三种沉积环境中有机粘土复合体特征比较

选取长江三角洲地区潮滩、太湖沉积物以及埋藏的浅海相泥质沉积物样品,运用无机溶液与超声分散结合的方法,提取有机粘土复合体;运用X衍射分析、粒度分析、有机元素分析等多种测试方法来比较、研究这三种沉积物中有机粘土复合体的特征.结果表明,三种不同沉积环境中提取出来的有机质组成并不相同;粘土矿物主要以伊利石为主,其次为绿泥石和高岭石;浅海相粘土粒级沉积物结合的有机质最多,湖泊相沉积物结合得最少.这种规律可能与沉积物中有机质的降解过程和结合形态有关.海相沉积物经历了一定的埋藏压实过程,有机质遭受早期成岩作用影响,紧结态有机质较多,即有机质与粘土矿物结合较牢固,从而不易从粘土矿物中释放出来;而湖泊相沉积物中,轻组有机质或松结态有机质较多,即有机质与粘土结合得较松散,从而容易从粘土矿物中释放出来.

Comparison of Organo-Clay Complex in Three Sedimentary Environments

The sediments formed in different sedimentary environments were collected for the comparative study of organo-clay complex.The clay fractions were separated from the bulk sediments and then were processed to extract the organo-clay component.The organo-clay complexes were characterized in terms of clay mineral and organic elemental compositions by using elemental analysis and XRD.The results show that elemental compositions of organic matter are different between three sedimentary environments,whereas the clay minerals are dominated by illite,and kaolinite and chlorite are subordinates.According to the organic elemental compositions and the compound degree of organo-clay complex,we deduce that the shallow-marine sedimentary environment experienced stronger early diagnesis,which results in the fact that the organic matters were tightly combined with clay and difficult to release.In comparison,the complex of organic matter with clay in lake sedimentary environment is weak and organic matters are easy to be extracted by alkaline solutions.