鄂尔多斯盆地西部上二叠统石千峰组沉积环境地球化学表征

在沉积学、生物和地球物理测井相标志研究基础上,运用锶钡质量分数比值和锶钡散点图法,锶钙和钍铀比值法、沉积磷酸盐法、碳氧同位素和氧化-还原电位法等地球化学方法,根据微量元素和稳定同位素的特征对鄂尔多斯盆地西部上二叠统石千峰组沉积时的古盐度和氧化还原条件进行了详细分析。结果表明:石千峰组为淡水沉积,属干旱、炎热、氧化的陆相湖泊环境。其结论与石千峰组的棕红、紫红和紫灰色陆源碎屑岩沉积特别与红色沉积层为特征是相一致的。

Geochemistry Evidence of Sedimentary Environment of Upper Permian Shiqianfeng Formation,Western Ordos Basin

Based on the studying of sedimentary, biology and geophysical log facies and the character of trace ele-ments and stable isotopes, this paper analyzes the paleosalinity and oxidation-reduction condition of upper Permi-an Shiqianfeng Formation of Western Ordos Basin by the geochemistry methods such as Sr/Ba ratio, Sr/Ba dia-gram, Sa/Ca and Th/ U ratios, sedimentary phosphate method, oxidation-reduction method and carbon-oxygenisotope method. The result indicates that the Shiqianfeng Formation belongs to fresh water deposits of terrestriallake in the sedimentary environment of aridity, blazing and oxidation. The conclusion is in concordance with thepresence of brownish red, violet red and violet-grey clastic rock, specially the red sedimentary layer.