[A-CC33] Ice cores and paleoenvironmental modeling

[ACC33-02] Third Dome Fuji Ice Core Project - report on ice core processing during 2023-2025 -

*Ryo Inoue¹, Shuji Fujita^1,2, Motohiro Hirabayashi¹, Mai Matsumoto³, Hiroshi Ono⁴, Hayato Inoue⁵, Tomotaka Saruya¹, Ikumi Oyabu^1,2, Kyotaro Kitamura¹, Mai Suzuki², Fumio Nakazawa^1,2, Shun Tsutaki^1,2, Kenji Kawamura^1,2,6 (1.National Institute of Polar Research, Research Organization of Information and Systems, 2.The Graduate University for Advanced Studies, 3.Graduate School of Environmental Science, Hokkaido University, 4.Kitami Institute of Technology, 5.Graduate School of Science and Technology, Hirosaki University, 6.Japan Agency for Marine Science and Technology)

Keywords:Dome Fuji Deep Ice Coring Project 3, Japanese Antarctic Research Expedition, Ice core, Deep ice core

In the third Dome Fuji Ice Core Project, a pilot borehole was drilled to a depth of 126 m during the 2023-2024 season, followed by deep ice core drilling to a depth of 541 m in the 2024-2025 season. For the pilot core, various physical measurements (DEP: Dielectric Profiling, density, near-infrared reflectance, dielectric tensor, air permeability, and closed porosity) and gas analyses were initiated in Japan in 2024. Regarding the deep ice core, a core processing facility was established at Dome Fuji Observation Base II during the 2024-2025 season. To set up the core analysis facility, we installed the DEP measurement system, horizontal and vertical band saws, and a water isotope analyzer (Picarro) from December 3 to December 12. Core analysis began on December 16, starting with DEP measurements. The ice cores were then horizontally cut at a 6:4 weight ratio, further sectioned into 0.5 m segments, and packed into dedicated core cases. Additionally, water isotope analysis was conducted using saw dust produced during horizontal cutting. On-site core processing continued until January 5, completing core cutting and analysis down to a depth of 367 m. Beyond this depth, priority was given to specific depths designated for early analysis in Japan. Core cutting and analysis were conducted at approximately 10 m intervals down to 520 m, and a total of 35 m of ice core was transported to Japan.

We will report on the establishment of the core processing facility at Dome Fuji Observatin Base II during the 2024-2025 season and provide an overview of the progress in core analysis conducted both on-site and in Japan during the 2024-2025 period. Furthermore, we will discuss potential improvements for future on-site core analysis.