The carbonate rocks that form Heart Mountain were deposited on a basement of ancient (more than 2.5 billion years old) granite when the area was covered by a large shallow tropical sea.

Between 75 and 50 million years ago, a period of mountain-building called the Laramide Orogeny caused uplift of the Beartooth Range and subsidence of the Bighorn and Absaroka Basins.

Immediately following this period of mountain-building, volcanic eruptions began to form the now extinct volcanoes of the Absaroka Range that lie to the south of the Beartooths and extend into Yellowstone National Park.

Another model involves injection of numerous igneous dikes with the resulting heating of water within pores in rocks causing an increase in pressure which initiated sliding.

Some geologists have suggested that hot pressurized water (hydrothermal fluids), derived from a volcano which sat north of Cooke City, Montana, effectively lubricated the sliding surface.