浅变质泥页岩的基本特征及环境分析——以阿尔金红柳沟Ⅰ号剖面新元古界冰沟南组为例

Characteristics and environment indication of mud shale undergone low temperature metamorphism: a case study of Neoproterozoic Binggounan Formation, Hongliugou Ⅰ section, Altyn Tagh fault

钱一雄 储呈林 李曰俊 王毅 张仲培 杨鑫 李王鹏 马红强 陈跃 邵志兵 庄新兵

QIAN Yixiong CHU Chenglin LI Yuejun WANG Yi ZHANG Zhongpei YANG Xin LI Wangpeng MA Hongqiang CHEN Yue SHAO Zhibing ZHUANG Xinbing

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 中国科学院 地质与地球物理研究所, 北京 100029 中国石化 石油勘探开发研究院, 北京 100083

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China SINOPEC Petroleum Exploration & Production Research Institute, Beijing 100083, China

阿尔金西北缘红柳沟Ⅰ号剖面的新元古界冰沟南组泥页岩发育于被动大陆边缘盆地，是一套与硅质岩互层、浅变质、厚近60 m、曾具有生烃能力的陆棚沉积。通过实测地层剖面、矿物学及地球化学研究，探讨了其构造属性、物源区、风化作用及沉积环境。研究表明：该泥页岩主要属于富硅黏土岩、富泥硅质页岩，次为泥—硅混合页岩；与澳大利亚后太古宙页岩（PAAS）相比，其Si、Mg、K、P、Sc、Y、Hf、Th、Sc等含量相似，Ti、Mn、Fe、Ta、δEun、δCen和ΣREE等值相对较高，Al、Ca、Na，Nb和Zr等值较低。冰沟南组泥页岩由再循环沉积碎屑、中基性及中酸性侵入岩作为第一沉积物的来源，与大陆上地壳硅铝质和一般页岩组成接近；物源区为温暖、湿润条件下中等化学风化条件；自下而上可划分出3个厌氧—缺氧为主、偶夹有氧化的沉积旋回；下部叠加了热流体改造。统计表明，40%左右黏土含量的泥页岩段富集主要微量元素（稀土）及有机质，是陆棚中的贫氧—缺氧、生产力较高、生烃潜力最好层段。

The Neoproterozoic Binggounan Formation mud shale in the Hongliugou Ⅰ section on the northwestern margin of the Altyn Tagh fault was deposited in a passive continental margin. They are shelf sediments about 60 m thick, interbedded with siliceous rocks, undergone a low temperature thermodynamic metamorphism, and had hydrocarbon generation potential. The tectonic background, provenance, weathering and sedimentary environment of the mud shale were discussed with regard to stratigraphic sections, mineralogy and geochemical analyses. The mud shale was mainly composed of silica-rich clay rock and mud-rich siliceous shale, followed by mud-silica mixed shale. They have simila-rities in Si, Mg, K, P, Sc, Y, Hf, Th Sc contents compared with the Post Archaean Australian shale (PAAS). The Ti, Mn, Fe, Ta contents and δEun, δCen, ΣREE values are higher, while the Al, Ca, Na, Nb and Zr contents are lower. The primitive sediment sources of the Binggounan mud shale were recycled sedimentary clasts, intermediate mafic and acid intrusive rocks, similar to a normal shale and arenites argillites and ensialic of continental upper crust in composition. The shale has undergone moderate chemical weathering in warm and humid conditions. The formation was divided into three sedimentary cycles from bottom to top, mainly anaerobic and anoxic, and occasionally oxidized. Hydrothermal alteration also occured in the lower section. The mud shale with a clay content of about 40% is rich in trace elements (REE) and organic matter, which was deposited in a suboxic to anoxic section on the shelf, showing a high productivity and hydrocarbon-generation potential.

国家重点研发计划“中新元古界微生物碳酸盐岩沉积环境与成储机制” 2017YFC0603103;中国石化科技部项目“塔里木盆地新元古界—寒武系沉积特征与源储条件” P17046-4

https://doi.org/10.11781/sysydz202102193