川东北下寒武统筇竹寺组稀土元素特征及其地质意义——以南江杨坝剖面为例

Characteristics of rare earth elements in Lower Cambrian Qiongzhusi Formation in northeastern Sichuan Basin and its geological implications: a case study of Yangba section, Nanjiang

曹婷婷 徐思煌 王约

CAO Tingting XU Sihuang Wang Yue

1. 中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126; 2. 中国石化油气成藏重点实验室, 江苏 无锡 214126; 3. 中国地质大学(武汉) 资源学院, 武汉 430074; 4. 贵州大学 资源与环境工程学院, 贵阳 550003

1. Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China; 2. Key Laboratory of Petroleum Accumulation Mechanisms, SINOPEC, Wuxi, Jiangsu 214126, China; 3. Resource Institute, China University of Geosciences, Wuhan, Hubei 430074, China; 4. College of Resource and Environmental Engineering, Guizhou University, Guiyang, Guizhou 550003, China

筇竹寺组是四川盆地重要的页岩气产层。为了揭示筇竹寺组优质烃源岩层段形成时期的物源区构造背景、物源特征及其沉积环境，选择四川盆地南江杨坝剖面出露较完整的下寒武统筇竹寺组系统采样，并对样品中稀土元素及微量元素进行分析。稀土元素分布模式及参数特征指示：整体上筇竹寺组物质来源较为一致，沉积物源区处于被动大陆边缘构造背景条件下，母岩以沉积岩和花岗岩混合为主，其中底部碳质页岩形成时期陆源碎屑中黏土矿物含量多。δCe与V/Cr参数指示：筇竹寺组底部形成于厌氧的水介质环境，中部—上部地层沉积时期属于贫氧—弱氧化的环境。

The Qiongzhusi Formation is an important shale gas production layer in the Sichuan Basin. A case study was made in the Yangba section of the northeastern Sichuan Basin. Samples were collected for rare earth and trace element analyses from the Lower Cambrian Qiongzhusi Formation in the study area so as to reveal the tectonic settings, provenance features and sedimentary environment when favorable source rocks were deposited. The distribution pattern and parameter characteristics of rare earth elements indicated that the Qiongzhusi Formation had a relatively consistent material source, mainly a passive continental margin. The parent rocks were mainly composed of sedimentary rocks and granites. When carbonaceous shale was deposited at the bottom of the Qiongzhusi Formation, the content of clay minerals increased in land sourced debris.The δCe and V/Cr parameters indicated that the bottom of the Qiongzhusi Formation was deposited in an anoxic reducing environment, while the middle and upper parts were deposited in a dysoxic-suboxic environment.

中国石油化工股份有限公司海相油气勘探前瞻性研究项目（G0800-06-ZS-319）和地质过程与矿产资源国家重点实验室科技部专项资助。

https://doi.org/10.11781/sysydz201805716