Seismic analyses of Cenozoic contourite drift development in the Northern Norwegian Sea
Seismic analyses of Cenozoic contourite drift development in the Northern Norwegian Sea
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挪威北部新生代等高线漂移发育的地震分析
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
P. Bryn
中科院分区：
文献类型：
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作者：
J. Laberg;T. Dahlgren;T. Vorren;H. Haflidason;P. Bryn
在挪威北方大陆边已查明四个漂流堆积物：罗弗敦漂流物、韦斯特哈伦漂流物、尼克漂流物和斯克林纳德朱佩特漂流物。根据地震特征，发现这些漂移主要属于两类：（1）隆起、拉长、上坡加积漂移（罗弗敦漂移、韦斯特伦漂移和尼克漂移），以及（2）充填漂移（Sklinnadjupet漂移）。这些冰碛位于大陆坡上。主要是表层水和中层水循环，与许多与底层水循环有关的北大西洋和南极漂流相反，沉积物的可用性控制了它们的增长。沉积物来源于大陆架和上斜坡的扬沙和大陆架上的冰盖。主要来源地是沃伦边缘。这就解释了附近尼克（1.2 m/ka）和Sklinnadjupet（0.5 m/ka）漂移的最大平均沉积速率高于远端罗弗敦（0.036 m/ka）和Vesterålen（0.060 m/ka）漂移的原因。高沉积速率的尼克漂移，晚Saalian和晚Weichselian之间的期间沉积的是相同的数量级，如以前报道的冰川最大期期间沉积的冰川斜坡沉积物。Sklinnadjupet漂移正在填充一个古滑动疤痕。由于存在可容纳空间，即充当沉积物圈闭的滑痕，因此有可能形成充填漂积。基于形成的底辟起源于Sklinnadjupet漂移沉积物，我们推断这些沉积物有一个泥质的组成，相对较高的含水量和低密度，更容易液化和动员相比，冰川diamictons。
Four drift accumulations have been identified on the continental margin of northern Norway; the Lofoten Drift, the Vesterålen Drift, the Nyk Drift and the Sklinnadjupet Drift. Based on seismic character these drifts were found to belong to two main groups; (1) mounded, elongated, upslope accretion drifts (Lofoten Drift, Vesterålen Drift and Nyk Drift), and (2) infilling drifts (Sklinnadjupet Drift). The drifts are located on the continental slope. Mainly surface and intermediate water circulation, contrary to many North Atlantic and Antarctic drifts that are related to bottom water circulation, and sediment availability have controlled their growth. Sediments were derived both from winnowing of the shelf and upper slope and from ice sheets when present on the shelf. The main source area was the Vøring margin. This explains the high maximum average sedimentation rate of the nearby Nyk (1.2 m/ka) and Sklinnadjupet (0.5 m/ka) Drifts compared with the distal Lofoten (0.036 m/ka) and Vesterålen (0.060 m/ka) Drifts. The high sedimentation rate of the Nyk Drift, deposited during the period between the late Saalian and the late Weichselian is of the same order of magnitude as previously reported for glacigenic slope sediments deposited during glacial maximum periods only. The Sklinnadjupet Drift is infilling a paleo-slide scar. The development of the infilling drift was possible due to the available accommodation space, a slide scar acting as a sediment trap. Based on the formation of diapirs originating from the Sklinnadjupet Drift sediments we infer these sediments to have a muddy composition with relatively high water content and low density, more easily liquefied and mobilised compared with the glacigenic diamictons.