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:研究了东太平洋多金属结核中 U、Th同位素的深度分布与生长速率 .结果表明 ,东太平洋多金属结核中的 2 3 4U/ 2 3 8U) A.R.与海水接近 ,证实了 U的海水来源 ;2 3 4U及 2 3 8U的活度并不随深度增加而减小 ,而是在次表层和更深层出现极大值 .2 36 7站结核中 2 3 2 Th的活度在次表层有最大值 ,之后随深度的增加而降低 ,反映了结核生长过程中成岩作用的影响 ;1797站南结核中 2 3 2 Th表层有最大值 ,其它各层的变化较小 ,说明成岩作用对它的影响较小 .结核中存在大量过剩的 2 3 0 Th,并随深度呈指数衰减 ,根据 2 3 0 Thex法及 2 3 0 Thex/ 2 3 2 Th法求出东太平洋多金属结核的生长速率为 5.6 4～ 7.12 m m/Ma.
: The depth and growth rates of U and Th isotopes in the polymetallic nodules of the eastern Pacific Ocean were studied.The results showed that the 23 4U / 2 3 8U AR in the eastern Pacific polymetallic nodules was close to the seawater, confirming the seawater source of U; The activities of 2 3 4U and 2 3 8U did not decrease with the increase of depth, but the maxima appeared in the subsurface and deeper layers.236 The activity of 2 3 2 Th in station 7 tuberculosis had the highest value in the subsurface , Then decreased with the increase of depth, reflecting the influence of diagenesis during the growth of tuberculosis. The maximum value of 2 3 2 Th surface in southern station of 1797 station and the change of other layers were small, indicating that diagenesis had more influence on it There was a large excess of 230 Th in tuberculosis and an exponential decay with depth. The growth rate of polymetallic nodules in the Eastern Pacific was calculated to be 5.6 4 according to the 230 method and the 23 0 Thex / 2 3 2 Th method ~ 7.12 mm / Ma.