Using an erosion chamber, erodibility experiments on two different deep-sea sediments (mainly clayey silt) acquired in the western Pacific Ocean have been conducted to estimate the erosion rate and its potential controlling factors. Overall, the erosion rates of both deep-sea sediments were in the range of 10 −7 –10 −5 kg m −2 s −1 which was two or three orders of magnitude lower than that of sediments in shallow environments. Such erodibility, however, exhibited two contrasting patterns depending on the carbonate compensation depth (CCD), which determines carbonate contents in sediments. At one site (MC1), above the CCD, the sediments (carbonate content 18.32 ± 1.00 wt%) were easily resuspended by surface erosion, resulting in a high eroded mass (2.49 × 10 −2 kg m −2 at shear stress of 0.6 Pa). At another site (MC4), below the CCD, the sediments (carbonate content 0.06 ± 0.04 wt%) were less resuspended by floc erosion, resulting in a low eroded mass (3.70 × 10 −3 kg m −2 at shear stress of 0.6 Pa). Over the entire range of bed shear stress, the erosion rate above the CCD was about 1–6 times higher than that below the CCD. The difference in carbonate content between two sites caused different variations in the bed resistance with depth. The erodibility above the CCD was enhanced, probably due to the particle roughness and low bulk density. Once the bed shear stress exceeded about 0.39 Pa, the erosion type of MC1 shifted from depth-limited to transitional erosion. However, the erosion type of MC4 always remained depth-limited over the entire range of bed shear stress. These results underline the effect of calcium carbonate on resuspension and erosion behaviors of the deep-sea sediments.

中文翻译：

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碳酸钙颗粒的存在增强了深海沉积物的可蚀性

使用侵蚀室，对西太平洋获得的两种不同的深海沉积物（主要是粘土质淤泥）进行了可蚀性实验，以估计侵蚀速率及其潜在控制因素。总体而言，两种深海沉积物的侵蚀速率都在10 -7 –10 -5 kg m -2 s -1 的范围内，比浅层环境中的沉积物低两个或三个数量级。然而，这种可蚀性表现出两种截然不同的模式，这取决于碳酸盐补偿深度 (CCD)，它决定了沉积物中的碳酸盐含量。在 CCD 上方的一个地点（MC1），沉积物（碳酸盐含量 18.32 ± 1.00 wt%）很容易被表面侵蚀重新悬浮，导致高侵蚀质量（2.49 × 10 -2 kg m -2 剪切应力为 0.6帕）。在另一个站点 (MC4)，在 CCD 下方，沉积物（碳酸盐含量 0.06 ± 0.04 wt%）较少被絮体侵蚀重新悬浮，导致侵蚀质量低（3.70 × 10 -3 kg m -2 在 0.6 Pa 的剪应力下）。在整个床层剪应力范围内，CCD 上方的侵蚀速率比 CCD 下方的侵蚀速率高约 1-6 倍。两个地点之间碳酸盐含量的差异导致床层阻力随深度的不同变化。CCD 上方的可蚀性增强，可能是由于颗粒粗糙度和低堆积密度。一旦床层剪应力超过 0.39 Pa 左右，MC1 的侵蚀类型就会从深度限制转变为过渡侵蚀。然而，MC4 的侵蚀类型在整个床层剪切应力范围内始终保持深度限制。