The geoheritage of Yandangshan is a formation and evolution representation of revived caldera in the Asian continent margin of the late Mesozoic Era. It recorded the complete geological evolution process, including eruption, collapse, regrowth and uplifting of the volcanoes in Yandangshan, forming an ideal 3D model, a field study and outdoor research laboratory for Mesozoic Cretaceous caldera.

Uplifting followed the formation of the Yandangshan Caldera in 100 million years ago. When sea level rose in the Quaternary, the water only reached to its outer valleys. The caldera transformed mainly by cutting and uplift along fractures. Quartz syenites were formed by intrusion and later appeared on ground due to erosion. Valleys developed around the ring and along radiated fractures. Lithologic sequences and tectonic sections of the caldera were therefore exposed by the power of Nature, revealing the internal structure of the Cretaceous caldera, especially its relationship between the caldera root and tectonic elements and rocks of the caldera root. It also revealed the interaction between eruption products and the intrusion, recording the whole process of from early acid magma evolution and intrusion to cooling and crystallization. The record has important scientific value for studying the formation and magmatism of Cretaceous caldera.