Twelve reservoir samples from Lower Cretaceous Quantou 4 member in the Songliao basin were selected for 40Ar-39Ar analysis. 40Ar-39Ar age spectra for illite in the sandstone of the Lower Cretaceous Quantou 4 in the Songliao basin were obtained using a purifying system with laser heating. The age indicated by the lower temperature part of the age spectra is younger than the formation age and is older but maybe close to the earliest hydrocarbon charge time. By contrast, the average age indicated by the higher temperature part of age spectra is obviously older than the formation age and represents the age of terrigenous detrital feldspar, which can be used to trace the sediment source. The ages of detrital illite for these samples vary from 107 to 212 Ma, indicating that Quantou 4 member has multiple sediment supplies. Detailed analysis shows that the study region probably has seven source directions.%利用特别研制的纯化装置有效地除弃有机杂质气体,松辽盆地下白垩统泉头组四段砂岩储层伊利石40Ar-39Ar激光阶段加热分析获得了逐渐上升的阶梯型年龄谱.低温阶段伊利石的年龄小于地层年龄,大于但可能接近于油气成藏最早的年龄;高温阶段坪年龄明显老于地层年龄,反映了陆源碎屑伊利石的年龄,用于探讨盆地沉积物的物源.松辽盆地北部下白垩统泉头组四段储层12个样品碎屑伊利石年龄为107～ 212Ma,年龄变化大,具有多物源的特点,据此推断研究区可能存在七个物源方向.
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