- A plane through
a rock fold that
includes the axis and divides the fold as
symmetrically as possible.
Source: Leet, L. Don. 1982.
Physical Geology, 6th Edition. Englewood Cliffs, NJ: Prentice-Hall
- a. A more or less planar surface that intersects a fold in such a manner
that the limbs of the fold are symmetrically arranged with reference to
b. The plane of the optic axes of an optically biaxial crystal.
c. A crystallographic plane that includes two crystallographic axes.
d. Of geologic structures, a plane that intersects the crest of the trough
or a fold such that the limbs, or sides, of the fold are more or less
symmetrically arrayed with reference to it.
Dictionary of Mining, Mineral, and Related Terms