Erosion refers to the geological process in which external forces such as running water, wind, glaciers and ocean waves break down surface bedrock and transport the resulting clastic sediments to other locations. As one of the dominant exogenous processes shaping the Earth’s landforms, it constitutes a vital component of the rock cycle and serves as the primary formative agent for most landform landscapes featured in geoparks.

Erosion is categorized into five major types: fluvial erosion, aeolian erosion, glacial erosion, marine erosion and chemical karst corrosion. Fluvial erosion is widespread and intensive: rainfall scours the ground surface, while running water widens and deepens river channels and valley bottoms; surface runoff strips away hillslope materials, fragmenting land to carve out canyons and river valleys. Subsurface groundwater chemically dissolves limestone to develop karst landforms. In arid regions, aeolian erosion yields yardang landforms and wind-eroded mushrooms; combined with wind transportation, it generates gobi deserts, whereas bare-rock deserts originate from intensive wind erosion coupled with weathering and episodic fluvial activity. Glacial erosion produces horn peaks and U-shaped valleys, and marine erosion gives rise to sea cliffs and sea stacks.

Beyond sculpting distinctive landscapes, erosion supplies sediment precursors for sedimentary rock formation. It functions as a key geological linkage connecting the lithosphere, hydrosphere, atmosphere and biosphere, bearing great significance for ecological conservation, land resource management and the preservation of geoheritage sites.