鄂尔多斯盆地东部下奥陶统白云岩地球化学研究

在岩石学研究的基础上，运用稳定同位素，微量元素，Ｘ射线衍射，阴极发光，扫描电镜及流体包裹体等技术和方法，对鄂尔多斯盆地东部下奥陶统白云岩进行综合研究表明，区内白云岩化具多期叠加的特点，白云岩储集性与白去岩组构，白云岩化程度及白云岩成因密切相关，按成岩阶段可划分为准同生白云岩，成岩（早期和晚期）白云岩和后生（早期及晚期）白云岩（石）其中，准同生白云岩属蒸发泵－渗透回流白云化成因：成岩白云岩早期和晚期

GEOCHEMISTRY OF LOWER ORDOVICIAN DOLOSTONES IN EASTERN ORDOS BASIN

On the basis of lithological data, in terms of stable isotopes of oxygen and carbon, trace elements, X - ray diffraction (XRD), cathodoluminescence (CL), scanning electron microscope(SEM) and fluid inclusions, systematic studies have been made of Lower Ordovician dolostones ineastern Ordos Basin. This study shows that dolomitization in the area studied is characterized byrepeatedly superimposition. The properties of dolostone reservoirs are closely related to dolostonefabrics, dolomitization grade and dolostone genesis. Various genetic dolostones are significantlydifferent in both lithology and geochemistry. According to the diagenetic stages, dolostones in thearea studied can be classified as the following three different types, i. e., penecontemporaneousdolostones derived from evaporitive pumping and seepage - reflux dolomitization during thepenecontemporaneous diagenetic stage, diagenetic dolostones derived from mixing-water dolomitization during both early and late diagenetic stages, and catagenetic ferrodolomites originated fromboth early and late catagenetic dolomitization stages (i. e., early nonvein ferrodolomites and latevein ferrodolomites ).The three main dolomitization models have been established and the relationship betweendolomitization and relevant reservoir properties has been discussed in brief.