Geology - Hot Springs National Park (U.S. National Park Service) Outcropping of Arkansas Novaculite. - W. Harmon. Quartz vein cut across sandstone. - W. Harmon. Hot Springs National Park is found within the Zig-Zag Mountains, a section of the Ouachita Mountains of central Arkansas and eastern Oklahoma. The name 'Zig Zag' comes from the sharply angular folds of the rock when seen from above. The Ouachita mountains were formed during the collision of two tectonic plates around 300 Ma (million years ago). The Appalachian Mountains were formed at about the same time, and were a result of very similar forces. Geologists call the formation of these two mountain systems the Tectonic Orogeny, or mountain-building event.