碳酸盐含量对莱州湾南岸钻孔沉积物粒度测试结果的影响

Influences of Carbonate Contents on the Grain-size Measurements of Borehole Sediments From Southern Shore of Laizhou Bay

采用2种不同的前处理方法对莱州湾南岸钻孔沉积物样品进行粒度测量。通过比较沉积物粒度的粒级组成发现,未去除碳酸盐颗粒的测量结果,黏土粒级含量显著增加,粉砂粒级的变化主要受到黏土粒级含量增加的影响而降低,砂粒级未见明显的变化规律。应用2参数Weibull分布,对沉积物粒度分布进行拟合,发现测量样品的粒度分布以3峰态和4峰态为主,是否去除碳酸盐不改变粒度分布的基本形态,但对各组分的相对含量影响明显。通过实验对比,我们认为,粒度测量的前处理过程中去除碳酸盐是必要的。

Two pretreatment methods are respectively used to measure grain-sizes of borehole sediments from the southen shore of the Laizhou Bay.It is learnt from the comparison between the grain-size compo-sitions respectively from the two methods that clay content is significantly higher in the pretreated samples where the carbonate grains remain,silty sand content is lower since it is influenced by the higher clay con-tent,and sand content becomes less changable.Then the Weibull distribution function with its two pa-rameters are used to respectively fit the grain-size distributions,and it is learnt that there are almost two peaks or three peaks in the distributions,which keep unchangde whether the carbonate grains remain in the pretreated samples or not.Only the composition related to grain-sizes can be obviously influenced.It is believed from the experimental comparison that it is necessary to remove the carbonate grains from the pre-treated samples.