Two sets of joints are deve- loped in the granite through a long-term physical and che- mical weathering.The cave is becoming larger through gra- nite collapse under the gravity.

• 花岗岩发育两组不同方向的节理，在长期的物理风化和化学风化及重力等作用下，洞内不断倒塌扩大，而形成现今的洞穴形态。