南極氷床とその生態系の過去のダイナミクスを理解する上で、このサンプルの重要性を説くスクリップス海洋学部の卒業生と同僚たち Scripps Oceanography alumnus and colleagues describe the sample’s importance in understanding past dynamics of the Antarctic ice sheet and its ecosystems
2023-03-09 カリフォルニア大学サンディエゴ校(UCSD)
Researchers captured the sediment sample in 2018 by cleanly boring a hole through over 3,500 feet of ice over Mercer Subglacial Lake. Here, a UV collar lights up the borehole. Photo: Kathy Kasic
国立科学財団が資金提供する「Subglacial Antarctic Lakes Scientific Access (SALSA)」プロジェクトの研究者チームは、現代の南極大陸の氷床下から最初の層状の堆積物を回収し、成功を収めました。
彼らが分析した堆積物サンプルからの研究成果は、南極氷床全体の大きなダイナミクスとその歴史、現在の氷床よりも小さかった時期を含む、重要な洞察を提供しました。彼らの研究成果は、南極の堆積物の記録に加え、南極が地球の海面変動にどのように貢献するかを理解する上でも意義があります。
＜関連情報＞
- https://today.ucsd.edu/story/researchers-extract-first-layered-lake-sediment-sample-from-subglacial-antarctica
- https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G50995.1/620903/The-life-and-death-of-a-subglacial-lake-in-West
西南極の氷河下湖の生と死 The life and death of a subglacial lake in West Antarctica
M.R. Siegfried;R.A. Venturelli;M.O. Patterson;W. Arnuk;T.D. Campbell;C.D. Gustafson;A.B. Michaud;B.K. Galton-Fenzi;M.B. Hausner;S.N. Holzschuh;B. Huber;K.D. Mankoff;D.M. Schroeder;P.T. Summers;S. Tyler;S.P. Carter;H.A. Fricker;D.M. Harwood;A. Leventer;B.E. Rosenheim;M.L. Skidmore;J.C. Priscu;the SALSA Science Team
Geology Published:09 Mar 2023
DOI:https://doi.org/10.1130/G50995.1
Over the past 50 years, the discovery and initial investigation of subglacial lakes in Antarctica have highlighted the paleoglaciological information that may be recorded in sediments at their beds. In December 2018, we accessed Mercer Subglacial Lake, West Antarctica, and recovered the first in situ subglacial lake-sediment record—120 mm of finely laminated mud. We combined geophysical observations, image analysis, and quantitative stratigraphy techniques to estimate long-term mean lake sedimentation rates (SRs) between 0.49 ± 0.12 mm a–1 and 2.3 ± 0.2 mm a–1, with a most likely SR of 0.68 ± 0.08 mm a–1. These estimates suggest that this lake formed between 53 and 260 a before core recovery (BCR), with a most likely age of 180 ± 20 a BCR—coincident with the stagnation of the nearby Kamb Ice Stream. Our work demonstrates that interconnected subglacial lake systems are fundamentally linked to larger-scale ice dynamics and highlights that subglacial sediment archives contain powerful, century-scale records of ice history and provide a modern processbased analogue for interpreting paleo–subglacial lake facies.
