IMPRINTS IN SILICA GRAINS INDUCED DURING AN OPEN-CHANNEL FLOW EXPERIMENT: DETERMINATION OF MICROTEXTURAL SIGNATURES DURING AQUEOUS TRANSPORT
IMPRINTS IN SILICA GRAINS INDUCED DURING AN OPEN-CHANNEL FLOW EXPERIMENT: DETERMINATION OF MICROTEXTURAL SIGNATURES DURING AQUEOUS TRANSPORT
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DOI：
10.2110/jsr.2017.39
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发表时间：
2017-07-01
影响因子：
2
通讯作者：
Dawson, Sue
中科院分区：
文献类型：
--
作者：
Costa, Pedro J. M.;Park, Yong Sung;Dawson, Sue
这项工作的目的是识别和表征在不同流速、不同沉积物浓度、不同运输距离和时间间隔的水运输过程中产生的二氧化硅玻璃颗粒（类似于石英）的微结构特征。为了实现这一目标，研究人员在不同条件下进行了一项明渠流动实验，包括流速（0.67至1.4 m/s）、持续时间（1或10分钟）、距离（0至2.5 m）和沉积物浓度（60%或80%）。实验条件用于复制自然现象，如河流浅层流速或海岸冲刷过程。在实验之前，对微球表面进行了成像，并清除了任何微纹理印记。随着流速、距离和沉积物浓度的增加，表面上大量覆盖着机械成因的微纹理（即陨石坑、磨损痕迹和v形撞击痕迹）的数量也会增加。对二氧化硅的SEM显微照片进行了分析和分类，以提供在明渠流动实验中产生的特定微结构的例子。实验的目的是表征石英颗粒的表面微观特征，模拟海岸和河流环境的水动力条件。结果表明，在分析的颗粒中，较高的流速（和较高的沉积物浓度）与较大的微结构机械印记之间存在很强的相关性，从而表明微结构印记与水流模式之间存在明确的关系。这些结果对未来分析颗粒印记及其与沉积物输运类型的关系的微结构工作具有重要意义。这里展示的一个例子是，较高的v型标志可以用作超临界流动条件的指标。
The aim of this work is to identify and characterize microtextural signatures in silica glass grains (used as analogous to quartz) that are produced during aqueous transport at different flow velocities, with variable sediment concentrations, transport distances, and time intervals. To achieve this, an open-channel flow experiment was conducted with a mixture of sand and silica glass microspheres in varying conditions-velocity (from 0.67 to 1.4 m/s), duration (1 or 10 minutes), distance (0 to 2.5 m) and sediment concentration (60 or 80%). Experimental conditions were used to replicate natural phenomena such as river superficial velocity or coastal swash processes.Before the experiment the microsphere surfaces were imaged and clear of any microtextural imprint. Increasing velocity, distance, and sediment concentration exhibited a strong correlation with higher numbers of surfaces abundantly covered with microtextures of mechanical origin (i.e., craters, abrasion marks, and v-shaped percussion marks). SEM microphotographs of silica were analyzed and classified to provide examples of the specific microtextures produced during the open-channel flow experiment.The purpose of the experiment was to characterize surface microscopic signatures in quartz grains replicating hydrodynamic conditions of coastal and fluvial environments. The results demonstrated a strong correlation between higher velocities (and higher sediment concentrations) and a larger presence of microtextural mechanical imprints in the grains analyzed, thus demonstrating a clear relation between microtextural imprints and water flow modes. These results have important implications for future microtextural works analyzing grain imprints and their relation to sediment transport types. An example demonstrated here is that the higher presence of v-marks could be used as an indicator of supercritical flow conditions.