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对长江三角洲DY03孔3.6Ma以来的沉积物碎屑锆石样品利用LA-ICP-MS进行了U-Pb年龄测定.结果表明,DY03孔189.8～215.8m之间(磁性地层年龄3.2～3.5Ma)沉积物碎屑锆石年龄以100～150Ma占优势,沉积物主要来自长江下游地区的白垩纪岩体,物源区比较局限;189.8m(~3.2Ma)以上沉积物碎屑锆石年龄呈现多峰态分布的特征,主要分布于100～300,350～550,600～1000,1400～2000和2200～2800Ma,表明沉积物源区显著扩大.从DY03孔3.2Ma以来沉积物碎屑锆石中识别出大量来自长江上游的年龄信息,表明当时长江沉积物已开始影响到三角洲地区.考虑到古长江在上新世以前有可能没有流经现在的长江三角洲,而是流向苏北盆地,长江贯通的时限应不晚于3.2Ma.
U-Pb dating of sediment detrital zircon samples from the DY03 hole in the Yangtze Delta for 3.6 Ma has been done by LA-ICP-MS. The results show that the age of the DY03 is between 189.8 and 215.8 m (the age of the magnetic strata is between 3.2 and 3.5 Ma) The age of sedimentary detrital zircons is dominated by 100-150 Ma, and the sediments mainly come from the Cretaceous rock mass in the lower reaches of the Yangtze River. The source areas of the detrital zircons are relatively limited. Detrital zircons ages of 189.8 m (~ 3.2 Ma) The distribution of kerogen is mainly distributed in the range of 100-300, 350-550, 600-1000, 1400-2000 and 2200-2800 Ma, indicating a significant increase of sedimentary source area. A large number of sedimentary debris zircons have been identified from The age information of the upper reaches of the Yangtze River indicates that the Yangtze River sediments started to affect the delta region at that time.With the fact that before the Pliocene the ancient Yangtze River might not flow through the present Yangtze River Delta but flow to the Subei Basin, Later than 3.2Ma.