湘江悬浮物的稀土元素地球化学研究

Geochemistry of Rare Earth Elements in the Suspended Particulate Matters of Xiangjiang River

在湘江及其支流采集了44件悬浮物样品进行稀土元素ICP—MS分析。研究表明,湘江悬浮物中稀土总量(∑REE)、轻稀土(LREE)和重稀土(HREE)含量分别为63～387μg/g,58.2～353μg/g和4.8～34μg/g。尽管湘江悬浮物中稀土分布不均匀,稀土含量相差很大,所有样品的球粒陨石标准化曲线均呈向右倾斜的富LREE的模式,北美页岩标准化模式为LREE稍富集的平坦型。湘江中下游河心与两岸水体悬浮物中稀土发生了明显分异。湘江悬浮颗粒物中REE受多方面因素控制,其源区控制了REE分配模式,而其稀土元素含量与颗粒中粘土矿物及重矿物有关。支流捞刀河悬浮物稀土的分布模式为Eu正异常型,与北美页岩有显著差别,捞刀河的悬浮物物源及成因有待进一步研究。

Forty-four sediment samples were collected from the Xiangjiang River and its tributary, and its REE concentrations were analyzed using Inductively Coupled Plasma-Mass Spectrometry （ICP-MS）. The total REE concentration （∑REE）, light-REE （LREE） and heavy-REE concentration （HREE） were 63 - 387,58.2 - 353 and 4.8 - 34 mg·kg^-1, respectively. In spite of district differences in REE concentrations, the cbondrite-normalized REE patterns are characterized by LREE-rich right curves in the suspended matter of all samples. The REE curve normalized by North America shales（NASC） is a horizontal one. REE in suspended matter of Xiangjiang River are controlled by many kinds of factors, probably associated with clay minerals and heavy minerals. The chondrite-normalized REE patterns in suspended matter of Laodao river displayed positive Eu anomaly, which is distinctly different from North America shales, and its sources and origin need to be further studied in the future.