鄂尔多斯盆地奥陶纪蒸发岩系有机地球化学研究

鄂尔多斯盆地之陕北盐盆赋存有巨厚的奥陶纪石盐矿层。对其含盐系有机地球化学的研究 ,尤其是对生物标记化合物的研究表明 ,盐层中有丰富的氯仿沥青A、有机碳、饱和烃、芳烃等有机化合物的分布。通过对可溶有机质饱和烃详细研究得出结论 ,认为 :Pr/ph值低、藿 /甾值高、β -葫罗卜烷、γ蜡烷、孕甾烷、升孕甾烷等均有分布。这反映了盐岩层形成于高盐度和强还原以及富含菌藻类水生生物的沉积环境。运用有机地球化学对含盐系进行系统研究有着重要的意义。这一方面可以了解盐类沉积的古环境 ,另一方面可以深刻认识生物在盐类沉积中的作用 ,以探索找盐找钾的生物标记化合物指标。

ORGANIC GEOCHEMISTRY OF ORDOVICIAN EVAPORITE IN EERDUOSI BASIN

The North Shaanxi salt depression of the Eerduosi basin has developed greatly thick Ordovician halite beds which, shown by studies of their organic geochemistry, contain rich organic compounds such as chloroform bitumen A, organic carbon, satisfied hydrocarbon, etc. Conclusion here comes from research on the dissoluble organic materials like satisfied hydrocarbon that they are characteristic of lower Pr to ph ratio, higher patchulane to stane ratio, and different amounts of β carotane, γ sirotirane, pregnane and sublimation pregnane. This character indicates that the conditions necessary for forming salt beds were salinity high, reducing and thallogen rich. Studies of the organic geochemistry of the salt beds are of a lot importance, for one thing, we can make clear their old sedimentary environments and, for another, role of organism in salt deposition so as to work out which organic compounds can be used as marks for exploring salt and potassium resources.