石油实验地质2016，Vol.38Issue(6)：828-835,8.DOI:10.11781/sysydz201606828
沉积条件下白云石与伴生方解石碳氧同位素组成的差别及影响因素
Differences and controls of carbon and oxygen isotope composition in dolomite and coexisting calcite under deposition conditions
摘要
Abstract
We discussed the composition and factors influencing carbon and oxygen isotopes in dolomites and coexis⁃ting calcites in hand specimen mesoscale based on petrography and combined with elemental, X⁃ray diffraction and carbon and oxygen isotope analyses. Results indicated that dolomites have higherδ13 C andδ18 O values than coexisting calcites. Two factors may account for the higherδ18O values of dolomites. (1) The oxygen isotope fractionation factors of a dolomite-water system are higher than those of a calcite-water system. Therefore, oxygen isotope fractionation factors are greater than 1 in a dolomite-calcite system. (2) The fluids of dolomite precipitation have higher salinity and higher 18 O abundance compared to coexisting calcite. In addition, the δ13 C values of dolomites show the same trends withδ18 O values. That is to say, the carbon isotope fractionation factors in a dolomite-CO2 system are higher than those in a calcite-CO2 system. Therefore, carbon isotope fractionation factors are greater than 1 in a dolomite-calcite system during replacement process. Oxygen isotope values varied obviously between syndepositional dolomites and coexisting calcites, while they were similar between hydrothermal/deeply burial dolomites and coexisting calcites.关键词
分馏系数/碳氧同位素/伴生方解石/白云石Key words
fractionation factors/carbon and oxygen isotope/coexisting calcite/dolomite分类
能源科技引用本文复制引用
李小宁,黄思静,黄可可,钟怡江,胡作维..沉积条件下白云石与伴生方解石碳氧同位素组成的差别及影响因素[J].石油实验地质,2016,38(6):828-835,8.基金项目
国家自然科学基金项目（41272130）“川渝地区早三叠世海相碳酸盐岩的碳同位素研究”资助。 （）
