Wheeler Geologic Area

True to its name, Mineral County is a significant study area for ancient geologic activity. The formation of the La Garita and San Juan mountains began about 30 million years ago. Eruptions from massive volcanoes, like the Creede Caldera, were followed by tremendous flows of ash and mud. As the layers of volcanic debris cooled, crystals and mineral ores collected into veins and pockets to create extensive mineral fields. This era of mountain building laid down the volcanic tuff that has become the Wheeler Geologic Area. Water erosion then carved a starkly impressive landscape of fragile capstones, needles, and spires.

Named for the 19th century surveyor of the West, Captain George M. Wheeler, this unique area became a National Monument in 1908. Wheeler’s status later changed to “Geologic Area.” The Creede office of the U.S. Forest Service (719-658-2556) administers this remote landmark. Each August Volksmarch schedules an overnight hike into this unique natural wonder.

Roadside Geology of Colorado’s Highway 149

Creede to Spring Creek Pass

As you are driving along Highway 149, imagine that this landscape was an erupting volcano millions of years ago, spewing out rocks the size of houses. This area is part of a giant crater known as the Creede Caldera.

Stop 1. Airport Corner. At this location numerous plant fossils, mineral impressions and occasional insect fossils may be found on the hill to the north side of the road by parting the thin layered rock. After the formation of the Creede Caldera, a salty lake formed in the crater, which received palnt debris and sediment as they eroded down from the surround hills. This sediment eventually turned into rock that is mostly composed of very fine grained volcanic ash.

Stop 2. Point of Rocks. This area, just off Hwy 149 on Middle creek Road, is interesting because you can see several types of rocks from two different calderas. The Bachelor Mountain Member of the Carpenter Ridge Tuff was a flow of volcanic ash that erupted from the Bachelor Caldera, which is located somewhat north of, and predates by several hundred thousand years, the Creede Caldera. Near this formation is an outcrop of breccia (pronounced “bret’-shia”), composed of broken, angular rock fragments. Also at this stop is an outcrop of Snowshoe Mountain Tuff (another volcanic ash deposit) that erupted from the Crede Caldera about 27 million years ago.

Stop 3. Entrance to Rio Grand Campground. Here you’ll see an example of a lava flow overlying a debris flow, both associated with the first and by far the largest of the calderas to from in the area, the 1000-square mil La Garita Caldera.

Stop 4. North Clear Creek Falls. Here, North Clear Creek suddenly tumbles over tuff that erupted from he San Luis Caldera Complex – a family of three calderas that formed over a short period of time north of and probably slightly before the formation of the Creede Caldera.
RockHounding in Mineral County

1) Pool Table Road
At the 4 ½ mile marker on Pool Table Road, pull over and hunt both sides for small agate and jasper

2) City Dump Road
1 ½ miles southeast of Creede, turn left on the “City Dump” road and then turn right at the fork. Park at the Wason Barn. Walk about 200 yards to a ravine and there you will find flouresant calcite (green and sometimes cherry red) and it may also be translucent.

3) Airport Corner
50 yards before the sharp right hand turn there is a small ravine. In that ravine one can look for fossils.

4) Four Wheel Drive
Whited Creek at Phoenix Park. At the point in Phoenix Park where the jeep trail crosses the water, pull over and park. Follow the creek up stream ½ mile and there one can begin looking for geodes. Geodes will contain common opal.

For more information or maps on Geology and RockHounding in the Creede and Mineral County area, please contact the Creede and Mineral County Chamber of Commerce.