Our study is the first to demonstrate a high-temporal-resolution record of mineral composition in a Greenland ice core over the past 100 years. To reconstruct past variations in the sources and transportation processes of mineral dust in northwestern Greenland, we analysed the morphology and mineralogical composition of dust in the SIGMA-D ice core from 1915 to 2013 using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results revealed that the ice core dust consisted mainly of silicate minerals and that the composition varied substantially on multi-decadal and inter-decadal scales, suggesting that the ice core minerals originated from different geological sources in different periods during the past 100 years. The multi-decadal variation trend differed among mineral types. Kaolinite, which generally formed in warm and humid climatic zones, was abundant in colder periods (1950–2004), whereas mica, chlorite, feldspars, mafic minerals, and quartz, which formed in arid, high-latitude, and local areas, were abundant in warmer periods (1915–1949 and 2005–2013). Comparison to Greenland surface temperature records indicates that multi-decadal variation in the relative abundance of these minerals was likely affected by local temperature changes in Greenland. Trajectory analysis shows that the minerals were transported mainly from the western coast of Greenland in the two warming periods, which was likely due to an increase in dust sourced from local ice-free areas as a result of shorter snow/ice cover duration in the Greenland coastal region during the melt season caused by recent warming. Meanwhile, ancient deposits in northern Canada, which were formed in past warmer climates, seem to be the best candidate during the colder period (1950–2004). Our results suggest that SEM–EDS analysis can detect variations in ice core dust sources during recent periods of low dust concentration.

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过去 100 年来从格陵兰岛西北部获得的冰芯中尘埃矿物学的变化

我们的研究首次展示了过去 100 年来格陵兰冰芯中矿物成分的高时间分辨率记录。为了重建格陵兰西北部矿物粉尘来源和运输过程的过去变化，我们使用扫描电子显微镜 (SEM) 和能量色散 X- 分析了 1915 年至 2013 年 SIGMA-D 冰芯中粉尘的形态和矿物组成。射线光谱（EDS）。结果表明，冰芯尘埃主要由硅酸盐矿物组成，其成分在多年代际和年代际尺度上变化很大，表明冰芯矿物在过去100年的不同时期来自不同的地质来源。不同矿物类型的年代际变化趋势不同。高岭石，一般形成于温暖潮湿的气候带，在寒冷时期（1950-2004）丰富，而在干旱、高纬度和局部地区形成的云母、绿泥石、长石、镁铁质矿物和石英则丰富。暖期（1915-1949 和 2005-2013）。与格陵兰地表温度记录的比较表明，这些矿物相对丰度的数十年变化可能受到格陵兰当地温度变化的影响。轨迹分析表明，在两个变暖期，矿物质主要来自格陵兰岛西海岸，这可能是由于格陵兰岛冰雪覆盖持续时间较短，导致当地无冰区的灰尘增加所致近来变暖导致的融化季节的沿海地区。同时，加拿大北部的古老矿床形成于过去较温暖的气候中，似乎是较冷时期（1950-2004 年）的最佳候选者。我们的结果表明，SEM-EDS 分析可以检测到近期低粉尘浓度期间冰芯粉尘源的变化。