内蒙古白云鄂博群中微生物岩的发现及其地质意义

THE DISCOVERY OF MICROBIOLITE IN THE BAYAN OBO GROUP OF INNER MONGOLIA AND ITS GEOLOGICAL SIGNIFICANCE

白云鄂博群的微生物岩Ｍｉｃｒｏｂｉｏｌｉｔｅ主要位于其中部Ｈ＿６－Ｈ＿８岩段（哈拉霍疙特组）。在Ｈ＿６岩段中下部可见到典型的凝块石层位，其形态与柱状叠层石的形象差不多，产在钙质砂岩或砂质灰岩中。Ｈ＿７岩段主要为不发育的微小型叠层石层位。Ｈ＿８岩段上部约５０～６０ｍ部分是最主要的微生物岩层位。主要产出微小型叠层石和凝块石等；而核形石的形体较大，多呈放射状。微生物泥丘为黑色的丘状体，大小不一，产于碳酸盐层位中。微生物岩与石油天然气的形成有密切的联系。

Microbiolite of the Bayan Obo Group mainly occurs in Menbers H_6-H_8(Halahuogete Forma-tion)in the middle part of the group.In the middle and lower parts of Member H_6 ,we can see thetypical thrombolite horizon. Its form is almost the same as that of columnar stromatolite occurringin calcareous sandstone or sandy limestone. Member H_7 is chiefly a less developed ministroma-tolite horizon. The top 50-60 m interval in the upper part of Member H_8 is the main microbiolitehorizon ,yielding microstromatolite and thrombolite. The size of oncolite , however ,is bigger andmostly radiate in shape. Microorganism mud mounds are black mounds and variable in size occur-ring in the carbonate gorezon. Microbiolite is intimately associated with the formation ofpetroleum.