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Geology
Geology
Roxborough State Park

​​​​​Roxborough State Park is a designated Colorado Natural Area, National Cultural District and National Natural Landmark and is located along the foothills of the Rocky Mountains in the ecotone between plains grassland and Front Range forest communities. The park encompasses 3,329 acres with elevation ranging from 5,900 to 7,280 feet above sea level. Willow Creek, Little Willow Creek and Mill Gulch are the primary drainages in the park. Dramatic Hogbacks, Spires and Monoliths encompass the landscape.

The most striking feature for visitors to Roxborough is the dramatic Fountain Formation.  This spectacular tilted sandstone began over 300 million years ago with the gradual erosion of the Ancestral Rocky Mountains.  Today these red sandstones stand beautifully at ​​​​​Roxborough at a sixty degree angle and are the result of millions of years of uplift and erosion.

There are excellent examples of exposed geology from the Precambrian to Late Mesozoic, including hogbacks of Cretaceous, Permian, and Pennsylvanian age. Erosion of steeply dipping monoclinal sedimentary sections has resulted in the series of three major hogbacks and strike valleys, exposing highly scenic dipping plates, spires and monoliths. Precambrian gneiss and biotite-muscovite granite are exposed on Carpenter Peak. 

Carpenter Peak

The westernmost hogback is Paleozoic Age Fountain Formation sandstone, originating from an accumulation of sediments that eroded from the Ancestral Rocky Mountains. It is conspicuously red due to oxidation of iron minerals. The central hogback is Permian Age Lyons Formation, which formed from windblown sand and stream deposits following erosion of the Ancestral Rocky Mountains. The easternmost hogback, Cretaceous Age Dakota Sandstone, is composed of Lytle Formation floodplain deposits and Platte Formation beach and shallow ocean deposits.