Microparticles in a deep ice core drilled at NEEM, Greenland: cryogenic scanning electron microscopic observations of location, size, shape, and constituent elements

• Format: Article in Journal/Newspaper
• Language: English
• Published: National Institute of Polar Research 2021
• Subjects: microparticle; microscope image; X-ray spectrum(-ra); chemical component; North Greenland Eemian Ice Drilling (NEEM) ice core; cryogenic scanning electron microscopy (cryo-SEM); energy dispersive X-ray spectroscopy (EDS); in-situ analysis; Greenland; ice core; North Greenland
• Online Access: http://id.nii.ac.jp/1434/00000031/; https://pdr.repo.nii.ac.jp/?action=repository_uri&item_id=45; https://pdr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=45&item_no=1&attribute_id=22&file_no=1; https://pdr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=45&item_no=1&attribute_id=22&file_no=2; https://pdr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=45&item_no=1&attribute_id=22&file_no=3

This report presents the analysis of microparticles contained in the deep ice core drilled at the North Greenland Eemian Ice Drilling (NEEM) site, using a cryogenic scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDS). By implementing additional optical microscopic analysis prior to cryogenic SEM/EDS analysis, it was possible to exclude artifacts formed during the cryogenic SEM/EDS experiments. The examined ice core samples were cut from depths corresponding to five different climate stages, from the Holocene period through the last interglacial epoch. Overall, 514 microparticles were observed via SEM, and 151 of those were also analyzed based on their EDS spectra to determine their chemical compositions. A catalog containing the details of all the observed microparticles was then constructed. The catalog presents optical and secondary electron images of microparticles, an area-equivalent diameter and aspect ratio of each microparticle, and its distance from the nearest grain boundary and air-inclusion (i.e., air bubble, hydrate) or plate-like inclusion. For microparticles analyzed with EDS, numerical data regarding the X-ray count, weight ratio, and atomic ratio are also included, and the atomic ratio is shown as a pie chart. In this report, we describe how the observations and analyses were carried out and how the catalog data were organized. The catalog is valuable for studies regarding the general paleoenvironment and the relationship between microparticles and the physical properties of ice in polar ice sheets.