Geography of Colorado
The Rocky Mountains within Colorado contain 54 peaks that are 14,000 feet (4270 m) or higher, known as fourteeners. The mountains are timbered with conifers and aspen to the tree line, at an elevation of about 12,000 feet (3,650 m) in southern Colorado to about 10,500 feet (3,200 m) in northern Colorado; above this only alpine vegetation grows. The Rockies are snow-covered only in the winter; most snow melts by mid-August with the exception of a few small glaciers. The Colorado Mineral Belt, stretching from the San Juan Mountains in the southwest to Boulder and Central City on the front range, contains most of the historic gold and silver mining districts of Colorado.
Sawatch Uplift
The Sawatch Uplift is a prominent geologic anticline in the Rocky Mountains in central Colorado in the United States. It was formed as a bulge in the North American Plate approximately 70–65 MYA during the Laramide orogeny that created the modern Rocky Mountains. The uplift runs north-south for several hundred miles from central Colorado into northern New Mexico. The Sawatch Range and Mosquito Range were both formed as part of the uplift. Approximately 35 MYA, stresses in the continental plate in the center of the uplift caused the center to collapse, forming a trough between the Sawatch and Mosquito Range that is part of the larger Rio Grande Rift. The trough runs southward from Leadville, CO into New Mexico. The northern part of the rift forms the headwater valley of the Arkansas River.