axial-plane foliation

axial-plane foliation

[′ak·sē·əl ¦plān ‚fō·lē′ā·shən]
(geology)
Foliation developed in rocks parallel to the axial plane of a fold and perpendicular to the chief deformational pressure.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.