XRF岩心扫描估算海洋沉积物有机碳含量的适用性

The estimation of organic contents in marine sediments based on bromine intensity by the XRF scanner

X射线荧光光谱仪(XRF)的沉积物岩芯扫描技术可以无损、快速获得高分辨率的溴(Br)计数信息,可用来估算海洋沉积物中有机碳含量,但是其准确性及各种校正方法的效果还需要深入研究。文章选择两根在有机质来源构成上有明显差异的阿拉伯海和南海的沉积柱,系统开展了沉积物有机碳(total organic carbon,TOC)含量与Br计数的相关性分析,深入剖析了沉积物含水量、Br计数校正方法等对利用Br计数估算沉积物TOC含量的影响及评估该方法的适用性。对于有机质含量较高的海洋沉积物而言,Br计数与TOC含量之间存在较好的相关性,且其相关性与是否校正Br计数没有显著关系。在陆源有机质输入量比较大的沉积物样品中,则需谨慎采用Br计数来估算沉积物的总有机碳含量。

The Bromine(Br)intensity collected by the non-destructive X-ray fluorescence(XRF)core scanner has been used to estimate the content of organic carbon in marine sediment in high speeds.However,the accuracy of this estimation and the effectiveness of various calibration methods need to be carefully evaluated.In this study,two gravity cores from the Arabian Sea and South China Sea,where the organic contents and their source components are different in sediment,are selected to investigate the correlation between the total organic carbon(TOC)content and the Br intensity by the core scanner.This study also analyzes the influence of water content and evaluates the effectiveness of different calibration methods used to estimate the TOC content according to the Br intensity.A good correlation is found between the Br intensity and the TOC in marine sediment with high organic carbon contents,no matter whether the Br intensity is calibrated or not.However,the estimation of sedimentary TOC content should be cautiously used when terrigenous organic matter is high.