石英标准生长曲线在青藏高原东缘黄土光释光测年中的应用  

APPLICATION OF QUARTZ OSL STANDARDIZED GROWTH CURVE FOR De DETERMINATION IN LOESS ON THE EASTERN TIBETAN PLATEAU

作　　者：李冬雪 刘楠楠 杨胜利[1] 刘维明 成婷 刘丽 罗元龙 LI Dongxue;LIU Nannan;YANG Shengli;LIU Weiming;CHENG Ting;LIU Li;LUO Yuanlong(Key Laboratory of Western China's Environmental Systems,Ministry of Education,College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,Gansu;Henan Key Laboratory of Research for Central Plains Ancient Ceramics,Pingdingshan University,Pingdingshan 467000,Henan;CAS Key Laboratory of Mountain Hazards and Surface Process,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,Sichuan)

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,甘肃兰州730000 [2]平顶山学院河南省中原古陶瓷研究重点实验室,河南平顶山467000 [3]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,四川成都610041

出　　处：《第四纪研究》2021年第1期111-122,共12页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:41877447和41472147);科技部第二次青藏高原综合考察研究项目(批准号:2019QZKK0602)共同资助。

摘　　要：石英标准生长曲线(SGC)法在黄土高分辨率光释光定年中有大幅节省测试时间的潜力,然而目前对该方法在不同时空尺度上的适用性尚存在争议。本文选取青藏高原东缘的典型黄土样品,通过系统地分析石英光释光生长曲线特征,检验SGC法和最小二乘法标准化生长曲线(LS-SGC)法在高原东缘黄土光释光定年中的适用性,结果显示:1)高原东缘黄土石英光释光信号以快组分为主,且同一地点不同样品、不同测片的生长曲线形态相似;2)当等效剂量(De)小于100 Gy时,不同地点样品石英生长曲线形态一致;大于100 Gy时生长曲线则具有不同的剂量响应特征;3)通过SGC法获得的De仅在0~100 Gy与实测值一致;LS-SGC法拟合的生长曲线结果更佳,并且LS-SGC法计算的De在100~200 Gy与实测De仍具有较好的一致性。研究结果有助于深入研究高原黄土光释光测年和风成沉积过程,同时也可为其他区域建立石英光释光标准生长曲线提供借鉴。The quartz OSL standardized growth curve(SGC)method has the potential to greatly save laboratory time in high-resolution dating for loess sequences.However,there is still controversial about its applicability on different temporal and spatial scales.In this study,we selected two typical loess sections at Maerkang(31°54’40.84″N,102°11’44.34″E;2666 m a.s.l.)and Zhouqü(33°46’44.4″N,104°23’56.4″E;2047 m a.s.l.)in the eastern Tibetan Plateau.The thicknesses of the two loess profiles are 5.1 m and 12 m,respectively.5 OSL dating samples were collected from each location.The characteristics of quartz OSL growth curve were systematically analyzed to examine the applicability of the SGC method and least square normalized growth curve(LS-SGC)method for determining the equivalent dose(De)of quartz grains from the loess in the study region.Our results show that:(1)The quartz OSL signals of the loess at the eastern Tibetan Plateau are dominated by the fast component,which are suitable for Demeasurement by single aliquot regenerative dose(SAR)method.The growth curve shapes of different samples and different aliquots indicated that a common quartz OSL growth curve exists in the study region.The quartz growth curves of different samples from Zhouqüand Markang were consistent within 100 Gy,and distinct deviations in the SGC curves were observed over 100 Gy for different sections.The SGC fitting curves of Zhouqü,Markang and total samples showed different growing trends;(2)The comparison of the Des determined by SGC,LS-SGC and SAR protocol showed that the LS-SGC method could get better results than the SGC method,with smaller residual sum of squares and less errors.The Des obtained by the two methods for the same sample was in good agreement with the SAR Devalues.The Devalues obtained by the central age model and the minimum age model indicated that the Des determined by SGC,LS-SGC and SAR methods for each sample were consistent within the 10%error;(3)For all loess samples,the Dedetermined by SGC and LS-SGC ag

关 键 词：光释光定年 标准生长曲线 最小二乘法 青藏高原 黄土 石英 

分 类 号：P534.63[天文地球—第四纪地质学] P597.3[天文地球—古生物学与地层学]