columnar jointing

columnar jointing

[kə′ləm·nər ′jȯint·iŋ]
(geology)
Parallel, prismatic columns that are formed as a result of contraction during cooling in basaltic flow and other extrusive and intrusive rocks. Also known as columnar structure; prismatic jointing; prismatic structure.
References in periodicals archive ?
These are examples of columnar jointing, solid rock divided into prismatic columns by contraction as the lava flow solidified (Devil's Postpile is the greatest example in the West).
Photo: Fractured block of basalt lava along Burton Creek trail shows columnar jointing