance of clastic rocks in Mengyejing Formation were analyzed by the ratio of Cr/Co and lithofacies paleogeographical study, and the results show that the clastic rocks is featured by proximity of its origin deposition. Compared to REE characteristics of graywacks in different tectonic settings, and Using （K2O/Na2O-SiO2/Al2O3 and SiO2-K2O/Na2O） diagram we proposed that the tectonic setting of source area of clastic rocks in Mengyejing Formation belongs to the passive continental margin, and the result is consistent with the tectonic setting of the Simao Basin which located in the Sanjiang orogenic belt. |
| |
| Keywords: | Upper Cretaceous Mengyejing Formation geochemical characteristics provenance properties tectonic setting Simao Basin |
| 本文献已被 CNKI 维普 等数据库收录！ |
|
