We evaluate the paraglacial activity in Nexpayantla, a subtropical mountainous gorge in Popocatépetl volcano (Central Mexico), fully deglaciated in the 20th century. Glacial advances are evidenced by the presence of moraines. Fluvio‐glacial terraces and an alluvial megafan resulted from the gorge deglaciation. Current reworking of the glacigenic material is done by landslides and debris flows produced on the moraines and terraces. To study the different phases of mobilization of glacigenic sediment, we used an approach based on the study of the optically stimulated luminescence (OSL) signals obtained from a portable OSL (POSL) reader in samples extracted from both glacigenic and paraglacial deposits. The luminescence (POSL) results obtained at moraines increase as altitude decreases, which is expected for deglaciated valleys where the oldest moraines are located at lower elevations. We evaluate the grade of luminescence signal reset of the glacigenic sediments during the proglacial stage, and the subsequent deglaciation phases. Our results indicate that there is a marked transition between glacial and fluvially dominated processes at Nexpayantla Gorge. We find that the grade of luminescence signal resetting in the paraglacial deposits is a good indicator to trace paraglacial stages and the beginning of exhaustion of the paraglacial activity in mountain areas. OSL ages confirm that the oldest fluvio‐glacial terraces found at the middle sector of Nexpayantla Gorge are ~2 ka, which is also supported by an AMS ¹⁴C age. OSL dating was found challenging, since quartz grains have low sensitivity because of their volcanic origin; POSL signals, however, are in good agreement with the location and distribution of geomorphic markers. We propose that luminescence data obtained from the POSL unit can be useful to provide information about sediment mobilization in paraglacial environments during different climatic pulses – even for the case where mineral grains have low sensitivity, such as in volcanic sediments. © 2020 John Wiley & Sons, Ltd.

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使用OSL和14C评估Nexpayantla Gorge（中部墨西哥Popocatépetl火山）的滑冰过程

我们评估了Nexpayantla的滑冰活动，Nexpayantla是Popocatépetl火山（中部墨西哥）的亚热带山区峡谷，在20世纪完全冰川消融。冰rain的存在证明了冰川的发展。峡谷冰消造成了河流冰川阶地和冲积巨扇。当前对冰川成因物质的改造是通过滑坡和在沟壑和阶地上产生的泥石流来完成的。为了研究动员成冰沉积物的不同阶段，我们使用了一种方法，该方法基于对从成冰和冰河沉积物中提取的样品中的便携式OSL（POSL）阅读器获得的光激发发光（OSL）信号的研究。随着高度的降低，在冰rain上获得的发光（POSL）结果增加，对于最古老的冰rain位于较低海拔的冰河谷，这是可以预期的。我们评估了冰川期沉积过程以及随后的冰消阶段的发光信号重置的等级。我们的结果表明，在Nexpayantla Gorge，冰川和河流主导的过程之间存在明显的过渡。我们发现，冰川期沉积物中的发光信号重置等级是追踪冰川期和山区冰川活动耗尽的良好指示器。OSL年龄证实，在Nexpayantla峡谷中段发现的最古老的河冰阶地约为2 ka，这也得到了AMS的支持 我们评估了冰川期沉积过程以及随后的冰消阶段的发光信号重置的等级。我们的结果表明，在Nexpayantla Gorge，冰川和河流主导的过程之间存在明显的过渡。我们发现，冰川期沉积物中的发光信号重置等级是追踪冰川期和山区冰川活动耗尽的良好指示器。OSL年龄证实，在Nexpayantla峡谷中段发现的最古老的河冰阶地约为2 ka，这也得到了AMS的支持 我们评估了冰川期沉积过程以及随后的冰消阶段的发光信号重置的等级。我们的结果表明，在Nexpayantla Gorge，冰川和河流主导的过程之间存在明显的过渡。我们发现，冰川期沉积物中的发光信号重置等级是追踪冰川期和山区冰川活动耗尽的良好指示器。OSL年龄证实，在Nexpayantla峡谷中段发现的最古老的河冰阶地约为2 ka，这也得到了AMS的支持 我们发现，冰川期沉积物中的发光信号重置等级是追踪冰川期和山区冰川活动耗尽的良好指示器。OSL年龄证实，在Nexpayantla峡谷中段发现的最古老的河冰阶地约为2 ka，这也得到了AMS的支持 我们发现，冰川期沉积物中的发光信号重置等级是追踪冰川期和山区冰川活动耗尽的良好指示器。OSL年龄证实，在Nexpayantla峡谷中段发现的最古老的河冰阶地约为2 ka，这也得到了AMS的支持¹⁴ C年龄。发现OSL测年具有挑战性，因为石英粒由于其火山成因而敏感性较低。但是，POSL信号与地标标记的位置和分布非常吻合。我们认为，从POSL装置获得的发光数据可用于提供有关在不同气候脉冲下冰川环境中泥沙动员的信息，即使对于矿物颗粒敏感性较低的情况（例如在火山沉积物中）也是如此。分级为4 +©2020 John Wiley＆Sons，Ltd.