共查询到18条相似文献，搜索用时 250 毫秒
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提出了基于Ｘ射线激发的光释光测年原理，据此进行了初步实验研究。研究表明，利用Ｘ射线是可以激发辐射样品使其产生光释光信号的。 相似文献
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文章提出了利用Ｘ射线作光释光测年的激发光源，以此进行了实验研究，研究结果表明，利用Ｘ射线是可以激发辐射样品使其产生光释光信号的。 相似文献
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第四纪沉积物光释光测年中等效剂量测定方法的对比研究 总被引：12，自引：0，他引：12
准确地测定碎屑矿物沉积后吸收的等效剂量第四纪沉积物释光测年中最关键的一环。用光释光测年技术对几年全新世坡积物,古土地和黄土等样品中的石英,长石等碎屑矿物进行了测定等效剂量的对比研究。 相似文献
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甘肃玉门地区第四纪晚期构造阶地的红外释光测年 总被引：4，自引：0，他引：4
光释光（ＯＳＬ）测年是近几年从热释光（ＴＬ）测年基础工起来的测定第四纪沉积物年龄的一种新技术，其原理与ＴＬ测年类似。不同的是：ＯＳＬ是单色光束激发品体中储存的电离辐射能使其以光的形式释放出来。当用近红外线束作为激光光源时称之为红外释光测年。与ＴＬ测年相比，ＩＳＬ测年可以不考虑残留的ＯＳＬ信号，而且测量具有简便，迅速且准确等优点。本文用细颗粒红外释放技术对玉门地区的构造阶地进行了年龄测定，初步结果表 相似文献
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准确获得水成沉积物的年龄是第四纪年代学重要的前沿问题之一。随着释光技术的发展,水成沉积物释光测年在如下方面有新的进展:具体释光技术的选择、释光测量方法、测年矿物的种类、矿物的粒级和获得等效剂量的统计方法等。线性调整光释光技术能够提取光释光信号中衰退快的组分;单片再生法应用广泛;单颗粒技术在挑选沉积时晒退充分的颗粒方面具有一定的优势;水成沉积物中的石英比长石更易晒退;较多的实验表明水成沉积物中的粗颗粒比细颗粒更易晒退;获得等效剂量的统计模型很多,但尚无一种统计模型适用于所有样品。在此基础上探讨了水成沉积物释光测年在气候、构造运动、冰川进退历史和人类活动主导的土壤侵蚀量变化研究中的意义及今后的研究方向,为全面了解该领域的最新研究进展提供参考。 相似文献
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采用热释光和红外光释光测年技术获取了采自朝鲜半岛西南部和顺支石墓遗址剖面中的陶片和沉积物的年龄.古陶片的热释光年龄分别是(3100±210)a和(3680±320)a,相应文化层中支石墓墓葬层位的红外光释光年龄分别是(2200±190)a和(2900±310)a.古陶片的热释光年龄老于地层的红外光释光年龄,代表着支石墓... 相似文献
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释光技术在水成沉积物测年中的应用进展 总被引：1，自引：0，他引：1
准确获得水成沉积物的年龄是第四纪年代学重要的前沿问题之一。随着释光技术的发展,水成沉积物释光测年在如下方面有新的进展：具体释光技术的选择、释光测量方法、测年矿物的种类、矿物的粒级和获得等效剂量的统计方法等。线性调整光释光技术能够提取光释光信号中衰退快的组分;单片再生法应用广泛;单颗粒技术在挑选沉积时晒退充分的颗粒方面具有一定的优势;水成沉积物中的石英比长石更易晒退;较多的实验表明水成沉积物中的粗颗粒比细颗粒更易晒退;获得等效剂量的统计模型很多,但尚无一种统计模型适用于所有样品。在此基础上探讨了水成沉积物释光测年在气候、构造运动、冰川进退历史和人类活动主导的土壤侵蚀量变化研究中的意义及今后的研究方向,为全面了解该领域的最新研究进展提供参考。 相似文献
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浑善达克沙地的光释光测年研究 总被引：2，自引：2，他引：0
光释光测年技术以光可以使在半导体结晶固体中被俘获到光敏陷阱中的电子释放出来这一原理为依据,以样品在被覆盖前,它们的光释光信号都已经晒退回零为假设前提进行测年的。而风成沉积物是最符合这一假设的,所以光释光测年对于风成沉积物非常适合。本文对采自浑善达克沙地样品中的石英粗颗粒进行光释光测年,试图重建沙地的古环境演化过程。本文研究的样品分别采自浑善达克沙地的中部SG点(42°40'N,115°57'E)和东部YS点(43°14'N,116°49'E)。采样时,先挖大约30cm深,然后用锤子将金属小筒打入,拔出后,小筒用黑色塑料和胶带封死。到实验室后,小筒顶端大约1cm厚的样品用来测量 相似文献
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High-resolution loess deposits are widely distributed in Arid Central Asia (ACA) and provide important records associated with dust transportation, paleoenvironmental and paleoclimatic evolution. The chronology is the foundation of the research into loess deposits as an environmental archive. In recent decades, the gradually developed optical dating method has been increasingly matured and become an important approach to establishing the loess-paleosol sequences. Here, we summarized and discussed previous work on loess chronology mainly based on optical dating approach in ACA. The following understandings have been listed: ① In comparison with optical dating method, the suitable material for 14C dating is uncommon in ACA. However, the dating range of luminescence dating is more extensive, and the dating materials are accessible. Thus, the optical dating is widely applicable in the establishment of loess framework in this area. ② Until now, the quartz Single Aliquot Regeneration (SAR) method can be applied to the establishment of loess-paleosol sequence since last glacial period. But several issues remain unaddressed. For example, the Optically Stimulated Luminescence (OSL) signal sensitivity of quartz grains are low in some areas. Furthermore, the results of OSL dating of different grain sizes within a single sample are inconsistent in some areas. The solution of these problems still requires more methodological research. ③ The post-IR IRSL (pIRIR) and multiple elevated temperature stimulation (MET-pIRIR) protoCols of feldspar have basically overcome the anomalous fading issue in the traditional IRSL dating process. In ACA, the framework since MIS 7 can be established with K-feldspar luminescence dating method. Compared with quartz luminescence characteristics, the K-feldspar luminescence signals are more sensitive and exhibit a high saturation level. In specific applications, it is necessary to establish the age frame according to the luminescence sensitivity, the age of samples or other factors. 相似文献
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The application of both thermoluminescence and infrared stimulated luminescence dating to the extensively studied “classical” Hungarian loess/paleosol sequences from Basaharc, Mende, and Paks provides a reliable chronological framework and climatostratigraphic reconstruction for the last interglacial/glacial cycle. Based on this combined luminescence dating study a new chronology is proposed for the “Young Loess” in Hungary. Luminescence dating suggests that the loess below the MF2 horizon formed during the penultimate glaciation. The MF1 horizon probably formed during an interstade within oxygen isotope stage 3. For the youngest loess, overlying MF1, a very high accumulation rate was determined. Large time gaps occur above MF2 and MF1, indicating that most of the record of the last glaciation is missing in the standard sections at Basaharc, Mende, and Paks. Either large discontinuities or a very low accumulation rate occurred in all three type sections during the soil-forming periods. High-resolution studies of climatic proxies using this combined luminescence dating approach provide a reliable chronological framework for loess and loess derivatives of the last glacial cycle in Hungary, although a precise and complete chronostratigraphic reconstruction cannot be achieved from the incomplete records found at these sites. 相似文献
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释光测年是可对冰川地貌进行直接定年的一种测年技术,已被广泛应用于冰川沉积测年中,推动了第四纪冰川研究的深入发展。但冰川沉积释光测年还没有达到标准化的程度,实际应用中仍有不少问题需要探究,其中最受关注的是冰川沉积物释光信号晒退不完全的问题,即样品在埋藏前因曝光机会有限导致信号没有归零或仅部分归零。冰川沉积释光信号晒退程度与地貌部位和沉积环境密切相关。冰川沉积释光采样需注意几个方面：（1）详细的地貌学和沉积学调查及对采样点的选择;（2）较适合释光测年的冰水沉积和冰缘风成沉积采集及其与冰川作用期次的联系;（3）冰碛夹层中的冰水砂透镜体的选取;（4）冰碛垄采样时垂直与水平方向上的考量;（5）岩石释光测年的发展使砾石成为当前第四纪冰川释光测年采样的一种选择。室内进行释光等效剂量测试时,也有几个关键的选择：（1）粗颗粒石英光释光测年是末次冰期以来冰川作用的首选方法;（2）如果样品年代老于石英测年上限,或者石英不适合测试,则可考虑钾长石后红外高温释光测年方法;（3）单颗粒、小测片和岩石释光埋藏测年技术可以鉴别样品的晒退情况,是目前最适合冰川沉积释光测年的几种选择;（4）如有条件,尝试用不同矿物、不同粒径、不同方法进行测试对比和交叉检验。要获得第四纪冰川释光测年的最佳年代学结果,地貌学、沉积学和年代学的结合是非常必要的。 相似文献
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Continuing developmental work into optical dating has led to some clarification of the optical behaviour of quartz and feldspar sediment extracts. We have verified the key assumption intrinsic to the method — that the optical signal is zeroed completely upon exposure to daylight. We also show that the rate of zeroing in optical dating is much more rapid than it is in TL dating.Studies concerned with the extraction of the thermally stable signal from laboratory-irradiated samples showed that problems may arise from medium-to-high-temperature preheating of young samples. Optical alternatives to thermal stabilization were tested using dye and krypton lasers. Using a krypton laser we have succeeded in obtaining an equivalent dose of 0.0 ± 0.7 Gy for the quartz from a modern intertidal sand, and an average dose of 120 ± 22 Gy for the feldspar extract of a 70 ka sand unit. Both were obtained using six wavelengths, from the infrared to the violet, and no dependence on wavelength was found. We found that the photon energies of infrared and deep red light can stimulate luminescence in unirradiated quartz and feldspar extracts of sediments. This was not expected, and suggests that the process of trap emptying is more complex than we had envisioned, but implies a far greater than expected degree of technical flexibility for the optical dating method. 相似文献
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应用石英释光灵敏度进行物源研究是释光技术发展的新方向。回顾了石英释光灵敏度在测年研究中的发展现状,对其产生的机制、实验中的影响因素及其在测年中对灵敏度的监测、矫正等进行了介绍,详细介绍了空间尺度上不同沉积物(冰碛物、风成沉积物、水成沉积物)石英释光灵敏度的差异和时间序列上风成沉积物释光灵敏度的变化特征。据现有的研究成果分析,沉积历史和母岩来源对沉积物中石英的释光灵敏度的高低有重要的影响,因此可用它来追溯石英的物源。探讨该技术在物源研究领域存在的问题,对其发展前景进行了展望。 相似文献
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《Journal of Asian Earth Sciences》2010,39(6):274-282
In an active fold-and-thrust belt, sediment is commonly transported in the form of debris and colluviums, and the ages of such deposits can be important for seismic hazard assessment. These sediments are mainly transported by high concentration flows that travel very short distances before burial, and therefore have very few opportunities for daylight exposure and bleaching, which limits the application of luminescence dating in such environments. Luminescence studies on modern debris flow deposits and channel sediments in central Taiwan indicate a mixed population of bleached and unbleached grains. The well bleached grains constitute a small proportion of the sediments and could only be identified using the single grain dating technique; doing single aliquot analysis may result in overestimation of the age of such sediments by 3–25 ka. The data reveal that outwash sediments are better bleached than debris flow sediments. Our results show that quartz that has experienced partial resetting can be used for luminescence dating only through the use of the single grain technique. 相似文献
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This paper reports the application of optically stimulated luminescence (OSL) dating to relatively coarse grains (100–200 μm) of quartz extracted from loess. Two approaches were tested – a multiple aliquot technique and a new single aliquot approach, which is especially suited to the dating of small quantities of such grains found in some loess. The results are compared with infra‐red stimulated luminescence and thermoluminescence (TL) measurements on the finer‐grained (4–11 μm) polymineral fraction and TL measurements on the relatively coarse grains of quartz. The advantages of the new single aliquot (OSL) approach are described and the iterating, computer‐controlled measurement procedure is given. The automated iterative single aliquot regeneration (AISAR) method corrects for changes in luminescence sensitivity during the measurement sequence by monitoring the response to a test dose. Some initial measurements are presented for the loess section at Zemechy, Czech Republic, and these show that the AISAR method gives more precise results than those using a multiple aliquot method. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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A robust feldspar luminescence dating method for Middle and Late Pleistocene sediments 总被引：2，自引：0，他引：2
Jan‐Pieter Buylaert Mayank Jain Andrew S. Murray Kristina J. Thomsen Christine Thiel Reza Sohbati 《Boreas: An International Journal of Quaternary Research》2012,41(3):435-451
Luminescence dating is used extensively to provide absolute chronologies for Late Pleistocene sediments. Nowadays, most optical dates are based on quartz optically stimulated luminescence (OSL). However, the application of this signal is usually limited to the last ～100 ka because of saturation of the quartz luminescence signal with dose. In contrast, the feldspar infrared stimulated luminescence (IRSL) dose–response curve grows to much higher doses; this has the potential to extend the datable age range by a factor of 4–5 compared with quartz OSL. However, it has been known for several decades that this IRSL signal is unstable, and this instability often gives rise to significant age underestimation. Here we test against independent age control the recently developed feldspar post‐IR IRSL approach to the dating of sediments, which appears to avoid signal instability. A physical model explaining our observations is discussed, and the method is shown to be accurate back to 600 ka. The post‐IR IRSL signal is reduced by exposure to daylight more slowly than that from quartz and low‐temperature IRSL, preventing its general application to young (e.g. Holocene) sediments. Nevertheless, this new approach is widely applicable (feldspar of appropriate luminescence behaviour is even more ubiquitous than quartz). These characteristics make this a method of great importance for the dating of Middle and Late Pleistocene deposits. 相似文献