Erosion rates of yardang landforms downstream of the Peacock River, NW China
摘要
Yardang landforms are important research objects in the fields of climate change, geomorphological evolution, aeolian sand management, and ecosystem stability. The Lop Nur area, where the term “Yardang” originated, has witnessed limited in-depth studies of its Yardang landform development and evolution. Here, we integrate field surveys of Yardang landforms downstream of the Peacock River with 14C dating, optical stimulated luminescence dating (OSL), large-scale topographic mapping, and three-dimensional (3-D) laser scanning to investigate the erosion rates of these landforms. Our key findings are as follows: (1) We systematically determined the deposition, exposure, and erosion times related to Yardang development downstream of the Peacock River; these were 2800 ± 300, 1900, and 565 ± 25 a BP, respectively. (2) Since 565 ± 25 a BP, the average erosion rate of Yardang landforms downstream of the Peacock River has ranged from 0 to 1.54 cm/a, with 88.32% of the area experiencing rates between 0.55 and 1.37 cm/a. Currently, 72% of the area is eroding at rates ranging from 0 to 3.0 cm/a, with 17.30% of that area experiencing rates of 0.6‒1.2 cm/a, and 38.70% experiencing rates of < 0.6 cm/a. The current erosion rates are substantially lower than historical averages, with some low-lying areas currently accumulating sediment. (3) We have established a comprehensive research method for the determination of erosion rates; this is based on the developmental patterns of Yardang landforms for historical average erosion rates, and on 3-D laser scanning for current erosion rates, allowing us to determine both the historical average and current erosion rates of Yardang landforms downstream of the Peacock River. The establishment of a permanent erosion monitoring network in this area will support the long-term tracking and monitoring of Yardang landform development and provide a foundation for research on climate change, geomorphological evolution, aeolian sand management, and ecosystem stability in the region. These findings are crucial in understanding the evolution of Yardang landforms in this region and will facilitate the advancement of numerical simulations aiding long-term geomorphological evolution research. Our study provides insights into the timing of Yardang landform development as well as historical and current erosion rates; it also establishes a comprehensive research methodology, which is essential for quantitative research on the formation and development environment of Yardang landforms downstream of the Peacock River.