Mountains in Motion / Hot Rocks

Though visible glaciers gleam remotely between distant peaks, the valley below is strewn with signs of massive glaciation, including stranded boulders, gouged-out ponds, and gravel outwash plains. The last major glacial advance moved through this valley about 10,000 years ago, and to a geologist’s eye the landscape remains active with glaciers. Denali’s wandering meltwater rivers, cloudy with glacial silt and rock fragments, show ongoing glaciation and mountain carving. The many-colored polychrome rocks are hardened lava from a period of mountain building 100 million years ago. Although that timeframe seems unimaginably distant, this area continues to experience seismic activity, with frequent earthquake tremors, and as crustal plates along the Denali fault keep grinding together, mountains of the Alaskan range may still be rising.

Cantwell, Alaska · United States