长江三角洲北翼后缘晚第四纪以来的沉积粒度特征及环境演化

对长江三角洲北翼CSJA3孔的粒度数据及粒度参数、频率分布曲线和概率累积曲线等沉积物粒度特征进行了详细分析，并结合岩性、沉积构造、孢粉和有孔虫组合等数据，探讨了研究区晚第四纪以来的沉积环境演化及海侵记录。分析表明，粒度数据可以很好地反映沉积环境的变化，间冰期黏土含量降低，砂含量增加，平均粒径较大；冰期正好相反。根据岩性、测年、孢粉、有孔虫等建立的年代框架确定CSJA3孔底部为MIS6期。CSJA3孔自下而上可分为6个沉积单元：U6(泛滥平原—河漫滩)、U5(河口—潮坪)、U4(河漫滩)、U3(潮坪—滨浅海)、U2(河漫滩)、U1(澙湖—潮坪)。CSJA3孔共记录三次海侵，U5、U3和U1地层分别对应MIS5期太湖海侵、MIS3期滆湖海侵和MIS1期镇江海侵。其中，MIS3期海侵强度比MIS5期更大，与全球海平面变化不符。造成这种差异的原因可能是在全球气候变化的大背景下，构造作用控制的古地势变化造成的。

Sediment grain size distribution patterns of the late Quaternary on the back side of northern Yangtze River Delta and their environmental implications

On the north wing of the Yangtze River Delta, grain size data, such as grain size parameters, frequency distribution and the probability accumulation curves, are acquired from the core of CSJA3, in addition to lithology, sedimentary structures, and pollen and foraminifera assemblages. The results support the conclusion that grain size data can effectively reflect the change in sediment environment since MIS6. During the interglacial stage, clay components are getting less as the sand increasing, while the mean grain size becomes coarser. In the glacial stage, however, it is opposed. Six sedimentary environments are recognized from the bottom to top: U6 (flood plain), U5 (river-tidal flat), U4 (river floodplain), U3 (tidal flat-littoral and shallow sea), U2 (flood plain), and U1 (lagoon-tidal flat). Three transgressive layers are found in the core of CSJA3, i.e. layer U5, U3 and U1, corresponding to the Taihu transgression(MIS5), the Gehu transgression(MIS3) and the Zhenjiang transgression(MIS1) respectively. Among them, the MIS3 transgression is larger than MIS5 transgression in scale, which is inconsistent with the global pattern of sea level change, probably caused by tectonism in addition to global climate fluctuation.