Not marbled paper; rather, this is a section of a rock, the patterns formed when the rock was melted and fluid. Marbled patterns, micro and macro, are found throughout nature, all formed in accordance with the same laws of physics.
A place for show-and-tell, wondering aloud, and wandering the trails of curiosity . . . Comments, corrrections, additional information, fresh insights, other interpretations, more images, or related observations will be welcomed!