Mount Morning has been active during the Miocene, Pliocene and Pleistocene. Argon-argon dating and potassium-argon dating have been used to infer the duration of volcanic activity at Mount Morning. Gandalf Ridge has yielded ages of 18.7±0.3-15.5±0.5 million years, Pinnacle Valley 15.2±0.2-13.0±0.3 million years, Mason Spur 12.8±0.4-11.4±0.2 million years, rocks below the summit of 6.13±0.20-~1.00 million years and 4.51±0.31-0.02 million years on other formations. Some of these eruptions may have deposited volcanic ash over the McMurdo Sound area. Even older activity at Mount Morning may be recorded in volcanic deposits from Cape Roberts which go back to 24.1 million years ago. This is a long lifespan for a volcano by Antarctic standards, and may be due to tectonic factors that kept magma generation focused on Mount Morning for a long time. Loading by glaciers may have influenced volcanic activity at Mount Morning.