【作者】 杨传成；

【导师】 陈杰；

【作者基本信息】 中国地震局地质研究所 ， 地球化学， 2007， 硕士

【摘要】 近年来，光释光测年无论是在测量方法(单测片技术，Murray and Wintle，2000；简单多片再生法，王旭龙，2005a)还是测量仪器(Bφtter-Jensen，1999)方面都有较大改进，关于各种沉积环境年轻沉积物的研究被广泛报道(Stokes and Rhodes，1989；Ollerhead，1994；Berger，1995；Duller，1996；Stokes，2001；Jain，2004)。不同类型年轻沉积物样品的光释光测年本身尚有许多未解决的问题，光释光信号会受到诸多因素(如部分晒退、热转移等)的影响。本论文主要选择不同沉积类型的若干现代样品开展了大量的实验研究，以探寻年轻沉积物测年有效可靠的实验方法和技术流程，初步获得如下认识：1)利用细颗粒石英对Daybreak 1100型自动TL／OSL测量仪进行了标定，主要包括：K时间Beta辐照对邻近测样的影响，在0号位置辐照5000秒对毗邻的1号位置影响为2.45％，2号位置影响为0.024％，3号位置的影响则仅有0.013％，4～10号位置基本无影响；机载Beta源辐照时抬升臂3个不同位置(H、L、T3个位置)的辐照剂量率分别为0.0533±0.0013Gy／s、0.02928±0.0012Gy／s、0.01481±0.0012Gy／s。用本实验室Daybreak 2200型测量仪获得细颗粒石英的最小等效剂量为0.02±0.004Gy，假定环境剂量率为3Gy／ka，则其释光年龄约为7年。2)借鉴Duller(2003)提出的几种检验粗颗粒石英的方法，我们利用样品光释光信号衰减曲线、热释光发光曲线以及红外后蓝光激发与直接蓝光激发两者之比即红外逐出比率，判断释光信号的矿物来源，初步建立了细颗粒石英纯度的检验方法。3)对2006年4月16口北京降尘样品的实验研究表明，其IRSL信号极弱，[post-IR]OSL信号较强且有可能有长石的贡献。不同粒组石英的SAR法等效剂量变化于-1.27-18.86Gy之间，每个样品的等效剂量值均呈明显的不对称分布，推测可能与样品部分晒退、颗粒来源、实验测量方法流程等因素有关。对比不同前处理流程获得的[post-IR]OSL等效剂量值及其释光信号衰减曲线，原样中有可能含有部分在阳光下较难以晒退的颗粒，从而导致样品中颗粒在沉积前没有完全退零。不同前处理流程对样品IRSL信号感量变化影响不是很明显，对[post-IR]OSL信号感量变化影响较为显著。4)通过对不同气候条件、不同水动力环境若干现代水下沉积物的实验研究表明，不同粒组石英的等效剂量变化于0.17-28Gy，每个样品的等效剂量值均呈明显的不对称分布，存在明显的光晒退不彻底现象。总体而言，从上游到下游，随着搬运距离增加，石英样品等效剂量值总体呈现递减趋势，即其光晒退程度渐增。对比同一样品不同粒组石英的等效剂量，情况较复杂，在小冲沟沉积环境中，不论是气候湿润区还是干旱地区，可能由于搬运距离较短，石英样品(如LEDL07-165、166、259)的等效剂量值随粒径增大而变大，即细颗粒石英有可能比粗颗粒更容易晒退；对于帕米尔高原盖孜河的石英样品LEDL05-315，由于水动力较强，水流较急且水体较混浊，等效剂量值随粒径增大而变小，即粗颗粒石英较细颗粒更容易晒退。更多还原

【Abstract】 Over the last few years luminescence dating has been improved considerably, both in the methods for the estimation of the equivalent dose, De (with the development of the single-aliquot regenerative-dose (SAR) protocol, Murray and Wintle, 2000 and MSAR protocol, Wang et. al., 2005a) and in the measurement facilities (B(?)tter-Jensen and Murray, 1999). Dating of young samples from a wide range of depositional environments were widely reported (Stokes and Rhodes, 1989 Ollerhead, 1994 Berger, 1995 Duller. 1996, Stokes, 2001; Jain, 2004). However, the dating of young samples is inherently problematic, as a relatively greater proportion of the natural signal can be affected by several complicated factors (e.g. partial bleaching, thermal transfer, etc.), which may lead to inaccurate De estimation.The main purpose of this work is to choose the modern sediments, considering partial bleaching of affecting optical luminescence signal carry out a preliminary experimental study, to find effective and reliable methods and process technology for dating young sediments.The used samples for luminescence dating are from depositional environment of modern sediments the conclusions are as follows:It is important to confirm and quantify the occurrence of all systematic errors in luminescence analyses. First laboratory equipment is quantitativly estimate of the measurement performance. Calibrating of Daybreak 1100 automatic TL / OSL measurement instrument is carried out by fine quartz to examine and quantify the effects of cross-irradiation beta source irradiation uplift arm uplifting three different locations of the radiation dose. Dose is added to the annealing fine quartz sample for a short-bleaching step through the initial dose to resume exploring Daybreak2200 type of measurement and analysis ceiling was 0.02±0.0005Gy dose. It is assumed that environmental samples dose rate is 3Gy/ka, the equipment can detect the minimum age of 7 years.On Beijing dust samples of the April 16, 2006, using SAR measurements of quartz minerals, it is found that the equivalent dose distribution is asymmetric. Possibly it is related with partial bleaching and the particle source, experimental measurement of the flow and other factors. When the samples using different pre-treatment process to get the equivalent dose values, the results show that the originals may contain some sun bleaching retreat to the material, or to the quartz feldspar mineral an outer membrane, resulting in sample particle deposition in the former have not been fully solved retreat; of different pre-treatment process samples.The work uses single-use film renewable France to observe the process of measuring the changes of the flu, The results show when using different pre-treatment process of dating luminescence signal change of the impact is not obvious. It is [post-IR] OSL flu luminescence signal changes affected more significantly.In Liangshan region of humid climate three modern samples are,collected. In the arid weather aera four modern samples in gully are collected and three modern sample in the Gez River bed .The results showed that upstream samples equivalent dose is far higher than the downstream sample, In such an environment downstream samples should be collecting preferently; by comparisons of its different size dose equivalent value, in a small gully sedimentary environment, regardless of region humid climate or arid areas, fine-grain may be more easily bleaching than coarse grain. The three samples of Gez River equivalent dose value increases with the size reduction, possibly due to poor vegetation cover, and very rapid the water flow. Coarse grain sample is sufficiently has bright and a greater probability than fine particles.Modern slope wash samples LEDL06 - 489 fine grain component measurement, The results show that fine-grain mixed minerals us ing SAR has more problems,for fine-grain quartz components used SAR measurements, by a variety of analysis methods the equivalent dose is about 0.17 Gy, Afterd the sample environment dose rate value is obtained , the sample has the approximate age of about 80yr. According to the results of the sample.It is Afterd the sample environment dose rate value is obtained, the sample has the approximate age of about 80yr. According to the results of the sample.It is suggested that for this type of sediment fine quartz is choosen to measured dose equivalent value.更多还原