美国伍兹霍尔海洋研究Roger C. Creel团队报道，末次间冰期不对称冰盖融化驱动的冰川均衡调整导致多个局部海平面峰值。该研究于2024年12月17日发表于国际一流学术期刊《地质学》杂志上。

全球平均海平面（GMSL）在末次间冰期 (LIG, 129-116ka)的变化，为理解冰盖如何响应变暖提供了视角。已有研究对LIG相对海平面（RSL）记录的多个峰值进行观测，结合劳伦冰盖（LIS）在LIG之前崩塌的假设，以推断格陵兰岛和南极冰盖的融化历史以及LIG全球平均海平面的振荡。

然而，劳伦冰盖在ca.125ka时的爆发洪水和广泛的LIG早期南极融化表明，即使在南极融化加速的情况下，劳伦冰盖残余物在LIG中存在的时间可能也比通常认为的更长。

研究人员探讨了全新世早期劳伦持续和南极崩塌的同时发生，对冰川均衡调整和海平面的影响。在实验模型中，研究人员通过平衡过量的劳伦冰和LIG早期的南极冰川融化，将GMSL保持在128ka至117ka的当前水平（即GMSL=0）。结果发现，由于冰川均衡调整，这种同步但不对称的冰川变化形成了多个RSL峰，其中北美附近的RSL峰间隔约为4.2±2.5m，印度洋周围的RSL峰间隔约为1.3±0.7m。这种空间模式与观测相似。

这些结果表明，LIG RSL的多个峰值可能发生在北半球和南半球之间的不对称冰变化的情况下，这些变化加起来很小，如果有的话。这项工作强调了LIG建模研究的必要性，以考虑即使在接近恒定的GMSL下也可能发生动态冰冻圈变化。

附：英文原文

Title: Glacial isostatic adjustment driven by asymmetric ice sheet melt during the Last Interglacial causes multiple local sea-level peaks

Author: Roger C. Creel, Jacqueline Austermann

Issue&Volume: 2024-12-17

Abstract: Global mean sea-level (GMSL) change during the Last Interglacial (LIG, 129116 ka) gives perspective on how ice sheets respond to warming. Observations of multiple peaks in LIG relative sea level (RSL) records, combined with an assumption that the Laurentide Ice Sheet (LIS) collapsed prior to the LIG, have been used to infer Greenland and Antarctic ice sheet melt histories as well as oscillations in LIG GMSL. However, evidence for an LIS outburst flood at ca. 125 ka and extensive early-LIG Antarctic melt suggests that Laurentide remnants may have persisted longer into the LIG than typically thought even as Antarctic melt accelerated. Here, we explore the effect of concurrent early-Holocene Laurentide persistence and Antarctic collapse on glacial isostatic adjustment and sea level. In our models, we hold GMSL constant at present levels (i.e., GMSL = 0) from 128 ka to 117 ka by balancing excess Laurentide ice with early-LIG Antarctic melt. We find that due to glacial isostatic adjustment, this synchronous but asymmetric ice change causes multiple RSL peaks, separated by ～4.2 ± 2.5 m of RSL fall near North America and ～1.3 ± 0.7 m around the Indian Ocean. This spatial pattern resembles observations. These results show that multiple peaks in LIG RSL could have occurred with asymmetric ice changes between the Northern and Southern Hemisphere that sum to little, if any, change in GMSL. Our work highlights the need for LIG modeling studies to consider that dynamic cryospheric changes can occur even with near-constant GMSL.

DOI: 10.1130/G52483.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52483.1/650795/Glacial-isostatic-adjustment-driven-by-asymmetricredirectedFrom=fulltext