...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Paleoceanography >Intermediate and deep water paleoceanography of the northern North Atlantic over the past 21,000 years
【24h】

Intermediate and deep water paleoceanography of the northern North Atlantic over the past 21,000 years

机译：过去21,000年北大西洋北部的中层和深水古海洋学

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Benthic foraminiferal stable isotope records from four high-resolution sediment cores, forming a depth transect between 1237 m and 2303 m on the South Iceland Rise, have been used to reconstruct intermediate and deep water paleoceanographic changes in the northern North Atlantic during the last 21 ka (spanning Termination I and the Holocene). Typically, a sampling resolution of –100 years is attained. Deglacial core chronologies are accurately tied to North Greenland Ice Core Project (NGRIP) ice core records through the correlation of tephra layers and changes in the percent abundance of Neogloboquadrina pachyderma (sinistral) with transitions in NGRIP. The evolution from the glacial mode of circulation to the present regime is punctuated by two periods with low benthic 6 13C and 6 180 values, which do not lie on glacial or Holocene water mass mixing lines. These periods correlate with the late Younger Dryas/Early Holocene (11.5-12.2 ka) and Heinrich Stadial 1 (14.7-16.8 ka) during which time freshwater input and sea-ice formation led to brine rejection both locally and as an overflow exported from the Nordic seas into the northern North Atlantic, as earlier reported by Meland et al. (2008). The export of brine with low 613C values from the Nordic seas complicates traditional interpretations of low ~13 C values during the deglaciation as incursions of southern sourced water, although the spatial extent of this brine is uncertain. The records also reveal that the onset of the Younger Dryas was accompanied by an abrupt and transient (-200-300 year duration) decrease in the ventilation of the northern North Atlantic. During the Holocene, Iceland-Scotland Overflow Water only reached its modern flow strength and/or depth over the South Iceland Rise by 7-8 ka, in parallel with surface ocean reorganizations and a cessation in deglacial meltwater input to the North Atlantic.
机译：来自四个高分辨率沉积物核心的底栖有孔虫稳定同位素记录，在南冰岛上升区形成了一个介于1237 m和2303 m之间的深度断面，已用于重建北大西洋北部最后21 ka的中古和深水古海洋学变化。 （跨越第I终端和全新世）。通常，可以达到–100年的采样分辨率。冰期年代学与北部格陵兰冰芯项目（NGRIP）的冰芯记录精确地联系在一起，这是通过底菲拉层的相关性以及NGRIP过渡带中新球藻的原始丰度百分比（正值）的变化来实现的。从冰川循环模式到目前状态的演变被两个底栖生物6 13C和6 180值较低的时期所打断，这两个时期不在冰川或全新世水质混合线上。这些时期与较年轻的德里亚斯/早全新世（11.5-12.2 ka）和Heinrich Stadial 1（14.7-16.8 ka）有关，在此期间，淡水输入和海冰的形成不仅导致了当地的盐水排泄，而且还导致了淡水的溢出。根据梅兰德等人先前的报道，北欧海进入北大西洋北部。 （2008）。从北欧海出口613C值较低的盐水会使冰消融化过程中对〜13 C值较低的传统解释变得复杂，这是南部来源水的入侵，尽管这种盐水的空间范围尚不确定。记录还显示，北大西洋北部的通风异常并伴随着短暂而短暂的（-200-300年持续时间）减少，而出现了年轻的树蛙。在全新世期间，冰岛-苏格兰溢流水仅在南冰岛上升区达到7-8 ka的现代流动强度和/或深度，与此同时，表层海洋重组和向北大西洋的冰河融水输入也停止了。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号