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Holocene paleoceanography of the Northeast Greenland shelf
Climate of the Past ( IF 3.8 ) Pub Date : 2021-06-02 , DOI: 10.5194/cp-2021-59
Teodora Pados-Dibattista , Christof Pearce , Henrieka Detlef , Jørgen Brendtsen , Marit-Solveig Seidenkrantz

Abstract. The Northeast Greenland shelf is highly sensitive to climate and ocean variability because it is swept by the East Greenland Current, which, through the western Fram Strait, forms the main pathway of export of sea ice and cold water masses from the Arctic Ocean into the North Atlantic Ocean. We carried out benthic foraminiferal assemblage, stable isotope- and sedimentological analyses of a marine sediment core retrieved from the Northeast Greenland shelf (core DA17-NG-ST7-73), which provided a multiproxy reconstruction of Holocene paleoceanographic conditions. The results reveal significant variations in the water masses and thus, in the strength of the East Greenland Current over the last ca. 9.4 ka BP. Between 9.4 and 8.2 ka BP the water column off Northeast Greenland was highly stratified, with cold, sea ice-loaded surface waters and strong influx of warm Atlantic Water in the subsurface. At ~8.4 ka BP a short-lived peak in terrestrial elements may be linked to influx of ice-berg transported sediments and thus, to the so-called 8.2 ka event. Holocene Thermal Maximum like conditions prevailed from 8.2 to 6.2 ka BP, with a strong influence of the Return Atlantic Current and a weakened transport of Polar Water in the upper East Greenland Current. After 6.2 ka BP we recorded a return to a more stratified water column with sea-ice loaded surface waters and still Atlantic-sourced subsurface waters. After 4.2 ka BP increased Polar Water at the surface of the East Greenland Current and reduction of the Return Atlantic Water at subsurface levels led to freshening and reduced stratification of the water column and (near) perennial sea-ice cover. The Neoglaciation started at 3.2 ka BP at our location, characterized by a strengthened East Greenland Current. Cold subsurface water conditions with possible sea-ice cover and minimum surface water productivity persisted here throughout the last ~3 kyr.

中文翻译:

东北格陵兰大陆架全新世古海洋学

摘要。格陵兰东北陆架对气候和海洋变率高度敏感,因为它被东格陵兰洋流席卷,东格陵兰洋流穿过西弗拉姆海峡,形成了海冰和冷水团从北冰洋向北方输出的主要通道大西洋。我们对从东北格陵兰大陆架(核心 DA17-NG-ST7-73)取回的海洋沉积物核心进行了底栖有孔虫组合、稳定同位素和沉积学分析,这提供了全新世古海洋条件的多代理重建。结果揭示了水团的显着变化,因此,东格陵兰洋流的强度在过去大约 10 年间发生了显着变化。9.4 ka BP。在 9.4 到 8.2 ka BP 之间,格陵兰岛东北部的水体高度分层,冷、海冰覆盖的地表水和地下温暖大西洋水的大量涌入。在~8.4 ka BP,陆地元素的短暂峰值可能与冰山输送沉积物的流入有关,因此与所谓的8.2 ka 事件有关。在 8.2 至 6.2 ka BP 期间,全新世热最大值类似条件普遍存在,受到大西洋回流的强烈影响和东格陵兰海流上游极地水的输送减弱。在 6.2 ka BP 之后,我们记录到一个更分层的水柱,海冰加载的地表水和仍然来自大西洋的地下水。在 4.2 ka BP 之后,东格陵兰洋流表面的极地水增加,而亚表层的大西洋回流水减少,导致水柱和(近)常年海冰覆盖层变新鲜和分层减少。我们所在地的新冰期开始于 3.2 ka BP,其特征是东格陵兰海流加强。在过去的约 3 kyr 中,可能有海冰覆盖和最低地表水生产力的寒冷的地下水条件在这里持续存在。
更新日期:2021-06-02
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