On an April 2010 climb, MCA’s Brent Voorhees is near the 4,236-foot summit of POW/MIA peak in the Chugach Mountains.
Peaks from left: Pioneer Peak north summit (6398); Pioneer Peak south summit (6349); East Twin Peak (5873); and Goat Rock, 5282. West Twin Peak (5472) is hidden behind Goat Rock. These mountains are all part of a geologic complex that lies within a west to east running fault called the Border Range Fault.
Major uplift of the Chugach mountains started in the Tertiary Period about 60 million years ago.
From about 2.6 million years ago (m.y.a.) to the present, a change in climate resulted in the onset of a major glaciation. Throughout the Pleistocene, from about 2.6 m.y.a. to about 11,700 years ago, glaciers were the dominant force shaping the mountains we see today. They formed the U-shaped valleys, moraines, erratics and tarn lakes found throughout Chugach State Park. Southcentral Alaska is still under great pressures from tectonic plate motions causing continued uplift of the Chugach Mountains, volcanoes of the Aleutian Range, and frequent earthquakes.
Source: State of Alaska Department of Natural Resources