Surface pollen distribution patterns in Beibu Gulf and corresponding sediment dynamics environment  

作　　者：TONG GuoBan CHEN Lian LONG JiangPing LI TuanJie XIAO XiaYun TONG SongMei 

机构地区：[1]lnxtituta of Hvdrooeologv and Environmental Geoloev.Chinese Academy of Geological Sciences,Shijiazhuang 050061,China [2]South China Sea Marine Engineering Surveying Center,State Oceanic Administration,Guangzhou 510300,China [3]Second Institute of Oceanography,State Oceanic Administration,Hangzhou 310012,China [4]State Key Laboratory of Lake Science and Environments,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China

出　　处：《Chinese Science Bulletin》2012年第8期902-911,共10页

基　　金：supported by the Chinese Offshore Investigation and Assessment Project (908-01-ZH2);the National Marine Public Welfare Research Project (200805063-3)

摘　　要：The Beibu Gulf is a semi-enclosed gulf in the northwest of the South China Sea.We palynologically analyzed 306 surface sediment samples from the eastern Beibu Gulf to improve bioclimatic interpretation of fossil pollen records there.Surface pollen assemblages could be classified into five pollen regions based on the distributions of total,arboreal,herbaceous and fern pollen concentrations.Four high-concentration and three low-concentration subregions could be distinguished within these regions.The distribution patterns of surface pollen assemblages were consistent with those of grain sizes of surface sediments.Sediments from regions with high pollen concentrations were very fine and fine silts (>7.0,<0.008 mm),whereas those with low pollen concentrations were fine sand (<3.5,>0.088 mm).Sedimentary heterogeneity of surface pollen assemblages was closely related to pollen source,transportation and sedimentation controlled by ocean currents,tides and waves,and oceanic bottom topography.Fern spores exhibited higher percentages along the east margins of the region,while arboreal types like Pinus increased in concentration towards the center.Herbaceous pollen appeared in high percentages around seacoasts near their source areas.Dacrydium and mangrove pollen were distributed near their source regions at low percentages.We discuss the sediment dynamic environments in the eastern Beibu Gulf based on surface pollen distributions.The estuary region is an important access to the sea basin and a depositional site for terrestrial pollen grains.Coastal regions can accumulate pollen due to the back-and-forth movements of tides there.Although ocean currents on a gulf scale tend to spread pollen grains,the interaction of multiple currents could lead to pollen accumulation and deposition.Low surface pollen concentrations in the northeast shallow-water regions of the eastern Beibu Gulf could be attributed to repeated washing and sediment floatation caused by severe wave activities during the summer.Strong tides in Qiongzhou Strait fThe Beibu Gulf is a semienclosed gulf in the northwest of the South China Sea. We palynologically analyzed 306 surface sedi ment samples from the eastern Beibu Gulf to improve bioclimatic interpretation of fossil pollen records there. Surface pollen as semblages could be classified into five pollen regions based on the concentrations. Four highconcentration and three lowconcentration distributions of total, arboreal, herbaceous and fern pollen subregions could be distinguished within these regions. The distribution patterns of surface pollen assemblages were consistent with those of grain sizes of surface sediments. Sediments from regions with high pollen concentrations were very fine and fine silts （〉7.0 , 〈0.008 mm）, whereas those with low pollen con centrations were fine sand （〈3.5 qb, 〉0.088 mm）. Sedimentary heterogeneity of surface pollen assemblages was closely related to pollen source, transportation and sedimentation controlled by ocean currents, tides and waves, and oceanic bottom topography. Fern spores exhibited higher percentages along the east margins of the region, while arboreal types like Pinus increased in con centration towards the center. Herbaceous pollen appeared in high percentages around seacoasts near their source areas. Dacryd ium and mangrove pollen were distributed near their source regions at low percentages. We discuss the sediment dynamic envi ronments in the eastern Beibu Gulf based on surface pollen distributions. The estuary region is an important access to the sea ba sin and a depositional site for terrestrial pollen grains. Coastal regions can accumulate pollen due to the backandforth move ments of tides there. Although ocean currents on a gulf scale tend to spread pollen grains, the interaction of multiple currents could lead to pollen accumulation and deposition. Low surface pollen concentrations in the northeast shallowwater regions of the eastern Beibu Gulf could be attributed to repeated washing and sediment floatation caused by severe wave activities during

关 键 词：花粉浓度 分布格局 北部湾 动力学环境 表面 泥沙 表层沉积物 蕨类植物 

分 类 号：P731.23[天文地球—海洋科学] X513[环境科学与工程—环境工程]