OverviewGemini Peak is located right next to Mount Sherman in the Mosquito Range in Colorado. It is sometimes regarded as one of the Centennial peaks however it does not have enough prominence to be considered a ranked peak, or a seperate mountain but rather a sub-peak of Mount Sherman. Gemini sits about 0.7 miles north of the 14er Mount Sherman which has an elevation of 14,036 ft. The drop between them however is only 171 feet. The hike from Sherman to Gemini is the most common way to gain the summit is a nice walk and affords great views. The trip to the summit from the saddle is quick and very easy. Oddly enough Gemini Peak despite being un-ranked is tied with Fletcher Mountain as the highest 13er in all the Greater Park Range. Therefore is does have some worthiness to it and actually is a nice hike. Use the National Geographic Trails Illustrated map #110 - Leadville, Fairplay for this area.
Getting ThereFourmile Creek:
Drive one mile south from from the intersection of US 285 and Colorado 9 in Fairplay. Turn west on Park County 18 and drive 10.5 miles to the old Leavick townsite at 11,240 feet. Most hikers choose to park here. Those wishing to shorten the hike can drive further up the road. Most passenger cars can go 1.5 miles further and some 4x4 vehicles can go almost 3.0 miles to the Hilltop mine at 12,900 feet.
This is the best trailhead if you plan to climb Gemini, Dyer and Sherman. Drive to the E. Third Street junction with US 24 in downtown Leadville. Go east on Third street for 0.3 miles to South Toledo Street. Turn right (south) and continue on Lake County 2. Stay north (left) after 4 miles on a dirt road that passes north of the ASARCO Mine. Continue east on Iowa Gulch's north side to the parking area at the end of the maintained road after 6.4 miles at 11,900 feet. Take the well maintained trail to the south and follow it as it reaches the south ridge of Sherman and then turns north to the summit of Mount Sherman. From here you can see the twin peaks of Gemini Peak. Continue north on the class 2 ridge for 0.7 miles to the saddle between the two peaks. The east peak is higher and a short 50 foot scramble takes you to the summit of Gemini Peak. Do not try to climb Gemini Peak directly from the Iowa Gulch parking area as the slope heading up has numerous cliff bands and much loose rock. I actually saw someone with 5 dogs almost die trying to descend this slope. If you don't wish to head up Sherman another alternative is to head east, then north from the trailhead on an old mining road to a large cabin that's lined with old newspapers on the inside. You can then continue north to the Dyer-Gemini saddle up a moderate talus slope and finish up the northwest ridge.
Camping/Red TapeClick Here for information on established campgrounds in the South Park Ranger District. The Fourmile and Horseshoe campgrounds are convenient to the Fourmile Creek trailhead.
Click Here for information on established campgrounds in the Leadville Ranger District. The campgrounds at Turquoise Lake, four miles west of Leadville, appear to be the most convenient to the Iowa Gulch trailhead. You could also camp at any of the trailheads for free.
No permit is required to climb Gemini Peak. Be aware that approaches from all sides of Gemini cross private property. Please respect the rights of the land owners and help guarantee access for others to follow.
MapBLACK: Iowa Gulch 2WD Road
GREY: Iowa Gulch 4WD Road to the old mining shed - Class 1
DARK BLUE: Gemini Peak NW Ridge Route - Class 2
RED: Dyer Mountain East Ridge Route - Class 2
LIGHT BLUE: Mount Sherman from Iowa Gulch Trail - Class 1
PINK: Sherman to Gemini Traverse - Class 2
GeologySo what exactly am I looking at in this area?
The rocks seen in the Mosquito Range, especially from Mount Sherman and southward, are part of the Precambrian basement core that was uplifted during the Laramide Orogeny 65 million years ago. The rock types are mainly gneiss and granite with pegmatite intrusions. Believe it or not, the Sawatch Range and the Mosquito Range were all one big uplift of rock that resembled a massive dome structure. The two mountain ranged are actually the flanks of an enormous anticline. Remnant sedimentary rocks found on the eastern flanks of the Mosquito Range such as the Cambrian aged Sawatch Quartz arenite, the Ordovician aged Manitou Limestone. These two formations mark the first marine depositional environment in the rock record. This means that during the Ordovician period (480 million years ago) the land that Colorado is currently on was under water. Subsequent depositional periods later deposited the Dyer Dolomite and Leadville Limestone. These sedimentary rocks dip slightly to the east, dropping into and below the large, sediment filled South Park valley where Fairplay sits today.
So what happened to the massive dome between the two mountain ranges? Why is there a giant valley there today?
The answer to this has to do with more recent geologic activity. Keep in mind that the oldest rocks in the area surrounding Horseshoe Mountain are the are the Precambrian basement rocks which are overlain by the sedimentary rocks which are easily seen in the cliffs of Horseshoe Cirque. The Laramide Orogeny caused widespread uplift throughout much of the western half of the country, which is what created the Sawatch and Mosquito Mountains. About 30 million years later, around 30-35 million years ago another key event shaped this area. This was the Rio Grande Rift which is the same event responsible for forming the San Luis Valley. The massive dome that should connect the Sawatch and Mosquito Ranges was pulled apart during a rift event similar to the East African Rift happening today. For some reason that isn't yet fully known the western half of North America underwent massive tension despite millions of years of compression prior, which resulted in the crust of the earth to pull apart. This is very evident in Nevada with the hundreds of small mountain ranges with deep valleys between them all. Normal faulting resulted due to the tension and a large valley opened up between the Sawatch flank and the Mosquito flank of the anticline. Over time, the valley began to fill with sediment which washed down from the mountains to the east and west filling in the valley...similar to the was the San Luis Valley has been filled in. Thousands of feet of sediment fill these rift valleys. Today the valley between the two ranges makes a great path for a major river...The Arkansas River. The rifting ceased and the crust became pretty stable in all of the inter-mountain west 20 million years ago but only after a massive volcanism event in the San Juans which deposited some of the youngest rocks in the state however this event had a smaller effect on this area of Colorado.
So why did this area have such a rich mining history?
This is largely for two primary reasons. The main reason that this mountain chain is so rife with mined precious metals is because it sits on the east flank of the Rio Grande Rift and over top of the Colorado Mineral Belt. Interestingly, the Gore Range to the north which formed from nearly identical geologic processes is not as mineralogically rich because it doesn't sit atop the Colorado Mineral Belt, and thus has not received the mining that the Tenmile and Mosquito Ranges did. The Mosquito Fault is a major north-south normal fault that formed during the onset of the Rio Grande Rift and parallels the western flank of the Mosquito Range. Miners usually always dig where faults are located, especially major ones, because they provide great paths for water to flow through the rocks. When water flows through the rock, it alters it and changes the mineral makeup of the rock. It just so happens that some of the more valuable or desired minerals are the byproduct of altered rocks especially if they are concentrated which flowing water has a tendency to do. Certain minerals or elements become dissolved in the water and if a slight change in temperature, pH, or pressure occurs (which always will if the water is flowing), these minerals will drop out of the water all at once and become concentrated and usually be deposited within the faults. Hence why miners dig where faults are located and this area has a whole lot of faults. Also, since much of the basement rocks in the area have trace amounts of gold, silver and other valuable elements already in the rock, when they become concentrated from the process described above, it wasn't that uncommon for lucky strikes to be found. The second primary reason for the rich mining history is likely the accessibility. The Mosquito Range is a long, narrow mountain range that is very gentle. Roads were easy to make and travel on foot was unobstructed. This allowed miners to search every inch of land they desired. This rich mining history has made for very accessible mountaineering and hiking today and also provides a great place for 4-wheel and snowmobile enthusiasts.
External LinksWeather Forecast
City of Leadville
Lists of John
Sherman, Gemini, and Dyer Trip Report
Iowa Gulch Trailhead Current Info
Good Trip Report for the 3 Peak Loop
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