Sedimentary record from the Canada Basin, Arctic Ocean: implications for late to middle Pleistocene glacial history
Sedimentary record from the Canada Basin, Arctic Ocean: implications for late to middle Pleistocene glacial history
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北冰洋加拿大盆地的沉积记录：对晚中更新世冰川历史的影响
DOI：
10.5194/cp-13-511-2017
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发表时间：
2017-05-23
影响因子：
4.3
通讯作者：
Wang, Xuchen
中科院分区：
文献类型：
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作者：
Dong, Linsen;Liu, Yanguang;Wang, Xuchen
从北冰洋加拿大盆地收集的沉积物核心 ARC4-BN05 覆盖了第四纪晚期到中期（海洋同位素阶段 - MIS - 1-15，约 0.5-0.6 Ma），根据与早期提出的北冰洋地层和最年轻沉积物的 AMS(14)C 测年的相关性估计。对 ARC4-BN05 岩心中粘土和散装矿物学以及颗粒尺寸、Ca 和 Mn 含量以及浮游有孔虫数量的详细检查提供了有关沉积环境和来源的重要新信息。我们使用粗碎片含量的增加作为北冰洋西部边缘冰川崩塌事件的指标，并从矿物学成分中确定这些事件的来源。值得注意的是，白云石碎片的峰值，包括大型落石，追踪劳伦泰德冰盖（LIS）向北冰洋的排放事件。主要的 LIS 输入发生在估计为 MIS 3、MIS 5 和 7 内事件、MIS 8 和 MIS 10 的地层区间内。东西伯利亚冰盖 (ESIS) 的输入是根据与粗沉积物相关的蒙皂石、高岭石和绿泥石的峰值推断的。主要的 ESIS 沉积事件发生在估计为 MIS 4、MIS 6 和 MIS 12 的区间内。LIS 与 ESIS 输入的差异可以通过不同海平面的冰盖构造、沉积物输送机制（冰山漂流、悬浮羽流和泥石流）和地表环流来解释。沉积物输入模式的长期变化，在估计的 MIS 7-8 边界（约 0.25 Ma）附近出现明显的阶跃变化，可能表明北极西部边缘的整体冰川扩张，特别是在北美。
Sediment core ARC4-BN05 collected from the Canada Basin, Arctic Ocean, covers the late to middle Quaternary (Marine Isotope Stage - MIS - 1-15, ca. 0.5-0.6 Ma) as estimated by correlation to earlier proposed Arctic Ocean stratigraphies and AMS(14)C dating of the youngest sediments. Detailed examination of clay and bulk mineralogy along with grain size, content of Ca and Mn, and planktic foraminiferal numbers in core ARC4-BN05 provides important new information about sedimentary environments and provenance. We use increased contents of coarse debris as an indicator of glacier collapse events at the margins of the western Arctic Ocean, and identify the provenance of these events from mineralogical composition. Notably, peaks of dolomite debris, including large dropstones, track the Laurentide Ice Sheet (LIS) discharge events to the Arctic Ocean. Major LIS inputs occurred during the stratigraphic intervals estimated as MIS 3, intra-MIS 5 and 7 events, MIS 8, and MIS 10. Inputs from the East Siberian Ice Sheet (ESIS) are inferred from peaks of smectite, kaolinite, and chlorite associated with coarse sediment. Major ESIS sedimentary events occurred in the intervals estimated as MIS 4, MIS 6 and MIS 12. Differences in LIS vs. ESIS inputs can be explained by ice-sheet configurations at different sea levels, sediment delivery mechanisms (iceberg rafting, suspension plumes, and debris flows), and surface circulation. A long-term change in the pattern of sediment inputs, with an apparent step change near the estimated MIS 7-8 boundary (ca. 0.25 Ma), presumably indicates an overall glacial expansion at the western Arctic margins, especially in North America.