基于数字图像的砾波纹表面沉积物形貌特征研究
Based on Digital Imaging Morphological Characteristics of Granule Ripple Surface Sediments

库姆塔格沙漠北部的三垄沙地区发育有典型的砾波纹，属于微风沙地貌形态。本研究以三垄沙地区典型砾波纹表面的粗颗粒为研究对象，借助数字图像处理技术，通过现场拍摄与室内图像处理相结合的方式，提取了砾波纹表面不同部位粗颗粒砾石的覆盖度、粒径、磨圆度、形状比率等参数，对其形貌特征进行了定量分析。结果表明，该区域砾波纹表面不同部位的粗颗粒砾石覆盖度介于27%~88%，以中等覆盖度为主；平均粒径介于1.40~2.19 mm，属于极粗沙到极细砾的范围，且分选性差异较大，不同部位粗颗粒的粒度频率曲线多呈窄至宽峰态分布。砾波纹表面不同部位粗颗粒的圆度均值介于0.68~0.75，形状比率变化范围为1.06~3.25，均值介于1.30~1.41，表明砾波纹表面的粗颗粒大多呈近椭圆或略呈长条状，以上研究结果可以为追溯戈壁物源区以及反演沉积物的搬运堆积过程提供有力参考。
The Sanlongsha area in the northern part of the Kumtagh Desert features typical granule ripples, which are a type of small aeolian bedform. This study focuses on the coarse grains on the surface of the typical gravel ripples in the Sanlongsha area. By combining field photography with indoor image processing using digital image processing techniques, we extracted parameters such as the coverage, grain size, roundness, and shape ratio of coarse gravel on different parts of the granule ripple surface, and conducted a quantitative analysis of their morphological characteristics. The results show that the coverage of coarse gravel on different parts of the granule ripple surface in this area ranges from 27% to 88%, with a predominance of moderate coverage. The average grain size ranges from 1.40 to 2.19 mm, falling within the range of very coarse sand to very fine gravel, and there is a significant difference in sorting. The grain size frequency curves of coarse grains in different parts mostly exhibit a distribution ranging from narrow to wide peaks. The average roundness of coarse grains on different parts of the gravel ripple surface ranges from 0.68 to 0.75, and the shape ratio varies from 1.06 to 3.25, with an average ranging from 1.30 to 1.41, indicating that the coarse grains on the gravel ripple surface are mostly nearly elliptical or slightly elongated. The research results can provide a solid reference for tracing the provenance of the Gobi and reconstructing the transportation and accumulation processes of sediments.