Crystal, Gunnison County, Colorado
Parent Rock
### Parent Rock

The rock in the Elk Mountain Range in the area surrounding Crystal is composed primarily of (90%) [sedimentary](/wiki/Sedimentary_rock "Sedimentary rock") material, including mostly coarse clastics, [shale](/wiki/Shale "Shale"), and [limestone](/wiki/Limestone "Limestone"). The last 10% is mostly [igneous](/wiki/Igneous_rock "Igneous rock") rock. The [Maroon Mountains](/wiki/Maroon_Bells%E2%80%93Snowmass_Wilderness "Maroon Bells–Snowmass Wilderness") formations (which are the closest notable mountains to the valley town of Crystal) are composed of mostly [sandstone](/wiki/Sandstone "Sandstone") and [siltstone](/wiki/Siltstone "Siltstone"), which are coarse clastic rocks and are exposed for the most part. Fine clastic rocks cover a fifth of Crystal. Glacial remain and out\-wash created the sandy loam material which fill the valleys in the area, including the bottom of the Crystal River which runs through the valley in Crystal and surrounding towns.


How were the valleys in the area created, including the bottom of the Crystal River?