State by State
Colorado
- Specimen Number
5
- Description
Cut and polished block of dimension stone composed of coarse-grained pink granite. State survey staff identifies this as Pikes Peak granite, a syenogogranite composed of pink microcline, quartz, hornblende, and biotite.
- Classifications
Igneous. Plutonic. Granitic. Syenogranite.
- Location & Occurrence
Potassic pluton from anorogenic Pikes Peak batholith, almost certainly the Pikes Peak Formation. The coarse grain texture and uniformity indicate slow stable cooling at significant depth.
- Geologic Age
Proterozoic, ~ 1 billion years old (Ga).
- Geoheritage
Highest peak in the Mountain State. Massive granite batholiths float high in the crust, especially after Cenozoic de-lamination of lithosphere. Being deeply rooted and low-density, they float high. Closeup shows classic granitic texture.
- Links
Link to State Geological Map from USGS. Link to State Geological Survey.
- Other
Credit State Survey.
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![Specimen stone for Alaska.](https://earthsciences.media.uconn.edu/wp-content/uploads/sites/3541/2022/10/05a_Colorado_210927a152.jpg)
![Closeup of Colorado](https://earthsciences.media.uconn.edu/wp-content/uploads/sites/3541/2022/10/05b_Colorado_210927a154.jpg)
![Outline map of Colorado](https://earthsciences.media.uconn.edu/wp-content/uploads/sites/3541/2022/10/Colorado-OutlineUS.jpeg)
![Geo Map of Colorado](https://earthsciences.media.uconn.edu/wp-content/uploads/sites/3541/2022/10/Colorado-USGS-OFR-2005-1351.jpg)