摘要
对山西五台山地区早元古代滹沱群连续沉积巨厚的白云岩进行逐层系统的同位素采样分析，发现氧同位素组成非常有规律的分布：在一定的地层层位里，δ^（１８）Ｏ值分布稳定，集中在一个较小的范围内，或δ^（１８）Ｏ值呈连续过渡变化：在不同的地层层位里，δ^（１８）Ｏ值明显不同。笔者认为，早元古代白云岩δ^（１８）Ｏ值这种长期的变化趋势，是古海水氧同位素演变的反映，可作为地层对比的一种标志。
Oxygen isotope compositions of Early Proterozoic Hutuo Group dolomites from the typical profile in Wutaishan Mountain area, Shanxi Province, North China, are reported. The mean sampling interval was 8m and total 484 micritic dolomites were analysed for oxygen isotope. The whole rock dolomite oxygen isotope results show that the δ￣(18)O values distinctly change with geological time, but are relatively stable in certain horizon. The δ￣(18)O values are regularly distributed in the profile studied. It is difficult to interpret theδ￣(18)O variation using dolomite diagenesis. So the trend of oxygen isotope evolution is a reflection of δ￣(18)O change in early Proterozoic sea water. The good relationship between δ￣(18)O and the horizon of strata may provide a new method for carbonate strata correlation in early Proterozoic. There are higher δ￣(18)O values in Beidaxing Formation. The higher δ￣(18)O value is -3.7‰ (PDB) which is 4‰ higher than the highestδ￣(18)O in early Proterozoic dolomites reported.
出处
《地球化学》
CAS
CSCD
北大核心
1995年第C00期83-91,共9页
Geochimica
基金
国家自然科学基金
北京中关村联合分析测试中心资助
