Climatic and geomorphological mechanisms of rock art surface weathering in Helankou Gorge

The weathering of Paleolithic petroglyphs at Helankou Gorge, Ningxia, China, is a multifaceted process shaped by environmental factors. This study offers a quantitative assessment of dominant weathering mechanisms through long-term in-situ meteorological and rock temperature monitoring, geomorphological mapping, and laboratory analyses of rock samples. Results indicate that physical weathering, rather than chemical alteration, drives rock surface weathering. Thermal stress is the primary driver, with acute shock during summer rainfall-induced rapid cooling events (sun showers) generating stresses up to 6.40 MPa, exceeding sandstone tensile strength (5.20 MPa). Geomorphological conditions, including panel orientation, dip angle, and runoff exposure, create localized weathering hotspots. This framework informs targeted conservation strategies in arid rock art sites.