南海甘泉岛海鸟粪土沉积层元素地球化学特征及生态环境意义

n ornithogenic sediment profile (namely GQ) are well preserved in Ganquan Island, South China Sea. Based on concentrations of different geochemical indices for the 107 sub-samples, we analyzed geochemical characteristics of the profile. It is shown that concentrations of organic matter and some elements in the upper 11cm are very different from that of samples below the depth 11cm. There is a significant correlation between TOC and phosphorus below the depth 11cm, suggesting the input of guano into the sediments, while correlation between TOC and phosphorus is weak for the samples above 11cm, indicating that plant residue played an import role in determining the chemical composition for the relative young samples. Such abrupt change is very likely the evidence of pedogenesis' strengthening for Ganquan Island in history. It is also shown that the elements Cu, Zn, Cd, P, Ba, As and Se are bioelements, which would be ideal indicators of guano input. Compared to our previous study on Dongdao Island, South China Sea, we conclud that except for the element Ba, combination of the other six elements is a proxy for seabird population on Xisha Islands, South China Sea, and organic matters determines concentrations of Fe2O3, Al, K2O, Mn and Ti in the sediment profile. With Q-mode factor analysis on the total 16 inorganic elements, we found that source materials (guano, coral and humus) were probably key factors that determined geochemical characteristics of GQ profile.