摘要
为示踪辽东凹陷LD29-1构造沙二段(Es_2)砂岩沉积,对LD29-1-1、LD29-1-1Sa及LD29-1-2等3口井的沙二段砂岩6个岩屑样品进行了碎屑锆石U-Pb定年和锆石阴极发光(CL)图像分析。结果表明:LD29-1-1井样品中白垩纪(K)锆石含量高达41.2%,具有108 Ma峰值年龄,锆石柱状晶形完整,并且棱角明显;而LD29-1-1Sa及LD29-1-2井样品的中元古代(Pt_2)锆石含量高达74%～75%,中生代(Mz)锆石含量少,具有～1.5 Ga和～1.8 Ga双峰值特征,锆石晶体明显小于LD29-1-1井沉积物,并且晶形不完整、边缘均被磨圆。因此,认为LD29-1-1井沙二段砂岩为近源沉积,母岩为长兴岛凸起斜坡带中生界碎屑岩,而LD29-1-1Sa及LD29-1-2井沙二段砂体为远源沉积,母岩以辽东半岛西部复州地区广泛分布的中、上元古界沉积岩为主,在搬运至斜坡带时才混入少量中生界碎屑岩。
To trace the sedimentary source-to-sink systems of the Lvda 29-1 structure in the eastern Bohai Sea,six sandstone cuttings of the second Member of Shahejie Formation(E s 2)were collected from LD29-1-1,LD29-1-1Sa and LD29-1-2 for detrital zircon U-Pb dating and cathodoluminescence(CL)image analysis.The results showed that the sandstones of LD29-1-1 contained 41.2%Cretaceous(K)zircons and featured a 108 Ma peak,and the columnar crystals were characterized by sharp edges.The LD29-1-1Sa and LD29-1-2 sandstones contained 74%-75%Mesoproterozoic(Pt 2)zircons with peaks at^1.5 Ga and^1.8 Ga,and the broken crystals were well rounded.We concluded that the E s 2 sandstones of LD29-1-1 were near-source deposited,and the provenance was the Mesozoic sedimentary rocks along the slope of the Changxingdao Uplift;the E s 2 sandstones of LD29-1-1Sa and LD29-1-2 were distal from the source area and were dominated by the widespread Mesoproterozoic and Neoproterozoic sedimentary rocks exposed in Fuzhou on the western Liaodong Peninsula,with only a slight influence of Mesozoic sedimentary rocks from the slope of the Changxingdao Uplift.
作者
赵梦
杜晓峰
王清斌
冯冲
庞小军
李欢
ZHAO Meng;DU XiaoFeng;WANG QingBin;FENG Chong;PANG XiaoJun;LI Huan(Bohai Oilfield Research Institute,China National Offshore Oil Corporation,Tianjin Branch,Tianjin 300459,China)
出处
《沉积学报》
CAS
CSCD
北大核心
2019年第1期62-71,共10页
Acta Sedimentologica Sinica
基金
国家科技重大专项(2016ZX05024003)~~
