The area near the Indian Heaven vicinity is composed of Western Cascade rocks from the Eocene to Miocene including andesite, tuffs, mud flows, pyroclastic flow deposits, and other volcaniclastic materials, as well as High Cascade rocks that date from between the Pliocene and Holocene epochs. Strata of rock underlying the area has been deformed to create faults, fractures (separations in geologic formation), volcanic igneous intrusions, and a gradual, dipping syncline that trends north to south. The Indian Heaven field resides within the syncline's trough, and it consists of High Cascade rocks, which are far less altered than the surrounding rock strata. Similar to other Cascade volcanoes, the Indian Heaven volcanoes were fed by magma chambers produced by the subduction of the Juan de Fuca tectonic plate under the western edge of the North American tectonic plate.