| 巴音戈壁盆地巴音戈壁组上段古盐度恢复及意义 |
| |
| 引用本文： | 高宏霞,刘晓东,刘平辉,孟平虹,向 龙,饶耕玮.巴音戈壁盆地巴音戈壁组上段古盐度恢复及意义[J].高校地质学报,2022,28(4):539-553. |
| |
| 作者姓名： | 高宏霞 刘晓东 刘平辉 孟平虹 向 龙 饶耕玮 |
| |
| 作者单位： | 1. 东华理工大学 地球科学学院，南昌 330013；
2. 核资源与环境国家重点实验室，南昌 330013；
3. 江西省核工业地质局263大队，吉安 343000 |
| |
| 摘 要： | 巴音戈壁盆地巴音戈壁组上段泥岩是中国高放废物深地质处置的目标研究层位之一，目前缺乏对该地层湖相泥岩粘土矿物组合特征及古盐度影响因素的相关认识。文章应用全岩的B含量、Sr/Ba比值、Rb/K比值及Na+K质量分数等方法和X衍射测试分析技术对巴音戈壁组上段古盐度进行综合判别。分析得出：（1）巴音戈壁组上段以半深湖—深湖沉积环境为主，发育有厚层深灰色泥岩，以半深湖至深湖相沉积为主；（2）研究区目的层岩性结构为泥粉质，该段泥岩伊利石、蒙脱石、伊蒙混层发育较好，绿泥石和高岭石极少；（3）选取样品的Sr/Ba、Rb/K、B/Ga、Na+K值同Couch公式恢复的古盐度变化趋向相似，其水体以半咸水、微咸为主；（4）随着深度增加，TZK-1井、TZK-2井的古盐度呈规律变化，具有升高—降低特点，与伊利石含量的变化一致，并且古盐度变化与古气候及氧化还原的相关研究在该岩性段位耦合。综上表明：目标区古盐度的研究不仅有利于湖盆古沉积环境的恢复，而且有助于揭示古盐度的变化特征对粘土矿物组合特征及演化的影响，为后期深入研究粘土矿物对核素吸附性能及核素在泥岩中的迁移情况提供一定依据。
|
| 关 键 词： | 古盐度 粘土矿物 Couch公式 巴音戈壁组 巴音戈壁盆地 |
Paleosalinity Characteristics and Geological Significance of the UpperBayingobi Formation in Yingejing Depression,Bayingebi Basin |
| |
| GAO Hongxia,LIU Xiaodong,LIU Pinghui,MENG Pinghong,XIANG Long,RAO Gengwei.Paleosalinity Characteristics and Geological Significance of the UpperBayingobi Formation in Yingejing Depression,Bayingebi Basin[J].Geological Journal of China Universities,2022,28(4):539-553. |
| |
| Authors: | GAO Hongxia LIU Xiaodong LIU Pinghui MENG Pinghong XIANG Long RAO Gengwei |
| |
| Institution: | 1. College of Earth Sciences, East China University of Technology, Nanchang 330013, China;
2. State Key Laboratory of Nuclear Resources and Environment, Nanchang 330013, China;
3. 263 Brigade of the Jiangxi Nuclear Industry Geological Bureau, Ji’an 343000, China; |
| |
| Abstract: | The mudstone of the upper Bayingobi formation in Bayingobi basin is one of the research targets for the deep geological disposal of high-level radioactive waste in China. At present, the combination characteristics of clay minerals and the factors affecting the paleosalinity of the mudstone are less studied. In this paper, the paleosalinity of the upper Bayingobi formation is comprehensively distinguished by the methods of B content, Sr/Ba ratio, Rb/K ratio, Na+K mass fraction and X-ray diffraction. The results are as follows：(1) The upper member of Bayingobi formation is dominated by semi deep lake-deep lake sedimentary environment with thick dark grey mudstone developed. And it mainly ranges from semi deep lake to deep lake facies. (2) The lithologic characteristic of the target formation in the study area is argillaceous and silty. Illite, montmorillonite and mixed layer of illite and montmorillonite are well developed while chlorite and kaolinite are relatively rare. (3) The values of Sr/BA, Rb/K, B/GA and Na+K of the selected samples are similar to the paleosalinity changes restored by Couch formula, and the water is mainly featured by brackish and saline water. (4)With increasing sample depths from TZK-1 and TZK-2 boreholes, the paleosalinity changes regularly, with the characteristics of increase-decrease, which is consistent with the change of illite content. The paleosalinity change is coupled with paleoclimate and redox research in this lithologic section. The results show that: The study of paleosalinity in the target formation is not only conducive to the restoration of paleosedimentary environment in the lake basin, but also helps to reveal the influence of paleosalinity variation on clay mineral assemblage characteristics and evolution. These results may provide a certain basis for the later in-depth study of clay mineral’ s nuclide adsorption performance and nuclide migration in mudstone. |
| |
| Keywords: | paleosalinity clay mineral Couch formula Bayinggebi Formation Bayinggebi Basin |
|
| 点击此处可从《高校地质学报》浏览原始摘要信息 |
| 点击此处可从《高校地质学报》下载免费的PDF全文 |
|
