To better understand the factors controlling the quartz luminescence sensitivity in loess deposits, samples from two loess sections in southern Tajikistan are investigated. Both pattern and amplitude in the variations of quartz luminescence sensitivity of these two sections are similar, showing higher values in pedocomplex units and lower values in the loess units. Similar trends of variation are found between the quartz luminescence sensitivity and climate proxies, including frequency-dependent magnetic susceptibility, median grain size and IRSL/[post-IR] OSL ratio. Laboratory experiments involving thermal activation and repeated bleaching/irradiation cycles reveal much larger sensitivity enhancement for samples with initial lower sensitivity from loess units than those from pedocomplex units with higher sensitivity. The observed systematic contrast in quartz luminescence sensitivity between the loess and pedocomplex units are interpreted as resulting from the differentiation of the weathering products from the source area and subsequent sensitization during the sedimentary transfer prior to deposition.

中文翻译：

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来自中亚塔吉克斯坦南部的黄土和pedocomplex样品的热和光学激发的发光灵敏度的变化

为了更好地了解控制黄土沉积物中石英发光敏感性的因素，对塔吉克斯坦南部两个黄土剖面的样品进行了调查。这两个部分的石英发光灵敏度的变化的模式和幅度都相似，显示出以pedocomplex单位较高的值和以黄土单位较低的值。在石英发光灵敏度和气候代理之间发现了类似的变化趋势，包括随频率变化的磁化率，中值晶粒尺寸和IRSL / [IR后] OSL比。涉及热活化和重复的漂白/辐照循环的实验室实验表明，与来自具有较高灵敏度的pedocomplex单元相比，最初来自黄土单元的灵敏度较低的样品的灵敏度增强要大得多。