| This view from the Circle Creek Overlook shows the unique weathering characteristics of the granite. Much of bedrock in the park area is crystalline rock formed about 2.5 billion years ago. These rocks are a part of the Green Creek Complex, an extensive belt of ancient igneous and metamorphic rocks in the region; these rocks are some of the oldest rocks exposed in the United States. However, much of the landscape within the park consists of younger, lighter-colored granitic plutons that locally intruded the ancient rocks about 30 million years ago. Since then, the land has slowly risen and erosion has stripped away rocks at the surface, eventually exposing the granite (Miller and Bedford, 1999; Miller and others, 2008; Strickland and others, 2007). |
