Extreme sediment and ice discharge from marine-based ice streams: New evidence from the North Sea
Extreme sediment and ice discharge from marine-based ice streams: New evidence from the North Sea
复制标题
海洋冰流的极端沉积物和冰排放：来自北海的新证据
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
G. Bigg
中科院分区：
文献类型：
--
作者：
A. Nygård;H. Sejrup;H. Haflidason;W. Lekens;C. Clark;G. Bigg
了解冰流动力学的一个主要问题是缺乏关于冰流寿命和沉积物输运效率的精确数据。在这里，我们提出了第一个良好的约束数据从古冰流的沉积物通量。这已经实现了通过计算沉积物的体积位于挪威海峡冰流的出口处的风扇上的泥石流，并转换为通量测量占流在这一幕的持续时间（20和19万年之间的末次冰期）。在这一时期，冰流平均每年输送1.1 Gt的沉积物，相当于冰流前缘每米宽度8000 m3/年。计算出的通量是一个数量级高于大多数以前的估计，其他古冰流，并与目前的沉积物通量从世界上最大的河流。碎屑流沉积的短时间表明，挪威海峡冰流经历了快速的开关切换，因此，间断的冰山输送到北大西洋。
A major problem for understanding the dynamics of ice streams has been a lack of precise data on ice streaming longevity and sediment transport efficacy. Here we present the first well-constrained data on sediment flux from a paleoice stream. This has been achieved by computing the volume of sediment deposited as debris flows on the fan located at the outlet of the Norwegian Channel ice stream, and converting to a flux measurement by accounting for the duration of streaming in this episode (between 20 and 19 ka during the last glacial stage). In this period the ice stream delivered an average 1.1 Gt of sediment per year, equivalent to 8000 m 3 yr −1 per meter width of ice stream front. The calculated flux is an order of magnitude higher than most previous estimates for other paleoice streams and is comparable to the present sediment flux from the world9s largest rivers. The short period of debris-flow deposition suggests that the Norwegian Channel ice stream underwent rapid on-off switching, with punctuated iceberg delivery to the North Atlantic as a consequence.