江苏王港潮间带柱状样的压缩和校正

Calibration for Intertidal Flat Sediment Core Shortening :a case study from Wanggang,Jiangsu Coast

潮滩盐沼是海岸系统的重要组成部分,是海岸带陆海相互作用研究的重点对象之一。研究潮滩沉积环境和沉积过程的传统的、主要的手段是采集柱状样;在潮间带采集柱状样一般采用重力采样法,在采集过程中会产生管内压缩和管下压缩。在江苏中部王港地区的潮间带,利用重力方法取得9个柱状样,在现场采样时记录了采样管内外深度,在室内对采集的样品利用激光粒度仪进行粒度分析。根据野外记录和室内分析结果,管内压缩和管下压缩均为线性过程;管内压缩率与沉积物含水量及沉积物分选性有关,含水量越高,压缩率越大,沉积物分选越差,压缩率越大。管下压缩量是管内压缩量的11%,随着管内压缩率的增大,管下压缩量也增大,管下压缩所起的作用就越显著。

Tidal salt-marshes represent an important part in a coastal wetland system,and it also becomes a key study objective of land-ocean interaction in coastal zone due to the marked human activities and the sensitivity of the areas in response to global change. Sediment cores as a h-aditional and primary instrument for studying the sedimentary environments and depositional processes of tidal flat are taken generally by gravity corer in inter-tidal flat. Wherever sediment cores were collected by gravity corer, the length of the cores became shorter than the original length, and this compaction processes take place not only inside the.sampling tube but also beneath the bottom of the sampling tube. Nine sediment cores were collected by gravity method in the inter - tidal flat of Wanggang which is located on the central coastline of Jiangsu Province, the depth variations of sampling tube were recorded in situ,and the samples were analyzed for grain size by a laser particle analyzer in laboratory. According to the field records and analysis results indoor, both compactions taking placing inside and beneath the sampling tube are linear process;the compaction ratio inside the sampling tube relate to water content of sediment and sorting coefficient, viz. the higher water content and the worse sorted, the higher compaction ratio. According to the calculated results, the length of the compaction beneath the sampling tube is 11% as much as that inside, the compaction length beneath the sampling tube increases with the in- creasing of compaction ratio inside, and the function of compaction taking placing beneath the sampling tube is more remarkable.