The formation of Sierra la Primavera commenced about 120,000 years ago with the eruption of rhyolitic flows and domes.

[1] The tephra forms a volcanic deposit known as the Tala Tuff and consists of voluminous pumice flows.

[2][1] Subsequent filling of the caldera with water resulted in the formation of a lake through which several lava domes were created.

[1] After uplift and sedimentation filled the lake, a final series of lava domes were erupted along the southern margin of the caldera about 60,000 to 30,000 years ago.

Although volcanic eruptions are not known to have occurred from Sierra la Primavera in recorded history, it is still potentially active, containing a series of fumaroles and hot springs.