当前位置: X-MOL 学术Earth Planet. Sci. Lett. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Northwest Pacific ice-rafted debris at 38°N reveals episodic ice-sheet change in late Quaternary Northeast Siberia
Earth and Planetary Science Letters ( IF 5.3 ) Pub Date : 2021-01-01 , DOI: 10.1016/j.epsl.2020.116650
A.P. McCarron , G.R. Bigg , H. Brooks , M.J. Leng , J.D. Marshall , V. Ponomareva , M. Portnyagin , P.J. Reimer , M. Rogerson

Abstract The ice-rafted-debris (IRD) record of the open Northwest Pacific points towards the existence of substantial glacial ice on the Northeast Siberian coast during the late Quaternary. However, the scale and timing of glaciation and de-glaciation remains controversial due to the dearth of both onshore and offshore records. Existing IRD data suggests at least one event of dynamic and abrupt change during mid-late Marine Isotope Stage (MIS 3) which mimics the massive collapse of the Laurentide ice sheet during Heinrich Events. It is uncertain whether other events of this magnitude occurred during the late Quaternary. Here we present a ∼160,000 yr IRD series, planktic foraminiferal counts and an age model, derived from a benthic δ 18 O curve, radiocarbon dates and tephrochronology, from core ODP 1207A (37.79°N, 162.75°E), revealing the presence of low but episodic flux of IRD. We conclude that glacial Northwest Pacific icebergs spread further south than previously thought, with icebergs emanating from Northeast Siberia being transported to the transition region between the subpolar and subtropical waters, south of the subarctic front during at least the Quaternary's last two glacial periods. The episodic nature of the 1207A IRD record during the last glacial, combined with coupled climate-iceberg modelling, suggests occasional times of much enhanced ice flux from the Kamchatka-Koryak coast, with other potential sources on the Sea of Okhotsk coast. These findings support the hypothesis of a variable but extensive ice mass during the last glacial over Northeast Siberia, particularly early in the last glacial period, behaving independently of North American and Eurasian ice masses. In strong contrast, IRD was absent during much of the penultimate glacial Marine Isotope Stage (MIS) 6 suggesting the possibility of very different Northeast Siberian ice coverage between the last two glacial periods.

中文翻译:

西北太平洋 38°N 的冰筏碎片揭示了晚第四纪东北西伯利亚的偶发冰盖变化

摘要 开放的西北太平洋的冰筏碎片 (IRD) 记录表明晚第四纪东北西伯利亚海岸存在大量冰川冰。然而,由于陆上和海上记录的缺乏,冰川作用和去冰川作用的规模和时间仍然存在争议。现有的 IRD 数据表明,在中晚期海洋同位素阶段 (MIS 3) 中至少发生了一个动态和突然变化的事件,它模仿了海因里希事件期间劳伦泰德冰盖的大规模崩塌。尚不确定在第四纪晚期是否发生过这种规模的其他事件。在这里,我们展示了 160,000 年的 IRD 系列、浮游有孔虫计数和年龄模型,这些模型来自底栖 δ 18 O 曲线、放射性碳日期和年代学,来自核心 ODP 1207A(37.79°N,162.75°E),揭示了 IRD 的低但偶发性通量的存在。我们得出结论,西北太平洋冰川冰山比以前认为的更向南扩散,至少在第四纪的最后两个冰期期间,来自西伯利亚东北部的冰山被运送到亚北极锋以南的副极地和亚热带水域之间的过渡区。上次冰川期间 1207A IRD 记录的情节性质,结合气候-冰山耦合模型,表明来自堪察加-科里亚克海岸的冰通量偶尔会大幅增加,而鄂霍次克海沿岸的其他潜在来源。这些发现支持了在西伯利亚东北部最后一次冰川期间存在可变但广泛的冰块的假设,特别是在最后一次冰川期早期,行为独立于北美和欧亚冰块。与此形成鲜明对比的是,在倒数第二个冰期海洋同位素阶段 (MIS) 6 的大部分时间里,IRD 都不存在,这表明最后两个冰期之间东北西伯利亚冰覆盖率可能非常不同。
更新日期:2021-01-01
down
wechat
bug