石油实验地质2019，Vol.41Issue(1)：121-126,6.DOI:10.11781/sysydz201901121
陕西铜川地区延长组长7油页岩无机地球化学特征及古环境恢复
Inorganic geochemical characteristics and paleoenvironment of Chang 7 oil shale in Yanchang Formation, Tongchuan area, Shaanxi Province
摘要
Abstract
The geochemistry of shale core samples from the 7 th member (Chang 7) of Triassic Yanchang Formation were analyzed in order to study the characteristics of sedimentary palaeoenvironment such as salinity, redox condition, depth, hydrothermal activity and palaeoclimate when the Chang 7 member was deposited in the Tongchuan area, Shaanxi Province. The content of Sr is 198.28×10-6, Sr/Ba is 0.39, V/Ni is 4.50, the equivalent boron content by the Walker method in most samples is less than 200×10-6, and the lowest value is about 40×10-6. Based on the above characteristics, it can be concluded that the Chang 7 oil shale was deposited in a brackish fresh water and anaerobic environment. The quantitative determination of cobalt indicated that the sedimentary environment was a lake with a maximum water depth of 40-70 m. The average Sr/Cu ratio is 4.28, which means that the paleoclimate was warm-wet and semi-humid. P, Cu, Co, Ni, V and Rb were enriched. The total REE was low, and the HREE was enriched. Ce showed a negative anomaly. Most of the La/Yb-REE plots were located near the intersection of basalt, granite and sedimentary rocks. All these characteristics strongly confirmed the existence of hydrothermal sedimentation in the lake.关键词
无机地球化学/古环境/油页岩/延长组/三叠系/铜川地区/陕西Key words
inorganic geochemistry/paleoenvironmental restoration/oil shale/Yanchang Formation/Triassic/Tongchuan area/Shaanxi Province分类
能源科技引用本文复制引用
乔世海,李玉宏,郭望,张云鹏,王勇..陕西铜川地区延长组长7油页岩无机地球化学特征及古环境恢复[J].石油实验地质,2019,41(1):121-126,6.基金项目
国家科技重大专项"西北地区中生界陆相典型页岩气赋存方式与富集规律研究"(2016ZX05034001-006) （2016ZX05034001-006）
陕西省自然科学基金"柴北缘侏罗纪盆地构造演化关键问题研究:以红山地区为例"(2018JM4031)资助 （2018JM4031）
