<b>Self-healing</b><b> mineral film</b><b>on</b><b> sandstone</b><b>: </b><b>a</b><b>natural passive sampler</b>

Despite experiencing thousands of years of wind and rain, some stone carvings have remained remarkably well-preserved. Understanding the information recorded is of great significance for reconstructing the level of anthropogenic pollution in the environment in the past. Here, a black to reddish-brown, relatively dense mineral film with a thickness of approximately 150 μm was observed on the surface of sandstone.尽管历经数千年的风雨侵蚀，部分石刻仍保存得相当完好。解析其所记录的信息，对于复原过去环境中的人为污染水平具有重要意义。本次研究在砂岩表面观察到一层呈黑色至红棕色、质地相对致密的矿物膜，其厚度约为150微米。