川北303地区砂岩型铀矿含矿层位高分辨率层序研究

根据地层的沉积特征,利用钻孔、野外露头剖面等资料,按照基准面旋回结构和叠加样式特征,将川北303地区砂岩型铀矿苍溪组含矿段划分为5~8个短期基准面旋回,3个中期基准面旋回。通过精确的单井层序地层划分及研究区连井对比,建立了303地区下白垩统苍溪组含矿段的层序地层格架。并对层序地层与砂岩型铀成矿关系进行了探讨:铀矿主要富集于侵蚀基准面之上的低水位体系域主河道砂体的展布方向上,铀矿化主要发育于河道滞留沉积顶部、心滩亚相底部。根据以上研究成果,认为研究区层序地层的发育对铀成矿具有一定的控制作用。

High Resolution Sequence Stratigraphic Study of Sandstone Type Uranium Deposit in Area 303 in the North of Sichuan Basin

Based on the drilling data,outcrop section data and the sedimentary characteristicsof formation,the sandstone type uranium deposit of ore-bearing layer in Area 303 which locate in Lower Cretaceous Cangxi formation was divided into 5~8 short-term base level cycle,3 mid-term base-level cycles according to the superposition of base level cycle structure and style characteristics.In this paper,the stratigraphic framework of Lower Cretaceous Area 303 was established by means of the accurate single-well sequence stratigraphic classification and well conjuction in the research area.The relationship between sequence stratigraphy and sandstone type uranium mineralization were discussed in this paper.Uranium deposits are mainly concentrated in the distribution direction of the main channel sand bodies in the low water level system tracting above the erosion base level,while uranium mineralization is mainly developed at the top of channel retention deposition and the bottom of the core bank subfacies.Based on the above research results,the author believed that the development of sequence stratigraphy in the study area has a certain controlling effect on uranium mineralization.