The origin of massive diamicton facies by iceberg rafting and scouring, Scoresby Sund, East Greenland
The origin of massive diamicton facies by iceberg rafting and scouring, Scoresby Sund, East Greenland
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冰山漂流和冲刷造成的块状重聚岩相的起源，东格陵兰斯科斯比湾
DOI：
10.1111/j.1365-3091.1994.tb01390.x
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发表时间：
1994
期刊：
影响因子：
3.5
通讯作者：
P. Marienfeld
中科院分区：
文献类型：
--
作者：
J. Dowdeswell;R. Whittington;P. Marienfeld
在Scoresby Sund和邻近的东格陵兰陆架发现的39米岩心物质中，近90%是大直径物质，据解释，主要是由冰山漂流碎片的释放和冰山冲刷的重新加工形成的。还可能有来自冰河来源的罚款的暂停结算的贡献。模型计算表明，14C在Scoresby Sund的全新世沉积速率为0.1m-0.3m1000yr−1，这主要是由冰山碎屑漂流造成的。另外4%的岩心材料是砾石或粗沙透镜，解释为反映了冰山倾倒的碎屑。在Scoresby Sund Ford系统及其邻近的东格陵兰陆架(69-72°N和75°N)超过3万平方公里的声学记录中，观测到密集的冰山冲刷，使海底沉积物重新工作。格陵兰冰盖出口冰川产生冰山的速度和冰架上的冰山漂移轨迹表明，冰山漂流和冲刷可能在陆架断裂上方50万平方公里的相当大一部分区域内发挥着重要作用。冰山漂流和冲刷形成的块状直径岩的现代产状相对广泛，加上细粉的悬浮沉降，表明它也可能是受冰川影响的地质记录中的一个重要相。上述块状直径相地质记录的识别也可能表明以前存在快速流动的冰盖出口冰川。
Almost 90% of 39 m of core material recovered from Scoresby Sund and the adjacent East Greenland shelf is massive diamicton, interpreted to be formed predominantly by the release of iceberg rafted debris and reworking by iceberg scouring. There is also likely to be a contribution from suspension settling of fines derived from glaciofluvial sources. Model calculations suggest that the 14C derived Holocene sedimentation rate of 0.1-0.3 m 1000 yr−1 in Scoresby Sund can be accounted for mainly by iceberg rafting of debris. A further 4% of core material is of gravel or coarse sand lenses, interpreted to reflect iceberg dumping of debris. Intensive iceberg scouring, which reworks sea floor sediments, is observed on acoustic records from over 30 000 km2 of the Scoresby Sund fiord system and the adjacent East Greenland shelf (69-72°N and 75°N). The rate of iceberg production from Greenland Ice Sheet outlet glaciers, and iceberg drift tracks on the shelf, suggests that iceberg rafting and scouring may be important over a significant proportion of the 500 000 km2 area above the shelf break. The relatively extensive modern occurrence of massive diamicton, formed by iceberg rafting and scouring, together with suspension settling of fines, suggests that it may also be a significant facies in the glacier-influenced geological record. The recognition in the geological record of the massive diamicton facies described above may also indicate the former presence of fast flowing ice sheet outlet glaciers.