A 100-Year record of mineralogical variations in Northeastern Greenland ice-core dust: Insights from individual particle analysis

Abstract. Understanding the spatial and temporal variations in mineral dust sources in Greenland ice cores during the Holocene is challenging due to low dust concentration. Here, we present the first continuous records of the size and composition, as well as the temporal variations in potential sources, of mineral dust preserved in a northeastern Greenland ice core (EGRIP) covering the period from 1910 to 2013. Using a multi-proxy provenance approach based on individual particle analysis, we reconstruct variations in ice-core dust sources. We apply a recently developed provenance tracing technique, namely scanning electron microscopy (SEM)-cathodoluminescence (CL) analysis of single quartz particles, and SEM energy-dispersive X-ray spectroscopy (EDS) analysis to the Greenland ice core. The SEM-CL/EDS results reveal that the primary dust sources in the EGRIP ice core are Asian (Gobi Desert) and African (Sahara Desert) deserts. Their relative contributions have shifted since the 1970s–1980s: the contribution from the Gobi Desert has decreased whereas that from the Sahara Desert has increased. Our findings demonstrate that SEM-CL analysis is a valuable tool for identifying ice-core dust sources and reconstructing their variations during periods of low dust concentration. Additionally, we compare the EGRIP ice-core dust records with those of a northwestern Greenland ice core (SIGMA-D) to determine spatial variations in potential dust sources within the Greenland Ice Sheet over the past 100 years. The results reveal that the variability and mineral composition of the EGRIP ice-core dust differs significantly from those of the SIGMA-D ice-core dust, indicating that the dust in these two ice cores was likely transported from different geological sources. The SIGMA-D ice-core dust exhibits multidecadal variations, reflecting increased dust from the Greenland coastal region during warmer periods. Conversely, the EGRIP ice-core dust shows low temporal variation, suggesting a smaller contribution from local sources.