青藏高原东缘黄土石英光释光信号积分区间选择  

Selection of integration time intervals for quartz optically stimulated luminescene(OSL) of loess in the eastern Tibetan Plateau

作　　者：刘楠楠 杨胜利[1] 刘维明[2] 成婷 陈慧 唐国乾 李帅 梁敏豪 LIU Nannan;YANG Shengli;LIU Weiming;CHENG Ting;CHEN Hui;TANG Guoqian;LI Shuai;LIANG Minhao(Key Laboratory of Western China’s Environmental Systems(Ministry of Education),College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China;CAS Key Laboratory of Mountain Hazards and Surface Process,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China)

机构地区：[1]兰州大学资源环境学院西部环境教育部重点实验室,兰州730000 [2]中国科学院水利部成都山地灾害与环境研究所山地灾害与地表过程重点实验室,成都610041

出　　处：《地球环境学报》2018年第6期569-579,共11页Journal of Earth Environment

基　　金：国家自然科学基金项目(41472147);兰州大学中央高校基本科研业务费专项资金(lzujbky-2017-ct05;lzujbky-2015-k10);兰州大学西部环境教育部重点实验室开放基金~~

摘　　要：光释光信号积分区间的选择对等效剂量(De)的估算有重要影响。光释光衰减曲线并非单一的指数衰减,而由多个指数衰减函数组成,且每个衰减函数代表不同的信号组分。因矿物晶格陷阱类型不同,各组分有不同的衰减率、热稳定性等。本文对采自青藏高原东缘4个典型黄土分布区的黄土样品进行了系统的石英光释光组分分析和背景区间扣除研究。结果发现:(1)高原东缘黄土石英光释光信号由快、中、慢组分组成,并以快组分占主导,适合用单片再生剂量法测定等效剂量;(2)不同背景区间扣除对小于10 Gy样品等效剂量结果影响较小,误差范围内一致;(3)对大于10 Gy样品,选取早、晚不同背景区间扣除其等效剂量结果差异显著,两者差值占晚期背景扣除所得De值的10%—38%,且有随De值增加而增大的趋势,因此计算大于10 Gy样品De时应慎重选择积分区间。Background,aim,and scope Selections of the integration time intervals for the quartz OSL is very important for estimating equivalent dose(De).The traditional method,in calculating De,is to select the first few seconds of OSL decay curve as the initial interval and subtract the last few seconds of decay curve as the background subtraction(e.g.0-0.4 s,19.9-24.9 s).In 2010,Cunningham and Wallinga suggested that the early background subtraction should be used in standard protocol.That is to select the first few seconds of OSL decay curve as the initial interval and subtract its followed few seconds interval as the background subtraction(e.g.0-0.4 s,0.4-1.4 s).Some recent studies also indicated the differences exist between De values by using‘early background’and‘late background’.To further illustrate the effect of different background interval subtractions on the equivalent dose,we have systematically studied loess samples collected from the four typical loess distribution areas in the eastern margin of the Tibetan Plateau.Materials and methods OSL samples were collected from 4 typical loess profiles using steel pipes,~25 cm long and^4 cm in diameter.Extraction of the quartz from samples and the OSL measurements were performed in the red light darkroom in the OSL laboratory of Chengdu Institute of Mountain Hazards and Environment,Chinese Academy of Sciences.First,the outside parts of sample,about 3-5 cm,were removed.After that,the 10%HCl and 30%H2O2 were added in the residual samples to remove carbonates and organics.Next,the 38-63μm of quartz components was extracted for measuring De.After De of all samples were measured with the single aliquot regenerative-dose(SAR),we analyzed the components of quartz OSL signals of all samples and selection of integration time intervals using Analyst 4.53.Results The proportions of fast component of all samples are above 84%.For those samples of<10 Gy,the difference of average De between A1(0-0.4 s,0.4-1.4 s) and A2(0-0.4 s,19.9-24.9 s)is only 0-0.32 Gy,which is 0-5% for

关 键 词：光释光信号组分 背景扣除 石英光释光 黄土 青藏高原 

分 类 号：P597.3[天文地球—地球化学]