Preprints
https://doi.org/10.5194/egusphere-2023-1666
https://doi.org/10.5194/egusphere-2023-1666
16 Aug 2023
 | 16 Aug 2023

Regional variations in mineralogy of dust in ice cores obtained from northeastern and northwestern Greenland over the past 100 years

Naoko Nagatsuka, Kumiko Goto-Azuma, Koji Fujita, Yuki Komuro, Motohiro Hirabayashi, Jun Ogata, Kaori Fukuda, Yoshimi Ogawa-Tsukagawa, Kyotaro Kitamura, Ayaka Yonekura, Fumio Nakazawa, Yukihiko Onuma, Naoyuki Kurita, Sune Olander Rasmussen, Giulia Sinnl, Trevor James Popp, and Dorthe Dahl-Jensen

Abstract. To investigate regional and temporal variations in the sources and atmospheric transport processes for mineral dust deposited on the Greenland Ice Sheet, we analysed the morphology and mineral composition of dust in an ice core from northeastern Greenland (East Greenland Ice-Core Project, EGRIP), representing the period from 1910 to 2013, using scanning electron microscopy and energy-dispersive X-ray spectroscopy, and compared the results with those previously obtained for an ice core from northwestern Greenland (SIGMA-D). The composition of the SIGMA-D ice-core dust, comprising mostly silicate minerals, varied on a multi-decadal timescale due to an increased contribution of minerals originating from local ice-free areas during recent warming periods. In contrast, for the EGRIP ice-core dust, also consisting mostly of silicate minerals, there was relatively low compositional variation among the samples, suggesting that the mineral sources have not changed dramatically over the past 100 years. The subtle variation in the EGRIP ice-core mineral composition is likely due to a minor contribution of local dust. The type of silicate minerals differed significantly between the two ice cores; micas and chlorite, which form in cold dry regions, were abundant in the EGRIP ice core, whereas kaolinite, which forms in warm humid regions, was abundant in the SIGMA-D ice core. This indicates that the EGRIP ice-core dust likely originated from different geological sources than those for the SIGMA-D dust. A back-trajectory analysis indicated that the ice-core dust was transported from Northern Eurasia and North America to the EGRIP site, and that the contribution from each source was likely smaller and larger, respectively, than those for the SIGMA-D ice core. Furthermore, the higher illite content in the EGRIP ice core suggests dust transportation from Asian deserts. Although the back-trajectory analysis suggests that most of the air mass that arrived at the EGRIP site came from the Greenland coast, the mineral grain size and composition results showed that the local dust contribution was likely small.

Naoko Nagatsuka, Kumiko Goto-Azuma, Koji Fujita, Yuki Komuro, Motohiro Hirabayashi, Jun Ogata, Kaori Fukuda, Yoshimi Ogawa-Tsukagawa, Kyotaro Kitamura, Ayaka Yonekura, Fumio Nakazawa, Yukihiko Onuma, Naoyuki Kurita, Sune Olander Rasmussen, Giulia Sinnl, Trevor James Popp, and Dorthe Dahl-Jensen

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1666', Anonymous Referee #1, 14 Sep 2023
    • AC1: 'Reply on RC1', Naoko Nagatsuka, 23 Sep 2023
    • AC3: 'Reply on RC1', Naoko Nagatsuka, 19 Dec 2023
  • RC2: 'Comment on egusphere-2023-1666', Anonymous Referee #2, 18 Oct 2023
    • AC4: 'Reply on RC2', Naoko Nagatsuka, 19 Dec 2023
  • RC3: 'Comment on egusphere-2023-1666', Anonymous Referee #3, 20 Oct 2023
    • AC2: 'Reply on RC3', Naoko Nagatsuka, 19 Dec 2023
Naoko Nagatsuka, Kumiko Goto-Azuma, Koji Fujita, Yuki Komuro, Motohiro Hirabayashi, Jun Ogata, Kaori Fukuda, Yoshimi Ogawa-Tsukagawa, Kyotaro Kitamura, Ayaka Yonekura, Fumio Nakazawa, Yukihiko Onuma, Naoyuki Kurita, Sune Olander Rasmussen, Giulia Sinnl, Trevor James Popp, and Dorthe Dahl-Jensen
Naoko Nagatsuka, Kumiko Goto-Azuma, Koji Fujita, Yuki Komuro, Motohiro Hirabayashi, Jun Ogata, Kaori Fukuda, Yoshimi Ogawa-Tsukagawa, Kyotaro Kitamura, Ayaka Yonekura, Fumio Nakazawa, Yukihiko Onuma, Naoyuki Kurita, Sune Olander Rasmussen, Giulia Sinnl, Trevor James Popp, and Dorthe Dahl-Jensen

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Short summary
We present a new high-temporal-resolution record of mineral composition in a northeastern Greenland ice-core (EGRIP) over the past 100 years. The ice core dust composition and its variation differed significantly from a northwestern Greenland ice core, which is likely due to differences in the geological sources of the dust. Our results suggest that the EGRIP ice core dust was constantly supplied from Northern Eurasia, North America, and Asia with minor contribution from Greenland coast.