2025-12-11 インペリアル・カレッジ・ロンドン（ICL）
＜関連情報＞
- https://www.imperial.ac.uk/news/articles/engineering/earth-science/2025/ancientantarcticrivers-challengetheory-of-aflatlandscape-as-mission-for-climatecluesbeneath-antarctic-icegets-underway-/
- https://www.science.org/doi/10.1126/sciadv.aea2373
アムンゼン海湾堆積物の起源分析による始新世南極河川流域の復元 Reconstructing Eocene Antarctic river drainage from provenance analysis of Amundsen Sea embayment sediments
James W. Marschalek, Tina van de Flierdt, Christine S. Siddoway, Stuart N. Thomson, […] , and Pieter Vermeesch
Nature Advances Published:10 Dec 2025
DOI:https://doi.org/10.1126/sciadv.aea2373
Abstract
Sedimentary records can illuminate relationships between the climate, topography, and glaciation of West Antarctica by revealing its Cenozoic topographic and paleoenvironmental history. Eocene fluvial drainage patterns have previously been inferred using geochemical provenance data from an ~44– to 34–million year deltaic sandstone recovered from the Amundsen Sea Embayment. One interpretation holds that a low-relief, low-lying West Antarctic landscape supported a >1500-kilometer transcontinental river system. Alternatively, higher-relief topography in central West Antarctica formed a drainage divide between the Ross and Amundsen seas. Here, zircon U-Pb data from Amundsen Sea Embayment sediments are examined alongside known regional bedrock provenance signatures. These analyses suggest that all observed provenance indicators in the Eocene sandstone derive from West Antarctic rocks. This implies that a local river system flowed off a West Antarctic drainage divide, helping constrain the mid-Late Eocene evolution of West Antarctic topography with implications for the history of rifting and the characteristics of sediments infilling interior basins.
