Other outcrops occur farther southwest at Navarrette Peak, southeast at Wallace Rock[8] and northeast at Erven Nunataks.

[3] Argon-argon dating has yielded ages of 36 and 29-27 million years for the volcanic rocks, making them the oldest in Marie Byrd Land.

[19] The volcano probably formed at the surface, perhaps in contact with an early Oligocene ice sheet[1] or more likely mountain glaciers,[20] as the rocks display evidence that the volcanic eruptions took place in shallow water, most likely meltwater.

[1] During the late Cretaceous and Eocene-late Cenozoic, continental rifting occurred in the Ross Sea and West Antarctic Ice Sheet area.

Beginning with the Oligocene, an ice sheet began to develop in Antarctica and acquired present-day dimensions during the Miocene or Pliocene.

[23] During the 20th century, Mount Petras was viewed as a volcano that had formed deep under ice on a Cenozoic marine erosion surface covering West Antarctica, which had then been deformed by tectonic uplift.