吉林省东部石炭-二叠系伊利石的成因标志

吉林东部石炭-二叠系主要是一套泥质岩石, 其详细深入的矿物学工作尚不多见。利用JSM-6700F场发射电镜及INCA能谱仪，研究了伊利石的显微形貌和微区成分。采用D/max-2500 X-射线衍射仪，研究了伊利石的结晶度、多型和b₀值。结果表明:研究区伊利石结晶度变化于0.26~0.77，平均值为0.44；伊利石（白云母）多型有3种类型，分别为1M_d型、1M_d+2M₁混合型和2M₁型；伊利石（白云母）b₀值为8.996~9.045，平均值为9.007Å。石炭系伊利石结晶度变化于0.26~0.50，平均值为0.35，主要呈2M₁多型，b₀平均值为9.011Å，主要是低级近变质带的产物；二叠系伊利石结晶度变化于0.26~0.50，平均值为0.42，主要为1M_d+2M₁混合型多型，b₀平均值为9.004Å，主要为晚期成岩带的产物。

Genetic Chariciterics of Illite in the Carboniferous-Permian Pelitic Rocks in East Jilin Province

The Carboniferous-Permian strata in east Jilin is mainly composed of pelitic rocks for which no detailed mineralogical research works have been done up to now. By using JSM-6700F field emission scanning electron microscope and INCA EDS, the authors focused on the micro-morphology and composition of illite, the most important clay mineral of the pelitic rocks. The crystallinity, polytype and b₀ dimension of illite were measured using a D/mas-2500X-ray diffractometer. The illite crystallinity  ranges from 0.26 to 0.76 and  averages at 0.44. The illite polytype of (muscovite) is featured by 1M_d, 1M_d+2M₁ and 2M₁ types. The illite(muscovite)  b₀ mension  ranges from 8.996Å to 9.045Å  and averages at 9.007Å . The illite crystallinity of the Carboniferous rocks ranges from 0.26 to 0.50,averages at 0.35. Their polytype is predominantly 2M₁, averaged b₀ dimension is 9.011Å . These results suggest that the Carboniferous rocks probably were formed in a low anchizone. In contrast, the illite crystallinity of the Permian rocks ranges from 0.26 to 0.50, averages at 0.42, its polytype is mainly 1M_d+2M₁, mean b₀ dimension is 9.004Å , indicating a late diagenetic zone.