两种激光粒度仪测量湖泊沉积物粒度结果的对比

湖泊沉积物粒度参数是湖泊沉积与环境演变研究中常用的环境指标,近年来激光粒度仪的发展和广泛使用更是促进了粒度指标的应用并在很大程度上提高了精度和效率.然而不同的激光粒度仪对于同一样品的测量会得到不同的结果,本文利用两种常见的激光粒度仪测量了西藏纳木错的两支岩芯,并对结果进行了对比分析.从仪器的重现性来看,Mastersizer2000型激光粒度仪要优于LS13320型激光粒度仪,而LS13320型激光粒度仪在对含量较少的细颗粒和粗颗粒的检测效果上优于Mastersizer2000型激光粒度仪;两种仪器得到的粒度参数d(0.1)和d(0.5)无论在变化趋势还是绝对数值上都较为相似,而d(0.9)的差异则较大.对比研究结果为利用湖泊沉积物粒度参数提取古环境信息研究提供了基础依据.

Comparison of lake sediment grain size results measured by two laser diffraction particle size analyzers

Grain size parameters of lake sediments are common environmental proxies in lake sediment and environ- mental change study.With the development and widely use of laser diffraction particle size analyzer in recent years,the application of grain size proxies was advanced while the precision and efficiency of grain size measure- ment were also improved.However,the results of one sample may be having some difference by using different types of laser diffraction particle size analyzers.Here we report a case study of two lake sediment cores from Nam Co in Tibet using two familiar laser diffraction particle size analyzers.Seen from the repeatedly measurement results of the same sample,Mastersizer2000 manufactured by Malvern Instruments is better than LS13320 by Beckman Coulter,while LS13320 is better than Mastersizer2000 in the detective effect of relatively fine and coarse particles with rather few content.The grain size parameters d(0.1)and d(0.5)obtained by two instruments are rather sim- ilar in the variation trend as well as the absolute values,whereas the d(0.9)has rather big difference.The com- parative results of this study can provide base on extracting paleoenvironmental information by using grain size pa- rameters of lake sediments.