Basalt Columnar Jointing

The rocks of Lava Dam share a unique appearance, most of which has nearly hexagonal plane of fracture, and belongs to typical basalt columnar jointing. Columnar jointing is the cracks formed from homogeneous lava when it contracts evenly during cooling process, common to basalt. Between each two stone columns in column group, there is a perpendicular fissure almost penetrating through the upper and lower surface. When the top and bottom of lava flow contract at the same time, the jointing in the upper part divided column group into lower columnar jointed colonnade and upper entablature. There are lots of stones scattering at the bottom of Heilong Wall because the abundant joints and cracks in the lava of Heilong Wall led to the rock blocks to be unstable, collapse and fall.