Needle Mountains

The Needle Mountains are a subrange of the San Juan Mountains of the Rocky Mountains located in the southwestern part of the U.S. State of Colorado. Much of the range is protected in the Weminuche Wilderness of the San Juan National Forest. The range is notable for having some of the most rugged mountains in the state, and includes many technical climbs and scrambles. A small but dramatic east-west subrange in the northern section is known as the Grenadier Range.
Geology.
Unlike the rest of the San Juan Mountains, which are volcanic in origin, the Needle Mountains (along with the Grenadier Range) are a mass of uplifted Precambrian rocks. They consist chiefly of quartzite, granite, and amphibolite. The mountains are referred to as the Needle Mountains Uplift.