摘要
￣（１３７）Ｃ及￣（２１０）Ｐｂ＿（ｅｘ）方法广泛应用于湖泊现代沉积计年。不扰动沉积物柱心的采样和高精度的分样装置是获取准确计年结果的前提。沉积物剖面中１９７５年层节￣（１３７）Ｃｓ次级峰值可作为辅助计年时标；沉积物中绝大部分￣（１３７）Ｃｓ处于稳定态保证了￣（１３７）Ｃｓ计年时标的可靠性。季节性滞水带缺氧湖泊中￣（２１０）Ｐｂ沉积后再迁移可能导致￣（２１０）Ｐｂ＿（ｅｘ）计年结果偏低。沉积物早期成岩过程中，铅化学相的转移提供了铅扩散迁移的地球化学条件；Ｐｂ－Ｐｏ的扩散机理分别受Ｆｅ－Ｍｎ循环控制。
The ￣(137)Cs and ￣(210)Pb_(ex) techniques are widely employed for dating recent sediments oflakes. There is important provision to gain dating results correctly with the sampling de-vice of no-disturbing sediments and the sample separation of high precision. The secondarypeak of￣(137)Cs in sediment horizon of 1975 could be as an assistant dating time marker. Mostpart of ￣(137)Cs in sediments is at stable position which provides reliability for ￣(137)Cs datingtime marker.The post-depositional remobilization of ￣(210)Pb could lead to the lower rate ofsediment accumulation in seasonal anoxic hypolimnia of lakes. The transformation of Pbspecies has provided the geochemical condition of its diffusion in the processes of early dia-genesis.The diffusion mechanism of Pb-Po is controlled by cycling Fe-Mn,respective-ly.
出处
《地球科学进展》
CAS
CSCD
1995年第2期188-192,共5页
Advances in Earth Science
基金
国家自然科学基金
