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首页> 外文期刊>Journal of geophysical research. Earth Surface: JGR >Sediment dynamics in paired High Arctic lakes revealed from high-resolution swath bathymetry and acoustic stratigraphy surveys
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Sediment dynamics in paired High Arctic lakes revealed from high-resolution swath bathymetry and acoustic stratigraphy surveys

机译：高分辨率条带测深法和声学地层学调查揭示了成对的北极高地湖泊的沉积动力学

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摘要

High Arctic lakes are commonly used for paleoclimatic reconstructions because they are particularly sensitive to climate variability. However, the processes leading to sediment deposition and distribution in these lakes are often poorly understood. Here for the first time in the Canadian High Arctic, we present original data resulting from swath bathymetry and subbottom surveys carried out on two lakes at Cape Bounty, Melville Island. The results reveal the dynamic nature of the lakes, in which mass movement deposits and bedforms on the deltas reflect frequent slope instabilities and hyperpycnal flow activity. The analysis of the mass movement deposits reveals that small blocky debris flows/avalanches, debris flows, and a slide occurred during the Holocene. These mass movements are believed to have been triggered by earthquakes and potentially by permafrost thawing along the shoreline. Altogether, these mass movement deposits cover more than 30% of the lake floors. Additionally, the river deltas on both lakes were mapped and reveal the presence of several gullies and bedforms. The presence of gullies along the delta front indicates that hyperpycnal flows generated at the river mouth can transport sediment in different trajectories downslope, resulting in a different sediment accumulation pattern and record. The dynamic nature of these two lakes suggests that further analysis on sedimnt transport and distribution within Arctic lakes is required in order to improve paleoclimatic reconstructions.
机译：高北极湖通常用于古气候重建，因为它们对气候变化特别敏感。但是，导致沉积物在这些湖泊中沉积和分布的过程通常知之甚少。在加拿大高北极圈中，我们首次在此展示了在梅尔维尔岛博恩蒂角的两个湖上进行的条带测深法和底下勘测产生的原始数据。研究结果揭示了湖泊的动态性质，其中三角洲上的质量运动沉积物和床形反映了频繁的边坡失稳和高温流活动。对整体运动沉积物的分析表明，在全新世期间发生了小的块状碎屑流/崩塌，碎屑流和滑动。据认为，这些大规模运动是由地震以及沿海岸线冻土融化引发的。这些大规模的运动沉积物总共覆盖了湖底的30％以上。此外，还绘制了两个湖泊的河三角洲，并揭示了一些沟壑和床形的存在。沿三角洲前缘的沟壑的存在表明，在河口处产生的高温流可以沿不同的轨迹下坡输送沉积物，从而导致不同的沉积物沉积方式和记录。这两个湖泊的动态性质表明，需要进一步分析北极湖泊内的沉积物运输和分布，以改善古气候重建。

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