Geochronology using Nucleogenic Neon

使用核生成氖进行地质年代学

基本信息

批准号：
1144500
负责人：
Kenneth Farley
金额：
$ 30.27万
依托单位：
California Institute of Technology
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2012
资助国家：
美国
起止时间：
2012-02-01 至 2015-01-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1144500&HistoricalAwards=false
关键词：
Geochronology using Nucleogenic Neon

项目摘要

This project will support the development of a new method for determining the formation ages of minerals, especially those that cannot currently be dated with existing techniques. The method is based on the ingrowth of a rare isotope of neon - 21Ne - from the decay of uranium and thorium. This technique should be especially useful for dating of iron oxide minerals such as hematite and magnetite, and will likely be applicable to understanding the timing and origin of economically significant ore deposits produced by both sedimentary and hydrothermal processes.Several important aspects of this dating system will be investigated. First, a set of experiments will be performed to determine the nuclear cross sections for the reaction 18O(&#945;, n) 21Ne, which produces the daughter isotope. These experiments will involve implantation of a known dose of &#945; particles of known energies into various target materials, followed by direct measurement of the 21Ne produced by isotope dilution mass spectrometry. Additional experiments will caharcterize the diffusivity of neon in likely minerals to be dated, which will establish under what temperature conditions neon retention is to be expected. Such data are necessary for accurate interpretation of the measured ages. A final set of experiments will be designed to identify the typical levels of uranium and thorium, as well as non-radiogenic neon, in minerals of interest for dating. These data will provide insight to what types of minerals are promising targets for the dating method.

该项目将支持开发一种新方法，以确定矿物质的形成年龄，尤其是那些目前无法使用现有技术的矿物质。该方法基于铀和th的衰减中霓虹灯21Ne的罕见同位素的生长。该技术对于赤铁矿和磁铁矿等氧化铁矿物质的约会特别有用，并且可能适用于理解由沉积和热液过程产生的具有经济意义的矿床的时间和起源。将研究该约会系统的重要方面。首先，将进行一组实验，以确定反应18o（＆＃945; n）21ne的核横截面，该截面产生子女同位素。这些实验将涉及植入已知剂量的＆＃945;已知能量的颗粒成各种目标材料，然后直接测量同位素稀释质谱法产生的21NE。其他实验将使可能过时的矿物质中霓虹灯的扩散率降低，这将在哪些温度条件下可以预期保留霓虹灯。这样的数据对于准确解释测得的年龄是必要的。将设计一组最终的实验，以识别在感兴趣的约会矿物质中典型的铀和th和非放射原性的霓虹灯。这些数据将提供有关哪些类型的矿物的约会方法有希望的目标。