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崇明东滩是典型的河口型沙岛边缘的潮滩地貌,2007年在崇明岛东滩采集了深50m的DT孔岩芯,对崇明东滩DT孔沉积物粒度组成及粒度参数特征分析,并参照该孔沉积物环境磁学参数和有孔虫组合特征,详细阐述了崇明东滩DT孔13.0kaB.P.以来的沉积特征,将DT孔划分出7个沉积层次:该孔沉积水动力强弱变化,自层1→层7依次按较弱→较强→较强→最弱→最强→较强→较弱规律演变;该孔沉积环境自层1→层3为还原环境,层4→层7为氧化环境,且氧化性自下而上逐渐增强。通过对该孔沉积环境综合分析,并与长江口北支CY孔及南汇鹤鸣孔(Hm)沉积环境进行对比分析,得出崇明东滩DT孔所反映的长江口沉积环境演变规律,自层1至层7依次为:滨海沼泽-浅海→河口湾→三角洲前缘→前三角洲→河口沙坝→潮汐水道→潮滩。
Chongming Dongtan is a typical tidal flat on the edge of the estuarine sand island. In 2007, a 50m deep DT core was collected on the east beach of Chongming Island. The sediment particle size distribution and particle size characteristics were analyzed. According to the sedimentary environment magnetic parameters and foraminiferal assemblages, the depositional characteristics of DT hole in Chongming Dongtan since 13.0kaB.P. are described in detail, and the DT holes are divided into seven sedimentary layers: the sedimentary hydrodynamic strong Weak change, from layer 1 → layer 7 followed by weak → strong → strong → weakest → strongest → stronger → weaker law evolution; the hole deposition environment from layer 1 → layer 3 to restore the environment, layer 4 → Layer 7 is an oxidizing environment, and the oxidizing property gradually increases from bottom to top. Through the comprehensive analysis of sedimentary environment of the hole and comparison with the sediment environment of CY hole in North Branch of Changjiang Estuary and Hemian Hole (Hm) in Nanhui, we can get the evolution law of sedimentary environment of Changjiang Estuary reflected by DT hole of Chongming Dongtan, 1 to 7 are as follows: coastal swamp - shallow sea → estuary → delta front → delta → estuary dam → tidal channel → tidal flat.