Two Kinds of deltas-meandering stream-shallow sea delta andbraided stream-shallow lake delta-developed in Permo-carboniferous Systems in Ordos Basin.The deltas differ from typical deltaic model.Deltaic front subaqueous distributary channel sand bodies and deltaic plain distributary channel sand bodies are the skeleton sand bodies of meandering stream-shallow sea delta and braided streain-shallow lake delta respectively but not tranditional deltaic front river mouth sand bars.The two kinds of deltas are controlled by river types,ground slope,water depth,water density differentia,river sedimentation and lake dispersion.The first kind of delta mainly developed in meandering stream water system;the second kind of delta developed in braided river water system.Two depositional models were built according to their characteristics.It is pointed out that the subaqueous distributary channel sand bodies of the first type of delta and the lensing and zonal distributary clannel sand bodies of the second type are favourable oil and gas exploration targets.%鄂尔多斯盆地中部石炭二叠系发育曲流河浅水海相三角洲和网状河浅水湖泊三角洲两种类型的三角洲。这两类三角洲与经典的三角洲模式不同的是，三角洲前缘水下分流河道砂体和三角洲平原分流河道砂体分别构成了曲流河浅水海相三角洲和网状河浅水湖泊三角洲的骨架砂体，而不是传统认为的三角洲前缘河口砂坝。控制石炭二叠系两类三角洲发育的主要是河流类型、地形坡度、水体深浅、不同水体密度差及河流沉积作用和湖泊的分散作用等。曲流河浅水海相三角洲主要发育于曲流河水系，沉积物较细，地形坡度平缓，喷流机制为似等密度流，水体密度较大，以河流、波浪和潮汐作用为主；网状河浅水湖泊三角洲主要发育于网状河水系，沉积物较粗，地形坡度较小，喷流机制属高密度流，水体密度较小，湖泊分散作用较强，沉积作用相对较弱。根据两类三角洲的特征分别建立了它们的沉积模式，并指出曲流河浅水海相三角洲前缘水下分流河道砂体及网状河浅水湖泊三角洲的平原相带呈透镜状或带状分布的分流河道砂体是有利的勘探方向和目标。
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