10/09/2007
The geology of Rocky Mtn. National Park
What is geology?
Geology is the study of the Earth, the materials of which it is made, the structure of those materials, and the processes acting upon them. Part of geology is classifying and determining what was happening on our planet over time through rocks. Rocks are divided into three major classifications; • Igneous- rocks created by volcanism and the cooling/ crystallization of magma.
• Sedimentary- rocks created by the compaction and cementation of sediment created by the weathering of pre-existing rocks of igneous, metamorphic or sedimentary origin.
• Metamorphic- rocks that are formed by metamorphosing pre-existing rocks through heat and pressure. Metamorphic rocks can be made from any of the three types of rock.
Rocky mountain national park is a great place geologically, because there are all three of these types of rock present in the park.
Geology of Rocky Mtn. National Park: The predominant type of rock in Rocky Mountain National Park is granite, which is an igneous rock. There are two types of granite present in the park; Pikes Peak granite and silver plume granite. Pikes Peak granite is easily identified by its salmon pink color, created by an abundance of orthoclase feldspar. There are also whitish clear quartz crystals and pieces of dark, flaky, shiny mica. Silver plume granite which is more of a mottled black and white coloration due to the presence of a different type of feldspar and the continued presences of quartz and mica. The most common sedimentary rocks in the park are from the Dakota sandstone formation. It is exposed in many places throughout the Rocky Mountain region and extends from New Mexico northward for 1,000 miles or more. It is prominent because the sand is cemented together firmly to form a quartzite which resists erosion very well. There are also rocks from the Morrison formation, which is composed of mudstone, sandstone