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文中对上海奉贤DY03孔222m长的沉积物柱状样样品进行有孔虫定量统计分析,结合颗石藻、孢粉等其它古生物学资料,重建了晚新生代长江三角洲南部沉积环境变化。钻孔孔深60m以上发现有孔虫产出,包括60—40m与24.6—2m两层位,尤以24.6—2m有孔虫丰度较高。孔深60m附近有孔虫丰富,底栖有孔虫主要属种为Ammonia beccarii vars.,Nonionella stella,Protelphidium tuberculatum,Elphidium advenum和Astrononion tasmanensis等,而58.8—49.2m则不含有孔虫;孔深48.8—40m,有孔虫丰度、分异度均从下而上降低,从以Ammonia beccarii vars.-Elphidium advenum组合为主,Ammonia compressiuscula,Florilus decorus,Pseudononionella variabilis及Nonionella stella等繁盛的面貌,变为仅含少量的Ammonia beccarii vars.和Elphidium limpidum等。有孔虫群落在60—40m层位呈现了其沉积环境由滨岸演变为浅海、又转变为滨岸的演化序列。另一有孔虫丰富层位(埋深为24.6—2m)中,有孔虫分布连续、丰度高、属种分异度高,其中下部21.4—8.8m含有大量的低盐种Pseudononionella variabilis,Stomoloculinasp.以及少量Heterolepaspp.和Lagena hispida;中部8.4—5.0m产出大量深水型分子Ammonia compressiuscula及代表高温、高盐环境的瓷质类型Quinqueloculina seminula,Triloculina rotunda和Spiroloculina laevigata;上部4.8—2m中深水类型缺失,从下至上显示了一个海水由浅到深再变浅、海水盐度由低到高再变低、海水温度由低到高再变低的海侵-海退过程,且本次海侵较上次海侵水深更深、范围更广。对比显示,DY03孔24.6—2m地层相当于中国东部广泛存在的第一海侵层(全新世),而60—40m地层则相当于第二海侵层(晚更新世),有孔虫等生物群落演化反映了该地区晚更新世以来的两次较大海水进退过程。
In this paper, the quantitative analysis of foraminifera from 222m long sediment column in Fengx03, Fengxian, Shanghai, combined with other palaeontology data such as coccolith, pollen and so on, reconstructed the sedimentary environment in the southern Yangtze River delta in the Late Cenozoic. Borehole depth of more than 60m found foraminiferal output, including the two layers of 60-40m and 24.6-2m, especially 24.6-2m foraminifera abundance higher. The major species of benthic foraminifera were Ammonia beccarii vars., Nonionella stella, Protelphidium tuberculatum, Elphidium advenum and Astrononion tasmanensis, while the 58.8-49.2m did not contain foraminifera. The depth of hole was 48.8 -40m, foraminifera abundance and differentiation decreased from the bottom up. From the combination of Ammonia beccarii vars.-Elphidium advenum, Ammonia compressiuscula, Florilus decorus, Pseudononionella variabilis and Nonionella stella, Only a small amount of Ammonia beccarii vars. And Elphidium limpidum and so on. The foraminiferal community in the 60-40m layer presents the evolutionary sequence of the sedimentary environment evolved from the coast to the shallow sea and into the coast. In another rich layer of foraminifera (depth 24.6-2m), the distribution of foraminifera is continuous, with high abundance and high species diversity. The lower part of 21.4-8.8m contains a large amount of low-salt species Pseudononionella variabilis, Stomoloculinasp and a small amount of Heterolepaspp. And Lagena hispida; a large amount of deep-water molecular Ammonia compressiuscula and a porcelain type Quinqueloculina seminula, Triloculina rotunda and Spiroloculina laevigata representing high temperature and high salinity environment were produced in the middle of 8.4-5.0m; From bottom to top, we can see a process of transgression-regression of seawater from shallow to deep and shallow, salinity of seawater from low to high and then low, and sea water temperature from low to high and then low again, The depth of the previous transgression was deeper and wider. The comparison shows that the 24.6-2 m formation of DY03 boreholes corresponds to the first transgressive layer (Holocene) widely present in eastern China, while the 60-40 m strata corresponds to the second transgressive layer (Late Pleistocene), to foraminifera and other organisms The evolution of the community reflects two major sea-water advances and withdrawals since the late Pleistocene in the area.