Definition of columnar structure
i. A mineral fabric consisting of slender crystals of prismatic cross section, as in some amphiboles.
ii. See: columnar jointing
iii. Columns, 9 to 14 cm in diameter and 1 to 1.4 m in length, found in some calcareous shales or argillaceous limestones; oval to polygonal in section. Columns are perpendicular to bedding. Possibly a desiccation structure.
Ref: Pettijohn, 1
ii. See: columnar jointing
iii. Columns, 9 to 14 cm in diameter and 1 to 1.4 m in length, found in some calcareous shales or argillaceous limestones; oval to polygonal in section. Columns are perpendicular to bedding. Possibly a desiccation structure.
Ref: Pettijohn, 1