On surface the massif is made up of Middle to Late Jurassic-aged felsic volcanic rocks.

As such the Deseado Massif is one of the oldest regions of Patagonia as it existed in some form during the Paleo and Mesoproterozoic.

In the Neoproterozoic the Deseado Massif together with the Falkland Islands formed part of the supercontinent Rodinia.

[2] The eastern sector of the Deseado Massif contains a Jurassic caldera with a zircon U–Pb eruption age of 178.7 ± 1.9 million years.

[1] In 2017, an international group of scientists, while researching the origins of gold, historically established that it "came to the Earth's surface from the deepest regions of our planet," evidenced by their findings in the Deseado Massif.