【摘要】 本文介绍了用轴系年代法中²³⁰Th_（过剩）和²³⁰Th_（过剩）/₂₃₂Th方法对取自太平洋海底的三个锰结核的生长速率及在海底的运动情况进行了研究。根据锰结核顶面和底面的²³⁰Th_（过剩）及²¹⁰Th_（过剩）²³²T_h的剖面,得出了三个锰结核的生长速率在1—10mm/M·Yr左右。另根据结核顶、底两面中²³⁰Th_（过剩）及²¹⁰Pb放射性印度的差异,可推算出锰结核在海底的翻滚周期在150<T<2.5×105年之间。更多还原

【Abstract】 Many research items on the manganese nodules from ocean bottom have been earned ouu but the growth rales of manganese nodules as well as their movements on the ocean bottom still puzzles the scientists. Various methods have bee created to answer these question. The trustworthy and acceptable methods are -230Th excess; -230Th / -232Th; -231Pa; K / Ar and -10Be.Three manganese nodules have been analysed using -230Th excess and -230Th / -232Th methods in order to detect their growth rates. The procedures are as follows: Successive layers of specimens from top side and bottom side arc scraped; acid leaching; separation and purification of U and Th using Dowcsi-8 resin; TTA extraction and a counting. The growth rates of three nodules using two different methods a;e agreeable, ranging l-10mm / M.Yr.The last turnover of the noduics can be evaluated from the different activities of -230Th at the surface of top and bottom sides. The results range from 5 ×10~4to 2.5 × 10~5ycars, thereat -210Pb profiles indicates that the turnover of the noduics didn ’ t take place in the last 150 years.更多还原