A new bathymetry of the Northeast Greenland continental shelf: Constraints on glacial and other processes
A new bathymetry of the Northeast Greenland continental shelf: Constraints on glacial and other processes
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DOI：
10.1002/2015gc005931
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发表时间：
2015-10-01
影响因子：
3.5
通讯作者：
Evans, Jeffrey
中科院分区：
文献类型：
--
作者：
Arndt, Jan Erik;Jokat, Wilfried;Evans, Jeffrey
提出了格陵兰岛东北部 (NEG) 大陆架（北纬 74 度 - 北纬 81 度）的新数字测深模型 (DBM)。 DBM 的网格单元尺寸为 250 m x 250 m，包含来自 30 次多波束巡航、20 多次单波束巡航的测深数据以及来自工业地震线的第一反射器深度。与旧型号相比，新的 DBM 显着改善了测深效果。 DBM 不仅可以更好地描绘以前已知的海底形态，而且还揭示了以前未绘制的形态特征的存在，包括冰川衍生的槽、峡湾、接地区楔形物和侧碛石。这些海底地貌用于推断第四纪最后一个全冰期期间格陵兰冰盖的过去范围和冰流动态以及随后整个大陆架的冰退缩。 DBM揭示了跨陆架测深槽，可能使温暖的大西洋水团流入陆架，推动海洋终止的出口冰川的基础融化加速，将冰盖排泄到格陵兰岛东北部的海岸。中陆架上的小丘、水槽和丘状海底也被认为与盐底辟作用有关。确定了南北向的细长凹陷，可能与冰缘过程以及东格陵兰海流引起的侵蚀有关。已经发现了一个类似居约的山峰，并被解释为是在大约 55 Ma 前的一次火山活动中产生的。
A new digital bathymetric model (DBM) for the Northeast Greenland (NEG) continental shelf (74 degrees N-81 degrees N) is presented. The DBM has a grid cell size of 250 m x 250 m and incorporates bathymetric data from 30 multibeam cruises, more than 20 single-beam cruises and first reflector depths from industrial seismic lines. The new DBM substantially improves the bathymetry compared to older models. The DBM not only allows a better delineation of previously known seafloor morphology but, in addition, reveals the presence of previously unmapped morphological features including glacially derived troughs, fjords, grounding-zone wedges, and lateral moraines. These submarine landforms are used to infer the past extent and ice-flow dynamics of the Greenland Ice Sheet during the last full-glacial period of the Quaternary and subsequent ice retreat across the continental shelf. The DBM reveals cross-shelf bathymetric troughs that may enable the inflow of warm Atlantic water masses across the shelf, driving enhanced basal melting of the marine-terminating outlet glaciers draining the ice sheet to the coast in Northeast Greenland. Knolls, sinks, and hummocky seafloor on the middle shelf are also suggested to be related to salt diapirism. North-south-orientated elongate depressions are identified that probably relate to ice-marginal processes in combination with erosion caused by the East Greenland Current. A single guyot-like peak has been discovered and is interpreted to have been produced during a volcanic event approximately 55 Ma ago.