Abstract

A summary seismostratigraphic description of the Nansen Basin sedimentary cover was compiled using data from the Norwegian sector of the Eurasian Basin and data interpretation from the Russian Arktika-2011 project. It was found that sea level fluctuations had a significant impact on sedimentation processes in the Arctic basin. Erosion processes on the shelf and slope were developed during regression phases. In the deep-water part, these processes were accompanied by the formation of fan systems, contourites, and slump bodies in both Neogene–Quaternary and older seismic sequences in the Nansen Basin. They are confined to the modern outer fan distinguished in the bottom topography in both young and older seismic sequences. The sedimentary infill was transported through the Franz Victoria and St. Anna troughs, which already existed at the beginning of the Eurasian Basin opening. The distal parts of the fans form extended sedimentary bodies in the basin with a loss of coherence and acoustic blanking of the seismic record. The contourites are distinguished in all sections near the continental foothill, and slump bodies occur on the slope near the shelf edge. Miocene–Pliocene sequences contain gravity flow sediments located more than 100 km away from the modern fan boundary. The sedimentary infill of the Nansen Basin was regulated both by the intensity of sediment influx and by changes in the hydrological regime of the basin associated with the periods of its isolation from the World Ocean and transition to a single water circulation system. The accumulation of contourite sediments began in the Miocene. They are developed near continental foothills together with fan lobes, and it is not possible to separate these sedimentary body types. The sharpest sea level fall at the Pliocene–Quaternary boundary resulted in the intense sediment input and the formation of spacious zones of coherence loss in the distal fan parts of the basin. The occurrence and spatial distribution of contourite and gravity flow deposits in the basin correlate with sea level fluctuations in antiphase with intense erosion on the Barents Sea shelf, which also depend on vertical movements in the basin surrounding (Svalbard and Franz-Joseph Land archipelagos). Seismic profiles without superimposed interpretation are given in the electronic supplementary materials.

中文翻译：

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南森盆地南部古近系—第四系多相沉积系统

摘要

使用来自欧亚盆地挪威部分的数据和来自俄罗斯 Arktika-2011 项目的数据解释，对南森盆地沉积盖层的地震地层描述进行了汇总。研究发现，海平面波动对北极盆地的沉积过程有显着影响。陆架和斜坡上的侵蚀过程是在回归阶段发展起来的。在深水部分，这些过程伴随着南森盆地新近系-第四纪和老地震序列中扇系、等高岩和塌陷体的形成。它们仅限于在年轻和较老的地震序列中以底部地形区分的现代外扇。沉积填充物通过弗朗茨维多利亚和圣安娜海槽运输，早在欧亚盆地开放之初就已经存在。扇的远端部分在盆地中形成扩展的沉积体，地震记录的相干性和声学消隐丧失。大陆山麓附近各断面等高岩特征明显，陆架边缘附近斜坡上有滑塌体。中新世-上新世层序包含距现代扇边界 100 多公里的重力流沉积物。南森盆地的沉积充填受到沉积物流入强度和盆地水文状况变化的调节，这些变化与其与世界海洋隔绝并过渡到单一水循环系统的时期有关。等高岩沉积物的积累始于中新世。它们与扇叶一起发育在大陆山麓附近，不可能将这些沉积体类型分开。上新世-第四纪边界处海平面下降幅度最大，导致沉积物输入强烈，并在盆地远端扇形部分形成了宽敞的相干损失区。盆地中等高岩和重力流沉积物的发生和空间分布与巴伦支海陆架强烈侵蚀的反相海平面波动有关，这也取决于盆地周围（斯瓦尔巴群岛和弗朗茨-约瑟夫地群岛）的垂直运动。没有叠加解释的地震剖面在电子补充材料中给出。上新世-第四纪边界处海平面下降幅度最大，导致沉积物输入强烈，并在盆地远端扇形部分形成了宽敞的相干损失区。盆地中等高岩和重力流沉积物的发生和空间分布与巴伦支海陆架强烈侵蚀的反相海平面波动有关，这也取决于盆地周围（斯瓦尔巴群岛和弗朗茨-约瑟夫地群岛）的垂直运动。没有叠加解释的地震剖面在电子补充材料中给出。上新世-第四纪边界处海平面下降幅度最大，导致沉积物输入强烈，并在盆地远端扇形部分形成了宽敞的相干损失区。盆地中等高岩和重力流沉积物的发生和空间分布与巴伦支海陆架强烈侵蚀的反相海平面波动有关，这也取决于盆地周围（斯瓦尔巴群岛和弗朗茨-约瑟夫地群岛）的垂直运动。没有叠加解释的地震剖面在电子补充材料中给出。盆地中等高岩和重力流沉积物的发生和空间分布与巴伦支海架上强烈侵蚀的反相海平面波动有关，这也取决于盆地周围（斯瓦尔巴群岛和弗朗茨-约瑟夫地群岛）的垂直运动。没有叠加解释的地震剖面在电子补充材料中给出。盆地中等高岩和重力流沉积物的发生和空间分布与巴伦支海陆架强烈侵蚀的反相海平面波动有关，这也取决于盆地周围（斯瓦尔巴群岛和弗朗茨-约瑟夫地群岛）的垂直运动。没有叠加解释的地震剖面在电子补充材料中给出。