Collaborative Research: Nuclear Studies of Continental Erosion Processes and Rates

这是一个实验项目的延续， 进一步发展和应用研究地球的核方法， 地表地质作用，包括大陆板块的研究 侵蚀 该技术是基于原位生产的 通过宇宙射线的核相互作用， 以来 宇宙辐射吸收平均自由程为-50厘米 岩石，以及由于原位核素，10 Be（半衰期，1.5 × 106年）， 26 Al（半衰期，0.7 × 106年）和14 C（半衰期，5730年）可以 在大多数岩石中很容易研究，人们可以最佳地表征 括号内的表面张力变化2X 10 -5- 6X 10 -3 cm.yr-1;较高 使用半衰期较短的核素可以获得较低的速率 (39Ar半衰期269年）和稳定核素3 He和21 Ne 分别 我们已经展示了 石英中原位10 Be和26 Al的研究方法 从大约50个岩石样本中提取的。 我们研究了他们的 生产率在石英在自然环境中， 用高能粒子照射石英。 而且我们有 研究了几个地区的地表侵蚀速率和暴露历史， 岩石，也确定了形成的时间的峡谷 亚利桑那州的暗黑陨石坑。 所进行的测量确定了 两年前我们向国家科学基金会提出的核方法的一部分。 我们现在 我建议继续我们的测量另一个时期2 充分开发和利用在 原位法 简单地说：我们将包括原位14 C的研究， 我们将获得关于同位素生产率的进一步数据; 我们将继续研究选定的 表面。 此外，我们提出了一套新的应用程序， 核方法，如研究断裂和全球历史 沙子。 现在已经实现了多种原位核素的使用 有可能彻底改变对表面的理解 开放了地球表面的绝大部分， 数字年龄控制。

This is a continuation of an experimental program to further develop and apply a nuclear method for studies of earth- surface geologic processes, including studies of continental erosion. The technique is based on in situ production of nuclides in rocks by nuclear interaction of cosmic rays. Since the absorption mean free path of cosmic radiation is - 50 cm in rocks, and since in situ nuclides, 10Be (half-life, 1.5X106 yrs), 26Al (half-life, 0.7X106 yrs) and 14C (half-life, 5730 yrs) can easily be studied in most rocks, one can optimally characterize surficial changes in the bracket 2X10-5-6X10-3 cm.yr-1; higher and lower rates are accessible using shorter half-life nuclides (39Ar, half-life 269 yrs) and stable nuclides, 3He and 21Ne respectively. We have already demonstrated the potential of the method based on studies of in situ 10Be and 26Al in quartz extracted from some 50 rock samples. We have studied their production rates in quartz in natural settings, and also by irradiating quartz with high energy particles. And we have studied surface erosion rates and exposure histories of several rocks, and also determined the time of formation of the Canyon Diablo meteorite crater in Arizona. The measurements carried out have established the potential of the nuclear method proposed 2 years ago by us to NSF. We now propose to continue our measurements for another period of 2 years to fully develop and to exploit the potentials of the in situ method. Briefly: we will include studies of in situ 14C in quartz; we will obtain further data on isotope production rates; we will continue studies of surficial erosional rates of selected surfaces. In addition, we proposal a set of new applications of the nuclear method, e.g. studying faulting and history of global sands. The use of multiple in situ nuclides has the now realized potential to revolutionize the understanding of surficial processes by opening up the vast majority of earth's surface to the numerical age control.