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鄂尔多斯盆地奥陶系马家沟群的块状白云岩，按晶粒结构可分为细砂糖状白云岩（晶粒大小为０．０１—０．１ｍｍ）和粗砂糖状白云岩（晶粒大小为０．０５—０．２５ｍｍ）。包体分析为块状白云岩的成因研究提供了最直接的信息。细砂糖状白云岩的主体白云石中液态包体不发育，但孔隙充填方解石中的包体发育，由２４个孔隙充填方解石中的包体测出的均一温度为４９—７４℃，测算的包体形成深度的最大值为１７２ｍ。由此可以推断，其主体白云石应形成于埋深小于１７２ｍ的浅埋藏环境。粗砂糖状白云岩的主体白云石中液态包体发育，激光拉曼光谱分析测得的包体成分中普遍含有甲烷（ＣＨ４）等有机成分，说明这类包体形成于深埋藏的有机质干气演化阶段。所测的包体均一温度的最低值为１０４℃（未经压力校正），由此测算的包体形成深度的最小值为２６００ｍ。由此可见，粗砂糖状白云岩形成于埋深不小于２６００ｍ的深埋藏热水白云化环境。
The massive dolomites of the Ordovician Majiagou Group in Ordos Basin can be divided into fine granulated dolomite (grain size of 0.01-0.1mm) and coarse granulated dolomite (grain size 0.05-0.25 mm). The inclusion analysis provides the most direct information for the study of the genesis of massive dolomites. The liquid inclusions in dolomite, the main dolomite, are not well developed. However, the inclusions in the pore-filled calcite are developed. The homogenization temperature is 49-74 ℃ from the inclusions in 24 pores filled calcite. The calculated inclusions The maximum depth of formation is 172 m. It can be inferred that the main dolomite should be formed in a shallow buried environment buried less than 172m. The liquid inclusions in dolomite, the main dolomite of the coarse-grained dolomite, are developed. The composition of the inclusions measured by laser Raman spectroscopy generally contains organic components such as methane (CH4), indicating that these inclusions are formed in deep buried organic matter Evolution stage. The lowest value of the homogenization temperature of the inclusions was 104 ℃ (without pressure correction), and the minimum depth of inclusions was 2600m. Thus, the coarse granulated dolomite formed in buried depth of not less than 2600m deep buried hot water dolomization environment.