A NEW PROBE OF APPLICATION OF SILICON ISOTOPIC δ^(30) Si IN SILICEOUS ROCKS TO SEDIMENTARY FACIES ANALYSIS

The application of isotopic data of carbon (δ 13C), oxygen (δ18O) and sulphur (δ 34S) to the sedimentary facies analysis and environmental study is well known. In contrast, a study on silicon isotopes is rare, although silicon contains major contents of rock-made components in sedimentary rocks. Silicon has three kinds of stable isotooes i. e.

哀牢山硅质岩特征及其意义

“三江”地区哀牢山两类硅质岩的岩性组合、放射虫生态组合、稀土元素（ＲＥＥ）和硅同位素（δ３０Ｓｉ）特征表明，哀牢山晚泥盆世（Ｄ３）硅质岩属浊流成因，沉积于深海环境，证明扬子地台西缘在晚泥盆世（Ｄ３）时已裂开了一个深海槽；早石炭世（Ｃ１）硅质岩属哀牢山蛇绿岩的组成单元，形成于半深海环境，暗示哀牢山蛇绿岩代表的是一个相对封闭的小洋盆；海水深度、氧逸度条件、陆源物质及火山物质是影响哀牢山硅质岩稀土组成和硅同位素组成的因素。