| 黔中乌当盆地阶地沉积特征及其对盆地演化的指示 |
| |
| 引用本文： | 蒋玺,陈文奇,宁凡,郑军,罗维均,周涌.黔中乌当盆地阶地沉积特征及其对盆地演化的指示[J].地理研究,2020,39(6):1242-1254. |
| |
| 作者姓名： | 蒋玺 陈文奇 宁凡 郑军 罗维均 周涌 |
| |
| 作者单位： | 1. 贵州大学资源与环境工程学院,贵阳 550025;2. 中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳 550081 |
| |
| 基金项目： | 贵州省科技支撑计划项目(黔科合支撑[2019]2852号);国家自然科学基金项目(41673121);贵州大学教学研究重点项目(JGZD201508) |
| |
| 摘 要： | 黔中乌当盆地是贵州省山间盆地的典型代表,四级河流阶地清晰地记录了新构造运动中区域地壳抬升和盆地演化。通过阶地沉积物砾组统计、粒度分析、光释光（OSL）测年,探讨盆地的发育和演化。结果显示,阶地砾石排列指示盆地水系古流向与现代河流基本一致,砾石磨圆度变化大,分选较差,岩性继承了区域地层。砾石组合特征反映了构造抬升期盆地内强烈的冲刷剥蚀。漫滩沉积物粒度表明盆地在稳定阶段河流水动力整体呈增大趋势。T4和T3发育阶段区域以冲刷剥蚀为主并塑造了盆地雏形。T2阶地沉积特征及测年结果（177.4 ka~87.6 ka）表明中更新世末期持续数万年的沉积夷平作用使盆地基本成型。T1阶地形成时代约25ka,指示了黔中地区最近一次构造抬升和盆地的最终定型。
|
| 关 键 词： | 乌当盆地 阶地 砾组统计 粒度分析 OSL测年 |
| 收稿时间： | 2019-06-24 |
| 修稿时间： | 2019-09-17 |
Sediment characteristics of terraces in Wudang Basin and their implications on basin evolution |
| |
| JIANG Xi,CHEN Wenqi,NING Fan,ZHENG Jun,LOU Weijun,ZHOU Yong.Sediment characteristics of terraces in Wudang Basin and their implications on basin evolution[J].Geographical Research,2020,39(6):1242-1254. |
| |
| Authors: | JIANG Xi CHEN Wenqi NING Fan ZHENG Jun LOU Weijun ZHOU Yong |
| |
| Institution: | 1. College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China;2. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550081, China |
| |
| Abstract: | Studying river terrace is an important way to explore regional evolution of hydrology, paleoclimate and geomorphology. There is few reports about terraces of Guizhou because intense weathering results in poor profile preservation in this area. In Wudang Basin, a typical intermountain basin located in central Guizhou, Neotectonic movement resulted in a well-preserved sequence of four terraces, which indicates the regional crustal uplift and basin evolution clearly. In this article, measurements on gravel fabric and grain size of sediments are used to analyze the sedimentary environment of terraces. And then, combined with optical luminescence (OSL) dating, the discussion is focused on evolution age and process of Wudang Basin. The results show that in the study area, the gravels are poorly sorted and varying roundness but well orientated with river flows. The fact that lithology of gravels possess distinct inheritance indicates that they come from the surrounding stratum. Based on the gravel fabric analysis, it is concluded that the basin experienced an intense erosion during tectonic uplift. Grain size measurements on floodplain sediments present that dynamics of the rivers have an increasing tendency, which indicates regional climatic changes during a relatively tectonic stable stage. In stages of T4 and T3, there was erosion and denudation in Wudang Basin, which formed the embryo of the modern geomorphology. OSL dating shows that the age of T2 terrace is from 177.4 ka to 87.6 ka, which is consistent with the last interglacial in the sequence of Chinese glaciations and MIS5 (125 to 75 ka). So it is held that in stage of T2, warm and humid climate was important for terrace deposit up to a 10-m thickness. Based on sediment characteristics and time series, it is believed that at the late stage of Middle Pleistocene, there was a sedimentary leveling lasting for tens of thousands of years before Wudang Basin basically formed. The age of T1 terrace is about 25 ka, indicating the last tectonic uplift of Guizhou and the final shaping of Wudang Basin. |
| |
| Keywords: | Wudang Basin terrace gravel fabric analysis grain size analysis OSL dating |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《地理研究》浏览原始摘要信息 |
| 点击此处可从《地理研究》下载免费的PDF全文 |
|
