[A-CC27] Ice cores and paleoenvironmental modeling

[ACC27-08] Regional variations in mineralogy of dust in ice cores obtained from northeastern and northwestern Greenland over the past 100 years

*Naoko Nagatsuka¹, Kumiko Goto-Azuma^1,2, Koji Fujita³, Yuki Komuro⁴, Motohiro Hirabayashi¹, Jun Ogata¹, Kaori Fukuda¹, Yoshimi Ogawa-Tsukagawa¹, Kyotaro Kitamura¹, Ayaka Yonekura⁶, Fumio Nakazawa¹, Yukihiko Onuma⁵, Naoyuki Kurita³, Sune Olander Rasmussen⁷, Giulia Sinnl⁷, Trevor James Popp⁷, Dorthe Dahl-Jensen⁷ (1.National Institute of Polar Research, 2.SOKENDAI, 3.Nagoya University, 4.Laboratory for Environmental Research at Mount Fuji, 5.JAXA, 6.Marine Works Japan Ltd, 7.University of Copenhagen)

Keywords:Ice core dust sources, Greenland, SEM-EDS analysis

Mineral dust preserved in Greenland ice cores provide valuable insights into past climate and environmental changes. However, spatial and temporal variations in the Greenland ice-core dust sources during interglacial periods remain unclear because of low dust concentration. Here, we present the first continuous records of size, composition, and potential sources of silicate mineral dust from a northeastern Greenland ice core (EGRIP) over the last 100 years, using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). We highlight significant distinctions from a northwestern Greenland ice core (SIGMA-D). The EGRIP ice core dust displays low temporal variation, suggesting that the sources did not change dramatically during this period. Low compositional variability is distinct from the dust observed in the SIGMA-D ice-core, which shows multi-decadal variations due to increased contribution from the Greenland coastal region during warm periods. The subtle compositional variation in the EGRIP ice core dust likely reflects a significantly smaller contribution of local dust. Furthermore, significant differences in silicate mineral composition between the two ice cores imply transport from distinct geological origins. Analysis of mineralogy and trajectory data indicate potential dust sources, including Asian deserts, Northern Eurasia, and North America. The EGRIP ice core shows higher contributions from Asian deserts and Northern Eurasia, but lower from North America compared to the SIGMA-D ice core. Although subtle variations in dust compositions sugest no significant changes in the EGRIP ice-core dust sources, there may have been slight shifts during specific periods. A ternary clay mineralogy diagram and the elemental concentration ratios of the ice-core dust indicate a change in primary dust source contribution after 1970-1980. This change could be influenced by variations in atmospheric oscillations (such as the North Atlantic Oscillation and Atlantic Multidecadal Oscillation) and the input of Asian dust.