【摘要】 利用多只见及基岩的钻孔,以岩石地层为基础,结合气候—生物地层、磁性地层和年代地层等多重地层划分,对上海地区晚新生代松散地层进行了系统的划分与对比,厘定了区内第四系下限及各内分地层单位的界限。在系统阐述上新世以来沉积环境演化的基础上,对上海地区晚新生代沉积模式进行了探讨:前期,由上新世—早更新世早期的陆相环境演化为早更新世中期-中更新世的以陆相为主间或为海陆过渡相环境,形成以陆相杂色硬粘土为主的地层序列;后期,晚更新世以来演化为海相和海陆过渡相为主的沉积环境,形成灰色砂、粉土和软粘性土占优势的地层序列。更多还原

【Abstract】 Based on a few boreholes piercing bedrocks in Shanghai,multi-methods including lithostratigraphy,biostratigraphy,magnetic stratigraphy,and chronostratigraphy are used to subdivide and spacially correlate the local Late Cenozoic unconsolidated sequences.As results,the lower limit of the Quaternary and limits of its subdivisions were determined in the study area.Combined with the systematic analyses of the sedimentary environmental evolutions since the Pliocene,the local Late Cenozoic sedimentary models were discussed.In the preliminary phase,the local sedimentary environment was characterized by continental facies during Pliocene to early Early Pleistocene,and it was evolved into continental facies jigged with continental-marine alternating facies during the middle Early Pleistocene.In this phase,mottle firm clay of continental facies was formed.In the latter phase after Late Pleistocene,the sedimentary environment was evolved into marine facies,jigged with continental-marine alternating facies,its sedimentary sequence was prominently characterized by grey sand,silt and soft clay.更多还原