pinch-and-swell structure

pinch-and-swell structure

[¦pinch ən ′swel ‚strək·chər]
(geology)
A structural condition common in pegmatites and veins of quartz in metamorphosed rocks; the vein is pinched at frequent intervals, leaving expanded parts between.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.