LATE WEICHSELIAN SUBMARINE DEBRIS FLOW DEPOSITS ON THE BEAR-ISLAND-TROUGH-MOUTH-FAN
LATE WEICHSELIAN SUBMARINE DEBRIS FLOW DEPOSITS ON THE BEAR-ISLAND-TROUGH-MOUTH-FAN
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DOI：
10.1016/0025-3227(95)00055-4
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发表时间：
1995-09-01
期刊：
影响因子：
2.9
通讯作者：
VORREN, TO
中科院分区：
文献类型：
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作者：
LABERG, JS;VORREN, TO
利用高分辨率反射地震和重力岩心研究了熊岛海槽口扇末次冰期的沉积过程。扇体序列主要由宽达24 km、厚达50 m的大型泥石流沉积物组成。在100 km的下坡处，可以跟踪到碎屑瓣，最大的面积为1880 km（2）。当巴伦支海冰盖到达大陆架断裂时，产生了大型泥石流。冰川沉积物搬运到地面线暂时存储在上斜坡。由于沉积速率高，沉积物不稳定，地震、过陡和/或超孔隙压力的积聚引发沉积物释放，产生大的碎片流。沉积物也被侵蚀，并纳入在下坡如何。泥石流是最重要的沉积物分布过程，这是由于冰川形成的杂岩具有较高的剪切强度、较低的流动性和较低的扇体坡度。该扇的Weichselian演化的特点是在Weichselian早期和中期沉积速率相对较低。巴伦支海冰盖可能在Weichselian晚期两次达到大陆架断裂。在末次盛冰期，平均每35至75年释放一次大型泥石流，包括18 km（3）的沉积物。
Sedimentary processes on the Bear Island Trough Mouth Fan during the last glacial were studied using high resolution reflection seismics and gravity cores. The fan succession is dominated by large debris flow deposits of up to 24 km in width and 50 m thick. Debris lobes can be followed over 100 km downslope and the largest cover an area of 1880 km(2). The large debris flows were generated when the Barents Sea Ice Sheet reached the shelf break. Glacigenic sediments transported to the grounding-line were temporarily stored on the upper slope. Due to the high sedimentation rate, the sediments were unstable and earthquakes, oversteepening and/or build up of excess pore pressure triggered sediment release generating large debris hows. Sediments were also eroded and incorporated during the downslope how. Debris flows were the most important sediment distributing process due to the relatively high shear strength, low flow mobility of the glacigenic diamicton, and the low fan gradient. The Weichselian evolution of the fan was characterized by a relatively low sedimentation rate during the Early and Mid Weichselian. The Barents Sea Ice Sheet might have reached the shelf break twice during the Late Weichselian. On average one large debris flow, comprising 18 km(3) of sediments, was released between every 35 to 75 years during the last glacial maximum.