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Continental slope and rise geomorphology seaward of the Totten Glacier, East Antarctica (112°E-122°E)
Marine Geology ( IF 2.6 ) Pub Date : 2020-05-20 , DOI: 10.1016/j.margeo.2020.106221
P.E. O'Brien , A.L. Post , S. Edwards , T. Martin , A. Caburlotto , F. Donda , G. Leitchenkov , R. Romeo , M. Duffy , D. Evangelinos , L. Holder , A. Leventer , A. López-Quirós , B.N. Opdyke , L.K. Armand

The continental slope and rise seaward of the Totten Glacier and the Sabrina Coast, East Antarctica features continental margin depositional systems with high sediment input and consistent along-slope current activity. Understanding their genesis is a necessary step in interpreting the paleoenvironmental records they contain. Geomorphic mapping using a systematic multibeam survey shows variations in the roles of downslope and along slope sediment transport influenced by broad-scale topography and oceanography. The study area contains two areas with distinct geomorphology. Canyons in the eastern part of the area have concave thalwegs, are linked to the shelf edge and upper slope and show signs of erosion and deposition along their beds suggesting cycles of activity controlled by climate cycles. Ridges between these canyons are asymmetric with crests close to the west bank of adjacent canyons and are mostly formed by westward advection of fine sediment lofted from turbidity currents and deposition of hemipelagic sediment. They can be thought of as giant levee deposits. The ridges in the western part of the area have more gently sloping eastern flanks and rise to shallower depths than those in the east. The major canyon in the western part of the area is unusual in having a convex thalweg; it is likely fed predominantly by mass movement from the flanks of the adjacent ridges with less sediment input from the shelf edge. The western ridges formed by accretion of suspended sediment moving along the margin as a broad plume in response to local oceanography supplemented with detritus originating from the Totten Glacier. This contrasts with interpretations of similar ridges described from other parts of Antarctica which emphasise sediment input from canyons immediately up-current. The overall geomorphology of the Sabrina Coast slope is part of a continuum of mixed contourite-turbidite systems identified on glaciated margins.



中文翻译:

南极东部托特冰川的大陆坡和上升地貌向海(112°E-122°E)

南极东部Totten冰川和Sabrina海岸的大陆坡和上升海,具有大陆边缘沉积系统,具有高的泥沙输入量和一致的沿斜坡电流活动。了解它们的起源是解释它们包含的古环境记录的必要步骤。使用系统的多波束调查进行的地貌制图表明,受大规模地形和海洋学的影响,下坡的作用和沿斜坡沉积物传输的变化。研究区域包含两个具有不同地貌的区域。该地区东部的峡谷凹凹的thalwegs,与陆架边缘和上斜坡相连,并在其床层显示出侵蚀和沉积的迹象,表明活动周期受气候周期控制。这些峡谷之间的山脊是不对称的,其波峰靠近相邻峡谷的西岸,并且大部分是由浊流和沉积的半沉积物向西平流形成的。他们可以被认为是巨大的堤防存款。该地区西部的山脊比东部的山脊倾斜得更缓和,并且上升到更浅的深度。该地区西部的主要峡谷不寻常,有一个凸起的海藻。它可能主要是由于来自相邻山脊侧面的质量运动而获得的,而来自架缘的泥沙输入较少。西部山脊是由于响应当地海洋学并补充了来自托特冰川的碎屑而沿边缘运动成宽羽状的悬浮沉积物而形成的。这与南极洲其他地区描述的类似山脊的解释形成对比,后者强调了从峡谷中立即向上流输入的沉积物。萨布丽娜海岸斜坡的整体地貌是在冰缘上识别出的混合轮廓石-浊积体系统的连续体的一部分。

更新日期:2020-05-20
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