近日，英国伦敦帝国理工学院James W. Marschalek团队报道了从阿蒙森海河口沉积物物源分析重建始新世南极河流流域。2025年12月12日出版的《科学进展》杂志发表了这项成果。
沉积记录能揭示西南极洲新生代地形与古环境历史，从而阐明该地区气候、地形与冰川作用之间的关联。先前研究曾通过分析阿蒙森海海槽获取的约4400万年至3400万年三角洲砂岩的地球化学物源数据，推断始新世河流水系模式。一种观点认为，当时平坦低洼的西南极洲地形曾发育长达1500公里以上的跨大陆河流系统；另一种观点则主张，西南极洲中部的高起伏地形形成了罗斯海与阿蒙森海之间的分水岭。
研究组结合锆石U-Pb测年数据与已知区域基岩物源特征，对阿蒙森海海槽沉积物进行分析。结果表明，始新世砂岩中所有观测到的物源指标均来自西南极洲岩体，这暗示当时存在发源于西南极洲分水岭的局部河流系统。该发现为限定西南极洲始新世中晚期的地形演化提供了关键依据，同时为了解裂谷作用历史及内陆盆地沉积物充填特征提供了新视角。
附：英文原文
Title: Reconstructing Eocene Antarctic river drainage from provenance analysis of Amundsen Sea embayment sediments
Author: James W. Marschalek, Tina van de Flierdt, Christine S. Siddoway, Stuart N. Thomson, Guy J. G. Paxman, Stewart S. R. Jamieson, Ethan Conrad, Kathy J. Licht, Sidney R. Hemming, Michael J. Bentley, Claus-Dieter Hillenbrand, James A. Smith, Johann P. Klages, Matthew Fox, Guido Pastore, Pieter Vermeesch
Issue&Volume: 2025-12-12
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.
DOI: aea2373
Source: https://www.science.org/doi/10.1126/sciadv.aea2373