摘要
本文阐述了^(210)Pb法的CF模式年龄计算原理,并用此模式计算了云南滇池沉积柱样的年龄。发现CF模式年龄与普通的CA模式年龄有明显的差异,而^(228)Th/^(232)Th法和^(239,240)Pu分布都表明CF模式年龄是可靠的。此年龄结果显示了近一百年来滇池的沉积通量是变化的。
210Pb geochronology has been widely applied to dating recent sediments in lakes, estuaries, and coastal marine environments. In this paper, the Constant Flux of Supply model (CF) has been applied to calculating the ages and sedimentation rates of two sediment cores from Dianchi Lake, Yunnan Province, in comparison with generally used Constant Activity model (CA). The CA and CF models have given quite different predictions of the ages of sediment sections for these two cores. Meanwhile, the results of 228Th/232Th method and 239,240Pu distribution are consistent with the CF age and show some difference from the CA age. The CF model indicates that the sedimentation rates of Dianchi Lake were variable during the past 100 years, ranging from 140 mg/cm2/a to 225 mg/cm2/a. It is likely that the longterm variation in sedimentation rate is due to both natural and artificial processes.
出处
《地球化学》
CAS
CSCD
北大核心
1990年第4期327-332,共6页
Geochimica
基金
国家自然科学基金
