地震地质 ›› 2006, Vol. 28 ›› Issue (4): 668-674.

• 新技术应用 • 上一篇    下一篇

方解石脉ESR定年信号和测量条件的研究

贾丽1, 鲍继飞1,2, 尹功明1, 刘静伟1,2, 李建平1   

  1. 1. 中国地震局地质研究所地震动力学国家重点实验室, 北京, 100029;
    2. 中国地质大学, 北京, 100083
  • 收稿日期:2006-07-05 修回日期:2006-09-02 出版日期:2006-12-21 发布日期:2009-08-27
  • 作者简介:贾丽,女,1982年出生,2004年7月毕业于聊城大学资源环境与城市规划学院资源环境与城市规划专业.现在中国地震局地质研究所攻读硕士学位,研究方向为第四纪年代学,电话:010-62009138或010-62009097,E-mail:jiali8299@163.com.
  • 基金资助:
    国家自然科学基金(40572104);国家发展与改革委员会发改投资“城市活断层试验探测”项目(20041138)共同资助

STUDY ON ESR SIGNAL CENTERS AND MEASUREMENT CONDITIONS FOR DATING OF CALCITE

JIA Li1, BAO Ji-fei1,2, YIN Gong-ming1, LIU Jing-wei1,2, LI Jian-ping1   

  1. 1. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
    2. China University of Geosciences, Beijing 100083, China
  • Received:2006-07-05 Revised:2006-09-02 Online:2006-12-21 Published:2009-08-27

摘要: 方解石脉是与断裂构造相关并在基岩区断裂带中常见的物质.方解石脉的定年有时对研究基岩区断裂活动时代具有重要的意义.方解石脉ESR测年是目前采用的测年方法之一,但是对于方解石脉的ESR信号特征及其测量条件目前尚没有定论.文中研究样品采自云南洱海海东断裂带中.根据对样品的初步研究认为,方解石脉人工辐照时易产生不稳定的短寿命信号,在测量之前至少将其在室温条件下存放5d.天然方解石脉中一般具有多个ESR信号,其中g=2.004 0和g=2.002 3信号对吸收剂量具有良好的响应关系,可以用于测年.这两个信号的增长曲线表明至少在1 500Gy剂量范围内呈线性增长.人工给定已知剂量方法表明,要获得可靠的古剂量,g=2.004 0和g=2.002 3的信号所选择的微波功率是不同的.对于g=2.004 0信号,测量的微波功率应在0.8或2mW;而g=2.002 3信号,微波功率应选择2或5mW.

关键词: ESR, 方解石脉, 等效剂量, 定年信号, 测量条件

Abstract: Calcite is a common matter in the fault zone and it is often related with fault movement,so its dating is of vital significance for studying the time of fault movement.At present,ESR method is one of the ways for measuring the age of calcite,but there are no final conclusions regarding the ESR signals and measurement conditions of calcite.The samples used in this article were picked from the east of Erhai,Yunnan.According to the preliminary study of the samples,we found that calcite was liable to generate unstable short-lived signal when it was artificially exposed.So before measuring,the samples were kept under the room temperature condition for at least 5 days to eliminate the jamming signals.Generally,in natural calcite,there are many ESR signal centers,among them,the ones,g=2.0040 and g=2.0023,respond well to absorbed dose,and can be used in the dating.Growth curves of these two signals indicate a linear growth at least in the range of 1500Gy.But it is indicated with the artificially fixed known dose method that different microwave powers have to be taken for g=2.0040 and g=2.0023 signals.If we consider the deviation of ED value is smaller than 5%,then the microwave power should be 0.8 or 2mW for the g=2.0040 signal,and the microwave power be 2mW or 5mW for the g=2.0023 signal.

Key words: ESR, calcite, ED, dating signals, measurement conditions

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