渤海湾百年来沉积物Li/Ba和Rb/Sr协同变化的地球化学特征与环境指示作用  

Geochemical covariation characteristics of Li/Ba and Rb/Sr and their environmental indication in recent hundred years of the Bohai Bay

作　　者：宋金明[1] 徐亚岩[2] 段丽琴[1] 

机构地区：[1]中国科学院海洋研究所,山东青岛266071 [2]中国水产科学研究院东海水产研究所,上海200090

出　　处：《海洋科学》2014年第1期79-84,共6页Marine Sciences

基　　金：国家自然科学基金资助项目(41306070)

摘　　要：通过对渤海湾两根柱状沉积物中Li、Rb、Sr、Ba以及Li／Ba和Rb／Sr的系统研究。阐明了百年来沉积物中Li、Rb、Sr、Ba的垂直变化特征，发现了在不同年代沉积物中Li／Ba和Rb／Sr具有的协同变化规律，揭示了沉积物Li／Ba和Rb／Sr作为近海区域性环境演变可能的指示作用。结果表明。在0～20cm沉积层间，Li、Rb在A2和A6柱中均有随深度增加而增加的趋势，Sr和Ba随着深度的增加而降低：近百年来，渤海湾沉积物A2和A6柱中Li／Ba和Rb／Sr垂直变化表现出惊人的协同变化特征，Li／Ba和Rb／Sr在近河口的A2柱中，基本呈现随深度的增加而增加的趋势，而在远离河口区域的A6柱中．其结果是0-15cm段（1963-2008年），Li／Ba和Rb／Sr随深度的增加而增加，15cm以下（1900～1963年）则基本稳定，在海洋过程作用下该区域沉积物Li／Ba和Rb／Sr变化发生在45a时间段内：沉积物中Li／Ba反映沉积物从河流进入海湾沉积过程中的变化，Rb／Sr反映来源沉积物的化学风化历史并指示来源区的气候环境变迁过程。A2沉积柱的20～22cm（20世纪30年代）和10～12cm（20世纪60年代），Li／Ba出现极小值，与1939年和1963年的海河流域大洪水相契合，在0～12cm段，两柱样Rb／Sr随着深度的降低有明显减小的趋势，对应20世纪70年代初至2008年这一区域百年来气温升高并持续高温的时段。Based on the researches on Li, Rb, Sr and Ba concentrations and Li/Ba and Rb/Sr in two sediment cores of theBohai Bay, the vertical variations of Li, Rb, Sr and Ba concentrations in recent hundred years were studied, the covariation patterns of Li/Ba and Rb/Sr were found, and the environmental change indications of Li/Ba and Rb/Sr to the coastal waters were revealed in this paper. The results suggested that the Li and Rb concentrations increased with depth during 0-20 m in core A2 and A6, whereas the Sr and Ba concentrations decreased with depth. Surprisedly, the vertical distributions of Li/Ba and Rb/Sr displayed covariation characteristic in recent one hundred years, that was, Li/Ba and Rb/Sr increased with depth in core A2 near the Haihe Estuary whereas those in core A6 off the estuary increased with depth during 0-15 cm （corresponding to 1963-2008 years） and then remained stable below 15 cm （corresponding to 1900-1963 years）. In conclusion, the changes of Li/Ba and Rb/Sr affected by marine processes mainly occurred in recent 45 years. Li/Ba mainly reflected the deposition process change of riverine sediments entering the Bohai Bay; however, Rb/Sr dominantly reflected the chemical weathering history of original sediments and indicated climate change of source region In core A2, the minimum value of Li/Ba appeared in 20-22 cm （corresponding to 1930s） and 10-20 cm （corresponding to 1960s）, according with the floods of the Haihe River in the years of 1939 and 1963. Rb/Sr decreased with depth during 0-12 cm in both cores, according with the temperature increase during early-1970s to 2008.

关 键 词：LI Ba和Rb Sr 环境变化指示 柱状沉积物 渤海湾 

分 类 号：P731[天文地球—海洋科学]