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自然界中广泛分布着许多天然放射性同位素,它们主要的是铀系、铀-锕系和钍系元素,除母体~(238)U、~(232)Th和~(235)U外,还有一系列的不同半衰期的子体元素。研究它们的含量分布及运动规律是地球化学的重要内容。在这些元素中,有的可以用来测定地质的年龄,因而它是地质研究的重要工具。过去几十年,世界规模的氢弹、原子弹试验污染了大气。目前,除半衰期较短的同位素已衰变之外,还有一些半衰期较长的同位素仍然存在于地球界质
Many natural radioisotopes are widely distributed in nature. They are mainly uranium series, uranium-actinide series and thorium series. In addition to maternal 238 U, 232 Th and 235 U, Different half-life sub-body elements. Studying their content distribution and movement law is an important part of geochemistry. Among these elements, some can be used to determine the geological age, so it is an important tool for geological research. Over the past few decades, world-scale hydrogen bombs and atomic bomb tests polluted the atmosphere. At present, in addition to the decay of isotopes with shorter half-lives, some isotopes with longer half-lives still exist in the boundary of the Earth