南极普里兹湾沉积物中生物硅对粒度测量结果的影响

为了探讨生物硅对沉积物粒度测量结果的影响, 本文采用两种不同前处理方法对普里兹湾重力柱状样品进行了粒度测试。结果表明, 生物硅对沉积物的平均粒径以及黏土、粉砂、砂组分的影响较小, 而对沉积物的分选、偏态、峰态以及粒度频率分布的影响较显著。结合两组粒度组分相关性分析以及各粒级含量累积减小值, 认为生物硅对沉积物中砂、粉砂、黏土级组分含量的影响逐渐减小, 这也造成未去除生物硅的沉积物粒度测量结果偏粗。另外, 通过对比发现普里兹湾沉积物中生物硅粒径主要分布在<3Φ、5.25Φ—7.25Φ、8.75Φ—9.75Φ的粒径范围。极地研究中, 沉积物粒度结果为重建古环境变化提供重要参考, 本文研究认为在普里兹湾海域沉积物粒度研究中去除生物硅对研究结果有积极作用。

Influence of biogenic silica on measurements of sediment grain size in Prydz Bay,Antarctica

Samples obtained from a gravity core from Prydz Bay were pretreated by the removal of biogenic silica. Sediment grain size and volume percentages of particles of different sizes were measured; results between treated and untreated samples were compared. Main grain size distribution of biogenic silica in the sediments of Prydz Bay is <3Φ, 5.25—7.25Φ, and 8.75—9.75Φ. We conducted a correlation analysis on the grain size parameters and the percentage content of each component obtained from the two sets of experiments, and inferred that biogenic silica has little influence on the average particle size, sand, silt and clay fractions in the sediment, but has a clear influence on the sorting, skewness and kurtosis of grain size distribution; as a result, in untreated samples, measured particle size is larger than actual particle size. Study results indicate that removal of biogenic silica from sediments is a prerequisite for grain size studies and provenance analyses in polar regions.