| 云南乌东德水电站施期料场中元古代热液白云岩研究 |
| |
| 引用本文： | 于永顺,焦良轩,欧阳光,胡进武,刘冲平,张熊,宛良朋,李果,佘振兵,王团乐.云南乌东德水电站施期料场中元古代热液白云岩研究[J].地质科技通报,2021,40(1):36-48. |
| |
| 作者姓名： | 于永顺 焦良轩 欧阳光 胡进武 刘冲平 张熊 宛良朋 李果 佘振兵 王团乐 |
| |
| 作者单位： | 中国地质大学（武汉）地球科学学院;中国三峡建设管理有限公司乌东德工程建设部;长江三峡勘测研究院有限公司 |
| |
| 基金项目： | 长江三峡勘测研究院有限公司(武汉)项目"云南乌东德水电站中元古代碳酸盐岩成因及其工程地质意义"2017016018"金沙江乌东德水电站施期料场灰岩沿结构面浸染黑色物质与灰岩顶部白云岩化形成机理及对混凝土性能影响和措施研究项目"WDD-0523 |
| |
| 摘 要： | 云南禄劝乌东德水电站是我国第三座超千万千瓦级水电站,其建设所采用的混凝土人工骨料来源于坝址下游施期料场的中元古代落雪组灰岩。在骨料勘察和实际开采过程中,发现灰岩与白云岩在同一层位产出,其岩性变化界线切割岩层面,该类现象为工程地质研究中所罕见,引起了高度关注。以施期料场灰岩-白云岩过渡带和骨料开采残留的一处白云岩凸起岩块为重点研究对象,开展了野外地质调查、室内岩相学、微区矿物形貌和成分、碳氧同位素以及流体包裹体分析,深入探讨了研究区碳酸盐岩成岩演化和岩相转变过程与机理,提出了新的白云岩化成因模式。结果表明:①矿物形貌和空间分布特征指示与灰岩过渡的白云岩为早期灰岩经过后期白云岩化形成;②白云岩中发育的斑马纹构造、鞍状白云石及其伴生的硫化物和碳质物等,指示其经历了热液白云岩化过程。鞍状白云石中流体包裹体的均一温度(183~215℃)显著高于围岩方解石中流体包裹体均一温度(102~152℃);③白云岩普遍具有较轻的O同位素值(δ^18O=-13.3‰~-7.8‰),而其中鞍状白云石的δ^18O最低(-13.3‰),表明它们可能为热液流体直接沉淀的产物,而其他白云岩由于受热液流体影响程度较低而具有较低的包裹体均一温度和较高的δ^18O值;④乌东德地区近直立的岩层产状和断裂可能为热液流体运移提供了通道,而其上覆的近水平震旦系灯影组厚层白云岩则起到了封堵作用,使热液流体在不整合面之下与灰岩发生长时间反应;热液流体的运移方向决定了最终的热液白云岩的分布。
|
| 关 键 词： | 施期料场 热液白云岩化 鞍状白云石 流体包裹体 |
| 收稿时间： | 2020-01-08 |
Hydrothermal dolostones in the Shiqi quarry of Wudongde Hydropower Station,Yunnan |
| |
| Yu Yongshun,Jiao Liangxuan,Ouyang Guang,Hu Jinwu,Liu Chongping,Zhang Xiong,Wan Liangpeng,Li Guo,She Zhenbing,Wang Tuanle.Hydrothermal dolostones in the Shiqi quarry of Wudongde Hydropower Station,Yunnan[J].Bulletin of Geological Science and Technology,2021,40(1):36-48. |
| |
| Authors: | Yu Yongshun Jiao Liangxuan Ouyang Guang Hu Jinwu Liu Chongping Zhang Xiong Wan Liangpeng Li Guo She Zhenbing Wang Tuanle |
| |
| Affiliation: | (School of Earth Sciences,China University of Geosciences(Wuhan),Wuhan 430074,China;Wudongde Engineering and Construction Department,China Three Gorges Corporation,Luquan Yunnan 651500,China;Three Gorges Geotechnical Consultants CO.,LTD,Wuhan 430074,China) |
| |
| Abstract: | The Wudongde Hydropower Station in Yunan is the third hydropower station in China with a capacity of over 10 million kilowatts.The artificial aggregate used in its construction is derived from the limestone of the Mesoproterozoic Luoxue Formation of downstream the dam site.However, both limestone and dolostone are found in the aggregate survey and mining yard, meanwhile the lithological boundary between cross cuts the stratum.This paper focuses on the limestone-dolomite transition zone and a dolomite bulge remaining in the aggregate mining yard.Detailed geological survey, petrological work and geochemical analysis have been conducted on the samples of the research area.The results show that: ①Morphological features and spatial relationships of the carbonate minerals suggest that the dolostones are formed by dolomitization of limestone precursors. ②The development of zebra structure, saddle dolomite and associated sulfides and carbonaceous material is consistent with hydrothermal dolomitization. ③Fluid inclusions in the saddle dolomite yield homogenization temperatures between 183 and 215 ℃, which are significantly higher than those of fluid inclusions in the surrounding calcite(102-152 ℃).The dolostones are generally depleted in 18O(δ18O=-13.3‰ to -7.8‰), with the saddle dolomites have the lowest δ18O value(-13.3‰), which is consistent with direct precipitation of dolomite from hydrothermal fluids.The other dolomites, which show lower homogenization temperatures and higher δ18O, are probably related to less influence by the hydrothermal fluids. ④The near-vertical strata and the presence of fractures in the Shiqi area might have provided channels for the migration of hydrothermal fluids, while the overlying dolostones of Sinian Dengying Formation probably have acted as a cap layer, allowing prolonged reactions between the hydrothermal fluids and surrounding limestones.The migration direction of the hydrothermal fluids determines the distribution of the hydrothermal dolostones. |
| |
| Keywords: | Shiqi quarry hydrothermal dolomitization saddle dolomite fluid inclusions |
| 本文献已被 维普 等数据库收录！ |
| 点击此处可从《地质科技通报》浏览原始摘要信息 |
|
点击此处可从《地质科技通报》下载全文 |
|
