近日，美国波士顿学院Danielle E. LeBlanc及其团队在研究更新世间冰期劳伦泰德冰盖的持续存在方面取得新进展。2023年3月22日出版的《地质学》发表了这项成果。

该团队表明，在冰筏碎片中的原位宇宙成因核素，劳伦泰德冰盖在第四纪的间冰期可能比通常认为的更持久。海洋岩芯沉积物中²⁶Al/¹⁰Be比值(表明源区被埋藏)较低，表明沉积物源区在过去100万年中只经历了短暂的(大约几千年的时间)和/或不频繁的无冰间冰期。

研究结果表明，只有当气候作用力达到与全新世早期相当的水平时，劳伦泰德冰盖的完全消冰才可能发生，使得目前的间冰期与更新世中期至晚期的间冰期不一致。

据介绍，虽然今天在格陵兰岛以外的北半球没有冰盖，但不确定在大多数其他第四纪间冰期是否也是如此。

附：英文原文

Title: Laurentide Ice Sheet persistence during Pleistocene interglacials

Author: Danielle E. LeBlanc, Jeremy D. Shakun, Lee B. Corbett, Paul R. Bierman, Marc W. Caffee, Alan J. Hidy

Issue&Volume: 2023-03-22

Abstract: While there are no ice sheets in the Northern Hemisphere outside of Greenland today, it is uncertain whether this was also the case during most other Quaternary interglacials. We show, using in situ cosmogenic nuclides in ice-rafted debris, that the Laurentide Ice Sheet was likely more persistent during Quaternary interglacials than often thought. Low ²⁶Al/¹⁰Be ratios (indicative of burial of the source area) in marine core sediment suggest sediment source areas experienced only brief (on the order of thousands of years) and/or infrequent ice-free interglacials over the past million years. These results imply that complete Laurentide deglaciation may have only occurred when climate forcings reached levels comparable to those of the early Holocene, making our current interglacial unusual relative to others of the mid-to-late Pleistocene.

DOI: 10.1130/G50820.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G50820.1/621217/Laurentide-Ice-Sheet-persistence-duringredirectedFrom=fulltext