"Heavy impasto" refers to a technique in painting where the paint is applied very thickly to create a textured and three-dimensional effect on the canvas. Full definition
An unusually heavy impasto of lines, drips and dots are applied atop the canvas and on another until vivid repetitions of color lay way to waves, cascades and small explosions of pure paint. (kohngallery.com)
From 1960 he adopted a more geometric style, painting complex cube - like structures with heavy impasto paint. (biography.com)
Inside these baroque forms are uniformly sized blocks, each square its own pure color, sometimes only subtly distinguished from neighboring colors... Gordon's shapes are carefully molded in heavy impasto paint with a palette knife, a bas - relief in color that pops off the canvas... [Diamond] uses nature - based drawings to create forms that at first glance resemble figures but after closer study escape into the realm of the imagination. (painters-table.com)