东北太平洋CC区表层沉积物中的微体生物化石研究

STUDY OF MICROFOSSILS IN THE SURFACE SEDIMENTS FROM THE CC AREA OF THE NORTH EAST PACIFIC OCEAN

本区表层沉积物中的微体生物化石丰富，且分异度较高，反映了热带大洋高生产力的特点。另一方面，保存于海底沉积物中的不同的地质时期的微体生物化石都代表着一段沉积的历史，本文通过对表层沉积物中不同的微体化石的组合特征与分布规律的研究，揭示了该区表层沉积物的沉积类型、沉积特点以及它们与微体化石之间的关系。

Through studying microfossils in the surface sediments from the CC investigation area of the North East Pacific Ocean,we recognize the following characteristics: 1)Microfossils in the surface sediments from the CC investigation area are abundant and diversities great.142 genera and 199 species of Radiolaria,17 genera and 28 species of diatom and 9 genera(families)of sporopollen are found. 2)Radiolaria abundance is the highest among the microfossils.According to ecologic characters and assemblages of living radiolaria and other reference data,the Radiolaria in the investigation area may be divided into 4 different types:tropical species,subtropical species,temperate species and high latitude species. 3)Microfossils of the surface sediments in the east area show Quaternary biologic assemblages,and thus reflect Quaternary sediments.In the middle and north of the west investigation area,microfossils in the surface sediments are proved to be relict sediments and sediments in the south are melange accumulations. 4)Contents of siliceous microfossils are greatly different in different sediment types from the CC investigation area.Analysis results show 37% of siliceous microfossils in siliceous ooze,17 2% in siliceous clay,5%～10% in clay with silica and about 4% in calcareous clay.