南海东北部表层孢粉的分布规律及传输模式  

POLLEN DISTRIBUTION AND THEIR TRANSPORTATION PATTERN IN THE MARINE SURFACE SEDIMENTS OF THE NORTHEASTERN CONTINENTAL MARGIN,SOUTH CHINA SEA,CHINA

作　　者：余少华[1] 陈芳[1] 荆夏[1] 

机构地区：[1]国土资源部海底矿产资源重点实验室,广州海洋地质调查局,广州510075

出　　处：《微体古生物学报》2017年第3期302-319,共18页Acta Micropalaeontologica Sinica

基　　金：国家青年自然科学基金(41506049)资助~~

摘　　要：为了更好地理解南海东北部陆源物质的传输模式以及南海表层孢粉所指示的植被和环境意义,本研究通过对南海东北部273个表层样点进行孢粉分析,采用百分比组合、绝对浓度指标、与离岸最近距离进行定量对比,来揭示南海东北部表层孢粉传输和分布的基本规律。研究显示,南海东北部表层的孢粉属种主要来源以下植被类型,包括红树林,低地和亚低山常绿阔叶林,次生林,低山常绿阔叶林,中山常绿-落叶阔叶混交林,亚高山针叶林。最常见的乔木花粉包括来自次生林群落的松属;其次为来自于低山常绿阔叶林植被的栎属、栲属、罗汉松属、陆均松属、猕猴桃属、金丝桃属以及杜茎山属等。同时还包含少量的中山常绿-落叶阔叶混交林花粉属种,包括鹅耳枥属、桤木属、栗属、枫香属等。最主要的陆源草本为禾本科,其它常见草本包括蒿属、菊科、藜科等。结果显示,南海东北部的表层孢粉主要来源于珠江输入,大型河流输送区域的孢粉沉积浓度超过没有河流输送区域的50倍以上。松属花粉能够被风力携带远距离传播至深海。在表层洋流没有形成涡旋或环流的情况下,会阻挡并削弱花粉沉积,而孢子能够被海流传输携带,珠江口附近高含量的三缝孢子说明了人类活动对自然森林的破坏和珠江携带的水流搬运沉积。在珠江口东边沉积的孢粉组合显示出良好的植被多样性特征,除了以松属花粉为主的次生林以外,以栲属和常绿栎属为主的低山常绿阔叶林组合,和目前华南地区的原生天然植被一致。珠江输送孢粉沉积的最大范围限于120km以内,若没有大型河流传输陆源物质,花粉浓度则在离岸之后急剧降低。对现代表层孢粉浓度和离岸距离的对比,能够定量估算南海东北部冰期时钻孔孢粉与来源地的实际距离,且为推算出冰期时海岸线迁移的幅度提供了线索。In order to understand the pathways of terrestrial input to the oceans and to provide a frame work of the vegetation representation of ocean pollen in South China Sea, 273 surface pollen samples has been retrieved from the northern South China Sea （SCS）, China by using the percentage taxa assemblages, absolute concentration and quan- titative comparison with the nearest shore. Pollen taxa are divided into the groups of mangrove, lowland and sub- mountain forest, forestation, lower mountain evergreen forest, mid-mountain mixed forest and alpine coniferous for- est. The result shows that the most significant arboreal pollen taxa include Pinus （forestation） and many species from lower mountain evergreen forest （ Quercus, Castanopsis, Podocarpus, Darydium, Actinidia, Hypericum and Maesaetc）. Those of^mid-mountain mixed forest taxa are found with small amount （Carpinus, Alnus, Castanea and Liqudambar etc）. The major terrestrial herbaceous pollen is Poaceae. Other frequent herbs are Artemisia, Composi- tae and Chenopodiaceae. The results have showed that the surface pollen in the northeastern SCS is mainly transpor- ted from the Pearl River, where the concentration is more than 50 times than in the absence of river transport. Pinus can be transported further by wind to the deep basin because of its two saccate and the source of pollen in the deep ba- sin is mainly from the wind transport. In the absence of eddy or circle of the surface ocean currents, pollen deposition can be largely impaired, while spores can be transported by ocean currents and survival in the water. The abundance of Trilete around the Pearl River mouth demonstrated that the human activities destructed natural forests and it main- ly transported and deposited by the terrestrial inflowing of the Pearl River. The pollen assemblages deposited on the eastern side of the Pearl River Estuary showed obvious vegetation diversity, which mainly composed by the secondary forests with Pinus, and the lower mountain evergreen broad-leaved forest do

关 键 词：孢粉 风力 洋流 离岸距离 珠江 南海 

分 类 号：Q913.84[天文地球—古生物学与地层学]