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鄂尔多斯盆地上古生界有石炭－二叠系煤系和石炭系碳酸盐岩两套气源岩，其中前者对天然气的生成贡献最大。古地质温度计测温和古地温场模拟计算结果显示出，在晚侏罗世－早白垩世存在异常高地温场，使盆地古地温场和热流值均远高于现今值。受古地温场演化史的控制，天然气的生成具有侏罗纪之前深成变质作用控制下的生烃演化，早、中侏罗世深成变质作用和局部热异常控制下的生烃演化，晚侏罗世－早白垩世深成变质作用和区域热变质共同控制下的生烃演化及早白垩世之后降温过程下的生烃演化4个阶段；相应的烃源岩在晚三叠世局部开始进入生烃门限，之后随生气量的逐渐增加，生烃范围不断扩大，至早中侏罗世开始有少量天然气的排出，晚侏罗世受燕山中期异常热事件的强烈影响，在晚侏罗世－早白垩世达到生排气高峰期。并最终形成以东部为主、西部次之的广覆式资源分布特征。

Natural Gas Generation in the Upper Paleozoic in E'erduosi Basin

??There are two sets of gas source rocks,i.e.Carboniferous-Permian coal measures and Carboniferous carbonate rocks,in the Upper Paleozoic in E'erduosi Basin,in which the former has made the largest contribution to the natural gas generation.According to the results of the geotemperature measure by palaeogeological thermometer and the simulation calculation of palaeogeothermal field,it is shown that the existence of abnormal high palaeogeothermal field in the Late Jurassic-Early Cretaceous made that the values of palaeogeothermal field and ancient thermal current were much higher than those found at present.Controlled by the evolutional history of the Palaeogeothermal field,the natural gas generation was undergoing four stages,i.e.the hydrocarbon generation evolution controlled by hypometamorphism before the Jurassic;that controlled by hypometamorephism and local thermal anomalies in the EarlyMiddle Jurrasic;that controlled jointly by hypometamorphism and regional thermal metamorphism in the Late Jurassic-Early Cretaceous and that controlled by the process of lowering the geotherm after the Early Cretaceous.Correspondingly,the hydrocarbon source rocks started out to enter into the hydrocarbon generationt hreshold in the Late Triassic,then the scope of hydrocarbon generation unceasingly enlarged along with a gradual increase in gas generating qantity.Up to the beginning of the Middle Jurassic,a little natural gas was squeezed out,then the peak gas generation and expulsion periods occurred in the Late Jurassic-Early Cretaceous owing to a strong influence of the abnormal thermal event in middle Yanshan epoch of the Late Jurassic and then a wide-covered resource distribution property (being mainly distributed in the east,then the west)was formed finally.