Science. 1988 Jan 29;239(4839):471-6. doi: 10.1126/science.239.4839.471.
Cooling-induced fractures, also known as columnar joints, divide basaltic lava flows into prismatic columns with polygonal cross sections. The regularity and symmetry of the fracture patterns have long fascinated naturalists. In view of the recent selection of two candidate nuclear waste sites in areas where polygonally fractured volcanic rocks are located, a better understanding of the fracture patterns is required. Field data indicate that the tetragonal networks at flow surfaces evolve systematically to hexagonal networks as the joints grow inward during solidification of lava. This evolution occurs by the gradual change of most orthogonal intersections to nonorthogonal intersections of about 120 degrees. The surface features and intersection geometries of columnar joints show that joint segments at any given level form sequentially yet harmoniously.
冷却引发的裂缝，也被称为柱状节理，将玄武岩熔岩流分割成具有多边形横截面的棱柱体。这些裂缝模式的规律性和对称性长期以来一直吸引着自然主义者。鉴于最近在多边形断裂火山岩所在的地区选择了两个候选核废料场，因此需要更好地了解这些裂缝模式。实地数据表明，在熔岩凝固过程中，随着节理向内部生长，流面的四边形网络会系统地演化为六边形网络。这种演化是通过大多数正交交点逐渐变为约 120 度的非正交交点来实现的。柱状节理的表面特征和交点几何形状表明，任何给定水平的节理段都是按顺序但和谐地形成的。
