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基于热释光技术的沉积物标样制作和沉积物测年若干基础问题研究
【作者】 何友兵；
【作者基本信息】 首都师范大学 ， 第四纪地质学， 2011， 硕士
【摘要】 释光技术被扩展应用到各种需要进行年代测定领域,如早些时候的古物鉴定,及后来的地质学、空间科学、海洋学、第四纪研究等领域。同时也不可忽视释光基础研究是应用研究的前提。为此：1.制作标样L样和Y样,包括实验室前期处理,标样的均匀性检验、离群值检验和定值等。给热释光技术制作大质量的地质标样提供一套科学、实用的方法。2.选取L样,分析11～40μm、40～74μm、74～100μm、100～150μm不同粒径样品对热释光值的响应。实验结果显示：不同粒度具有相同剂量同一样品热释光值是不同的,因此测定时选取的粒度要一致且尽量限定在较小的范围内。3.选取L样,分析矿物质量对释光值的影响,结果显示：当质量<4 mg时,随样品质量增大,热释光强度也相应增大,且有良好的线性关系,可做质量归一；当质量为>6 mg时,随样品质量增加,热释光强度趋于不变,不可做质量归一4.选取L样品,分析比较矿物质量对剂量的响应情况,结果显示：不同质量的样品在检测面积一定的情况下,响应结果完全一致,在检测面积不同的条件下,释光量随剂量增长斜率不一致。5.选取Y样进行光晒退实验,表层样品释光值退去大约85%(不可晒退组分未考虑),样品积存热释光的晒退程度随着深度增加逐渐减小,到1000um左右的深度时无变化。6.针对于昌平钻孔样品,提取93.1m样石英颗粒,用40%HF按每克2ml溶蚀约80min,一般可获得较纯的石英颗粒,但溶蚀时间不宜过久,300min石英损失量过大,导致样品不适合进行TL测定；分析104m样附加剂量和释光量的关系,300Gy以下随着剂量的增长释光量呈一次线性增长,随后呈现非线性增长。对104m样而言,其天然释光量已处于非线性区,石英存在释光饱和现象。7.利用热释光技术对泥石流源区、流通区沉积物样品进行了等效剂量的测定,泥石流沉积物释光本底值依源区、流通区呈现降低趋势；对泥石流台地各层位不同性质沉积物样品退火程度进行比较,细粒样品比粗粒样品退火程度明显要大。本文认为台地中的泥块样是较为理想的年代测定载体,但泥石流物质的退火并不彻底,需要进行残留本底值的研究和矫正,相关的退火机制有待于进一步研究。
【Abstract】 Thermoluminescence technique is extended to the age determination of needs areas, such as early identification of antiquities, and later geology, oceanography, space science, Quaternary Research and other fields. However, TL is the application of basic research has always been an important prerequisite.1. Using of thermoluminescence technique produce the standard samples of L and Y, including the pre-processing laboratory, homogeneity test, outliers test and valuation of standard samples. The results provide a scientific, practical approach for producing massive geological standard samples with the luminescence method.2. Using the different diameter of L samples,11～40μm,40～74μm,74～100μm,100～150μm analyze the TL of them. The results that the different diameter of L samples with same doses is different, so the determination of particle size should be consistent and confined to a smaller range.3. Using the different quality of L samples analyze and compare the TL of them, the experimental results show that:when the quality of samples<4 mg, the TL increased with the quality accordingly, and there is good linear relationship between quality and TL for normalization.when the quality of samples> 6 mg, the TL does not tend to change, and there is not need to do the quality of normalization of the samples’TL and its quality.4. Using the different quality of L samples analyze and compare the dose response of them. the experimental results showed that:In the detection area of a certain case, the different quality samples of TL is same, and the does response exactly uniformly. Under the different detection area conditions, the amount of TL release different, and the slope that TL increased with the dose is inconsistency5. Using the different quality of Y samples do the experiment of light bleach test. TL values of surface samples receded about 85%(non-bleach component is not considered), the sample accumulated bleach TL level decreases with depth, and there is no change about the depth of 1000um.6. Using 93.1m samples of Changping drilling extract quartz, the experimental results showed that:2ml per gram samples with 40% HF dissolute about 80min, it can get the availability of pure quartz particles generally, but the dissolution time is not too long, and 300min is excessive loss of quartz, the treated samples are not suitable for TL measurement. Using 104m samples of Changping drilling that has extracted quartz analyze the interpretation of the relationship between its additional dose and TL. when its additional dose is less than 300Gy, the result release that there has a linear growth between the amount of TL and the dose, when its additional dose is more than 300Gy, the growth is nonlinear. For 104m sample, the amount of its natural TL that has been detected is in the nonlinear regions, and the 104m samples has reached the quartz saturation.7. The work tests the equivalent dose of the samples from source area and drainage area. It is proved that thermolμminescence dose decreased in order from source area to drainage area. The work compares to the amount TL of different layers of the debris flow sediment samples, it is showed that the annealing of nature thermolμminescence of fine-grained samples was larger than the coarse-grained samples. This paper argues that the mud-like platform is an ideal dating carrier. However the debris flow material annealing is not sufficient, it is need for correction of the background value and studying the mechanism of thermo-lμminescence attenuation.