• 论文 •

### 福州盆地残留沼泽沉积的137Cs同位素定年与沉积环境演化

1. 1．中山大学 地球科学系，广州 510275；2．广东省地质过程与矿产资源探查重点实验室，广州 510275； 3．Department of Anthropology，University of Hawaii，Honolulu，USA
• 出版日期:2013-10-02 发布日期:2013-10-02
• 基金资助:
国家自然科学基金（41072128）；中山大学中央高校基本科研业务费专项资金（10lgzd08；11lgpy53）

### 137Cs Dating and Sedimentary Environment Evolution of a Residual Swamp in Fuzhou Basin

ZHANG Guifang，ZHENG Zhuo，BARRY Rollet，HUANG Kangyou，YUE Yuanfu，ZHU Guangqi

• Online:2013-10-02 Published:2013-10-02

Abstract: A 540 cm long sediment core was collected from a residual swamp in Fuzhou basin. Element geochemical, 137Cs and 14C isotopic dating techniques were applied to determine recent sedimentation rates. The results indicated that there were two sedimentary environments for the core. The sedimentary environment of the lower part was proluvial-alluvial and the upper part was swamp. However, both of them were very stable. The three concentrations of 137Cs from swamp sediment were in excellent agreement with the 137Cs fallout activities of the northern hemisphere. The interpolated age of the core bottom was 1950, agreeing with the dating result of 14C, suggesting the 137Cs dating result of this core was reliable. The sedimentation rates showed that the proluvial-alluvial sediment was very rapid in the subsiding area of Fuzhou Basin from early 1950s to middle 1960s which was about 20.9 cm/a. With the change of the basins and plains and the development of Channel Bars in the lower reaches of the Minjiang River, the broad channel changed to the swamp, and the sedimentation rate was decreasing: from middle 1960s to middle 1970s, it was about 9.9 cm/a; and from middle 1970s to middle 1980s, it was about 7.1 cm/a; and later, it was about 3.1 cm/a. The extremely large sedimentation rates in the study area were closely related to the different activities of fault blocks in Fuzhou Basin.