论文部分内容阅读
北部湾位于我国南海西北部,是一个半封闭的海湾.在其东部采集了306个表层沉积物样品,对这些样品进行了孢粉分析.据各类植物孢粉浓度(重量浓度)在空间散布的相似程度,将全区孢粉组合划分为5个孢粉区域.据孢粉区域中主要孢粉类型浓度分布的不均匀性,又可划分出4个孢粉浓度高值区和3个孢粉浓度低值区.孢粉浓度沉积的分异与孢粉的来源,海流、潮流、波浪的搬运、沉积作用及海底地形等密切相关.海湾东部海盆边部蕨类植物孢子偏高(东部),松属等木本植物花粉向海盆中心逐渐増多;环岸地带草本植物花粉偏高(北部).对孢粉浓度高值区和低值区的沉积动力环境初步探讨认为,河口是孢粉进入海盆的重要通道,也是主要的沉积场所;潮汐的往返运动,在临岸地带的有利地段可以形成孢粉堆积.海湾尺度的环流有利于孢粉的搬运,但在多种海流交互作用的情况下,往往会造成有利于孢粉堆积的环境.本区东北部是海湾夏季风浪活动最强烈地带,在风浪反复冲刷下孢粉不易沉积,孢粉总浓度低.在琼州海峡内,潮流很强,悬浮物难于沉降,不利于孢粉沉积,形成孢粉浓度的低值区.
Beibu Gulf is a semi-enclosed bay located in the northwestern South China Sea, collecting 306 surface sediment samples in the eastern part of China and carrying out sporo-pollen analysis on these samples.According to the sporopollen concentration (weight concentration) , The pollen assemblages in the whole area were divided into five sporopollen zones.According to the non-uniform distribution of the main sporopollen types in the sporopollen zone, four high sporopollen concentration zones and three spores The distribution of sporopollen concentration is closely related to the source of pollen, current, tidal current, wave handling, sedimentation and seabed topography, etc. The fern spores on the edge of the basin in the east of the Gulf are high (east) , Pine and other woody plant pollen to the basin center gradually increased; the pollen of the herbaceous plants in the coast zone is high (north) .For the preliminary discussion on the depositional dynamic environment of the high value area and the low value area of pollen concentration, Sporadic access to the basin is also a major depositional site; reciprocating tidal movements can form spore-pollen accumulation in favorable locations along the shores. Gulf-scale circulation favors conveyance of sporopollen, but in the case of multiple ocean currents under, In the Qiongzhou Strait, the tidal current is very strong and the tide is very strong. In the Qiongzhou Strait, the tidal current is very strong and the suspension is very strong The material is difficult to settle, is not conducive to the deposition of sporopollen, the formation of low-value sporopollen zone.