摘要
Manganese nodules are deposit rich in manganese and other metals which "grow" on the ocean floor. The study of manganese nodule growth rate and deep sea sediment has both scientific and economic significance. Natural <sup>10</sup>Be （half-life= 1.5 Ma ）is produced from spallations of atmospheric nitrogen and oxygen induced by cosmic ray in the stratosphere. After several years of residence in the atmosphere, the <sup>10</sup>Be falls on the earth or deposits in the ocean, accumulating in marine
