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宇宙成因核素埋藏年龄法是继宇宙成因核素暴露年龄法之后发展起来的又一同位素定年法,这一方法主要应用于沉积物定年。宇宙成因核素埋藏年龄法的原理是:具有不同半衰期的成对宇宙成因核素浓度及比值会随时间而发生变化,这些变化可以表示成时间的函数。因此,通过测定石英中成对宇宙成因核素的含量,可以定量化沉积物的沉积时间。宇宙成因核素埋藏年龄法在实际应用中还存在几方面不确定性:测量误差、参数引入的误差以及与地质模型的差异所引入的误差,本文对这些不确定因素进行了讨论。在实际采样过程中,应注意采样点及地质背景尽可能符合地质模型;在样品处理过程中,应保证石英纯度以及选用~(10)Be含量尽可能低的铍载体。在最后,本文例举了宇宙成因核素埋藏年龄法在昔格达湖相沉积和大邑砾岩定年中的应用,以及~(26)Al-~(10)Be-~(21)Ne联合定年。可以期待,这一方法在中国将被广泛地用于研究大型河流演化、中国早期人类的演化历史、第四纪早期冰川发育以及与青藏高原演化相关的构造和沉积问题。
The burial age of cosmic nuclide age method is another isotopic dating method developed after the exposure age method of cosmic nuclide, which is mainly applied to sediment dating. The principle of burial age of cosmic genetics nuclides is that the concentration and ratio of cosmotropic nuclides with different half-lives change over time and these changes can be expressed as a function of time. Therefore, by measuring the content of paired cosmogenic nuclides in quartz, sediment deposition time can be quantified. There are still several uncertainties in the burial age method of cosmic genetic nuclide in practice: the measurement error, the error introduced by parameters and the error introduced by the difference with the geological model. These uncertain factors are discussed in this paper. In the actual sampling process, attention should be paid to the sampling points and geological background as far as possible consistent with the geological model; in the sample processing, should ensure the purity of quartz and the selection of ~ (10) Be content as low as possible beryllium carrier. In the end, this paper illustrates the application of burial age of cosmic genetic nuclides in the deposition of the Xigeda lacustrine facies and the dating of the Dayi conglomerate, and the combination of ~ (26) Al- ~ (10) Be- ~ (21) Ne A year. It is expected that this method will be widely used in China to study the evolution of large rivers, the evolutionary history of early Chinese humans, glacial development in the early Quaternary, and the tectonic and sedimentary issues associated with the evolution of the Tibetan Plateau.