近日，美国伍兹霍尔海洋研究所Jerey J. McGuire团队揭示了格陵兰冰盖下广泛沉积物的地震证据。2025年10月28日出版的《地质学》杂志发表了这项最新研究成果。

格陵兰冰盖的冰损失对全球海平面上升有重大贡献；然而，其幅度和对未来气候变化的敏感性仍然不确定，这在很大程度上是由于有关基础过程如何影响冰盖动力学的问题。具体而言，冰下沉积物在调节格陵兰冰盖动力学中的作用尚未得到很好的理解。融化和饱和的冰下沉积物加强了冰盖基底的滑动，因此有必要量化它们在格陵兰冰盖下的分布和性质。

研究组应用高频接收函数（RF）分析来研究近几十年来格陵兰冰盖上收集的冰下沉积物的地震数据。结果发现，观测到的RFs始终表现出相对于冰上的合成预测的到达时间延迟。硬床模型，表明在冰床界面广泛存在低速层。这种低速层可以用厚度达~200米的冰下沉积物来最好地解释。测绘结果表明，可变形沉积物比以前认识到的范围更广，但在空间上分布不均匀。沉积物厚度与模拟的基底热状态广泛相关，通常在解冻区域下方发现较厚和较弱的沉积物。这种沉积物的存在——甚至在目前没有基底融化的地区——可能是格陵兰冰盖部分地区未来动态变化的先决条件。该发现强调了将冰下沉积物特性纳入气候变暖下冰盖行为预测的重要性。

附：英文原文

Title: Seismic evidence of widespread sediments beneath the Greenland Ice Sheet

Author: Yan Yang, Wenyuan Fan, Mark D. Behn, Sarah B. Das, Jerey J. McGuire

Issue&Volume: 2025-10-28

Abstract: Ice loss from the Greenland Ice Sheet contributes significantly to global sea-level rise; however, its magnitude and sensitivity to future climate change remain uncertain in large part due to questions regarding how basal processes influence ice-sheet dynamics. Specifically, the role of subglacial sediments in regulating Greenland Ice Sheet dynamics is not well understood. Thawed and saturated subglacial sediments enhance ice-sheet basal sliding, making it essential to quantify their distribution and properties beneath the Greenland Ice Sheet. Here, we apply high-frequency receiver function (RF) analysis to investigate subglacial sediments using seismic data collected across the Greenland Ice Sheet over recent decades. We find that the observed RFs consistently exhibit arrival-time delays relative to synthetic predictions from iceoverhard bed models, indicating widespread low-velocity layers at the ice-bed interface. This low-velocity layer can be best explained by subglacial sediments with thicknesses up to ～200 m. The mapped results suggest that deformable sediments are more extensive than previously recognized but are distributed heterogeneously in space. Sediment thickness broadly correlates with modeled basal thermal state, with thicker and weaker sediments generally found beneath thawed regions. The presence of such sediments—even beneath regions not currently undergoing basal thaw—may precondition parts of the Greenland Ice Sheet for future dynamic change. Our findings highlight the importance of incorporating subglacial sediment properties into projections of ice-sheet behavior under a warming climate.

DOI: 10.1130/G53653.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G53653.1/662195/Seismic-evidence-of-widespread-sediments-beneathredirectedFrom=fulltext