中国北方沙漠—黄土系统的选频释光特性研究

【作者】 刘超；

【导师】 魏明建； 李虎侯；

【作者基本信息】 首都师范大学 ， 自然地理学， 2011， 博士

【摘要】 选频释光是一种对于释光现象精细化研究的新技术。地质样品释光特性是其成分的晶格结构决定的,与其所处的地理环境相关。应用选频释光技术研究地质样品所承载的地理环境信息,需要确定测定样品的仪器条件与技术流程。将样品的选频释光特性具体化为分频接收光谱、发光波长统计、光子计数最大值所在波长、特征波长以及特殊波长等指标。这些指标的组合具有空间——时间差异,代表着不同地理事物的地学属性。通过对中国北方科尔沁、浑善达克、巴丹吉林、毛乌素、腾格里以及库布齐沙漠表层砂的测定,获取了各沙漠表层砂的选频释光特性指标组合。其结果表明各沙漠表层砂的选频释光特性指标组合存在差异,可以表征各沙漠物质的矿物成分差别,从而达到区分各沙漠表层砂的目的。黄土与沙漠具有物质上的联系,构成了环境耦合体系。北京西山地区的晚更新世黄土地层及全新世地层记录了其形成时期的降尘信息。应用选频释光技术提取其中关于粉尘物质来源信息的测定结果表明,不同地层单元的样品,其选频释光特性指标存在差异。一些波长的释光光子可以作为区分样品所属地层的依据。对比沙漠物质选频释光特性,发现末次冰期时期形成的马兰黄土地层其物质选频释光特性与库布齐沙漠物质选频释光特征相似。本研究的主要创新点为：第一,将选频释光技术应用于地学研究,为地质样品建立了一个新的指标类型,并形成了一组指标体系；第二,通过对沙漠表层砂样品的选频释光测定,逐步建立起一套选频释光测定方法；第三,通过分析比较沙漠表层砂与北京西山黄土地层样品的选频释光特性,确定库布齐沙漠为末次冰期北京地区粉尘沉积物的物源。选频释光技术可以区分不同空间位置和经历不同时间——空间变化的地质样品,为地学研究提供一种新类型的指标。作为一种具有地学应用潜力新技术,选频释光仍需在广度和深度两个方面开展进一步的研究。更多还原

【Abstract】 The selected frequency luminescence is a new technology for meticulous study on the phenomenon of luminescence. The character of geological samples is determined by its composition crystal lattice structure. It is influenced by the geographical environment where the samples present. The instrument conditions and technical process of measurement should be defined before detecting the geographical environment information carried by geological samples. The characters include the dividing frequency receiving spectra, light wavelength statistic, wavelength of maximum photon counting, characteristic wavelength and extraordinary wavelength. The time-spatial difference is exhibited by the characters which represent the geographic properties of geographical object.Frequency luminescence characters index of surface on the deserts were got by measuring the samples from Horqin, Hushandake, Badain Jaran, Mu Us, Tengger and Hobq desert. The results showed that the frequency luminescence characters index of these deserts are different. And these characters can be used to represent the geographical properties.An environmental coupling system is composed by Loess and the deserts through the material relation. Information of falling dust in the period of late Pleistocene and Holocene is recorded by loess strata in the area of Xishan, Beijing. The result of measurement shows, there are some difference in the frequency luminescence characters index of different deserts, through the frequency luminescence test. Some luminescence photon with the special wavelength can be used to distinguish strata. Contrasted by the luminescence characters index of surface on the deserts, the samples of Malan Loess in Xishan area and the samples from Hobq are similar on the frequency luminescence characters index.The innovation of this study include:1. Applying the technique of selected luminescence for studying geography, and a new type of index system is established. 2. A set of measuring method is established through measuring the sample from the surface of deserts.3. Hobq desert is determined as the source of the material of dsut in Beijing area on the last glaciations period, through contrasting the selected frequency luminescence character from the sample of deserts and the strata in Xishan, Beijing.The result shows selected frequency luminescence technology can be used to distinguish geological samples which present different location or undergo time-spatial process. A new type of index is provided for geographical study. But as a new technology with potential of geosciences application, more study should be developed both in depth and width in the area of selected frequency luminescence.更多还原