Holocene Interactions Between Glacier Retreat, Sea Ice Formation, and Atlantic Water Advection at the Inner Northeast Greenland Continental Shelf
Holocene Interactions Between Glacier Retreat, Sea Ice Formation, and Atlantic Water Advection at the Inner Northeast Greenland Continental Shelf
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DOI：
10.1029/2020pa004019
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发表时间：
2020-11
影响因子：
3.5
通讯作者：
Nicole Syring;J. Lloyd;R. Stein;K. Fahl;D. Roberts;L. Callard;C. O'cofaigh
中科院分区：
文献类型：
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作者：
Nicole Syring;J. Lloyd;R. Stein;K. Fahl;D. Roberts;L. Callard;C. O'cofaigh
在过去的四十年中，北极海冰的显着减少和格陵兰冰盖（GIS）的冰量急剧减少与全球变暖和大气CO2的增加是一致的。在格陵兰东北部，自2000年以来，还观察到Nioghalvfjerdsbr（79 NG）和ZachariIsstrøm（ZI）出口冰川的重大质量损失，以及当地Norske Mer冰障（NKIB）的强烈季节性解体。为了更好地了解这些现代变化的驱动过程，古气候记录的研究是重要的，具有重大的社会意义。对直接在79NG前面回收的海洋沉积物岩心进行了包括有机地球化学和微体古生物学代理的多代理研究。从核心PS100/270的数据证明了强大的流入温暖的再循环大西洋水穿过东北格陵兰陆架从全新世早期之间的~10和7.5 ka。浮游植物生产力的整体高发生在一个稳定的海冰边缘制度，伴随着79NG撤退最有可能引发的峰值太阳辐射和当地海洋环流的变化。7.5ka时79NG底部的增强基底融化导致了冰架的完全解体。释放的淡水会驱动水柱分层，促进当地的陆固冰障，这是由降低生物标志物值和有孔虫丰度接近全新世早期结束的形成。近常年海冰条件下，夏季短，79 NG撤退到内峡湾，然后占主导地位，从~7.5到~0.8 ka。
During the past four decades significant decrease in Arctic sea ice and a dramatic ice mass loss of the Greenland Ice Sheet (GIS) has been coincident with global warming and an increase in atmospheric CO2. In Northeast Greenland significant mass loss from the outlet glaciers Nioghalvfjerdsbræ (79NG) and Zachariæ Isstrøm (ZI) and intensive seasonal breakup of the local Norske Øer Ice Barrier (NØIB) have also been observed since 2000. In order to better understand the processes driving these modern changes, studies of paleoclimate records are important and of major societal relevance. A multiproxy study including organic‐biogeochemical and micropaleontological proxies was carried out on a marine sediment core recovered directly in front of 79NG. Data from Core PS100/270 evidenced a strong inflow of warm recirculating Atlantic Water across the Northeast Greenland shelf from the early Holocene between ~10 and 7.5 ka. An overall high in phytoplankton productivity occurred within a stable sea ice margin regime, accompanied by 79NG retreat most probably triggered by peak solar insolation and changes in the local ocean circulation. Enhanced basal melt of the underside of 79NG at ~7.5 ka then led to the total disintegration of the ice shelf. The released freshwater would have driven water column stratification and promoted the formation of the local landfast ice barrier, which is shown by lowered biomarker values and foraminifera abundances toward the end of the early Holocene. Near perennial sea ice conditions with short summers and 79NG retreat to the inner fjord then prevailed from ~7.5 to ~0.8 ka.