古地貌对新安堡凹陷万一段层序地层沉积控制规律研究

为弄清古地貌对伊通盆地新安堡凹陷古近系万昌组一段层序地层发育时沉积控制规律,首先应用层序地层学原理把万昌组一段划分为完整的三分体系域,即低位体系域、湖侵体系域和高位体系域,然后对不同体系域沉积前的古地貌进行分析,预测其物源方向及沉积物搬运路径,最后结合波形聚类明确了不同体系域沉积相平面展布。认为:低位体系域沉积时期,物源最为充足,沉积物体积向盆地中心方向增加,砂体在全区都较发育;湖侵体系域沉积时期,物源开始减少,沉积物体积向盆地边缘方向增加,砂体在凹陷的东南缘较为发育;高位体系域沉积时期,物源开始增加,沉积物体积向盆地中心及西北缘方向开始增加,砂体在凹陷的西北缘较为发育。

The Research of the Control Rules of Palaeogeomorphology on Sequence Stratigraphy of the First Member of Wanchang Formation in Xinanpu Sag

To find out the control of palaeogeomorphology on sequence stratigraphy of the first member of wanchang formation of paleogene in Xinanpu sag of Yitong basin.First of all,based on the sequence stratigraphy principle,the first member of wanchang formation has been divided into a complete set of three systems tracts, namely the lowstand system tract,the transgressive system tract,and the highstand system tract.And then,the provenance direction and sediment transport path have been predicted by analyzing the palaeogeomorphology before different systems tracts deposition.Finally,Combined with waveform cluster,it can confirm the plane distribution of sedimentary facies in different systems tracts.Through the synthetic analysis above,the authors have found that during lowstang system tract position,provenance was most abundant,sediment volume increased toward the basin center,and sand body widely developed in the area.During transgressive system tract position,provenance began to decrease,sediment volume increased the toward the basin edge,and sand body developed in the southeast of Xinanpu san.During highstand system tract position,provenance began to increase,sediment volume increased toward the basin center and the northwest of Xinan pu sag,and sand body developed in the northwest of Xinanpu sag.