Blackrock Desert overnight

By webmaster at 10:47 pm on May 29, 2008 | No comments

The Leadville Mine northeast of Gerlach in Washoe County, Nevada, has produced a variety of metals from ores associated with porphyritic dikes in andesite. There is a mention in the literature that there were large fluorite crystals associated with the deposits, although there are no real details describing the occurance. It was worth a trip to see this area and some new country and to check out some geode areas on the north side of the Blackrock.

Lupines & Balsam RootWe left Reno early and had breakfast at Bruno’s in Gerlach, the iconic restaurant on the Black Rock-Smoke Creek junction. We traveled by paved and then gravel roads about 35 miles NE to the turn into the Leadville District. A good jeep trail leads to the mine site. It was a very windy and cold day with showers at the 6,000 plus foot elevation, but the flowers were out and a lone antelope and several groups of mustangs didn’t seem to mind the weather. We spent several hours climbing over mine dumps and looking at prospect pits on the main structure and to the southeast on several parallel dikes. The dumps produced several specimens of massive galena, one of sphalerite and numerous samples of sulfide-rich waste rock. There was no recognizable fluorite on the dumps or on the mineralized structure on a single exposure on the drainage south of the main workings.

Leadville mining districtWe left Leadville and drove north to check an area where Sam Knipmeyer, my digging partner, had prospected with his dad in the 80’s. There is a nice display of petrified logs next to the road, protected from passing rock hammers by a sturdy fence. We returned to the north edge of the Black Rock Desert and turned NE again on Soldier Meadow road. We decided not to drive on the playa as it had showered much of the day and might have turned the track to mud. We passed an opal mine (formerly, Little Joe) and proceeded to the Mud Meadows Reservoir and turned south along the west flank of the Black Rock Range. This track follows the approximate route of the 49er’s as they treked to the Highrock Canyon and the Northwest. We passed the site of Hardin City, history unknown. Ruins consist of two eroded piles of cut ash fall tuff blocks that were buildings near a boggy spring.

Hardin City

Double Hot Sprigns
Top, Hardin City Ruins – Bottom, Double Hot Springs

Some 5 miles to the south is Double Hot Springs, a series of pools with temperatures in the dangerous range. It was to late for a bath, so we turned back north a mile or so to a flat dry camping spot. It was windy and rainy all night but the area was surprisingly dry in the morning.

CampsiteAfter breakfast and packing up camp, we re-traced our route to the north and found a track into the hills to the east. The area is reported to have a variety of chalcedony geodes weathering from basalt. We did find a number of specimens, nothing spectacular, and a lot of chips from sites along the flanks of the valley. Some were of a very pretty red jasper and had clearly been shaped as scrapers. The highlight, actually, was at the end of a small box canyon in one of the basalt layers where we found a nesting pair of prairie falcons. They were very upset with our visit but calmed down quickly as we left.

Prairie Falcon Nest

Seeing rain to the south and fearing a muddy track on the playa, we again headed south to Double Hot Springs. We took pictures and reflected on the marker with a quote from a log dated August, 1849, in which the writer remarked on the springs and the fact that they had rested and “boiled beans” (in the springs) as they passed, on the way up the trail. We then headed SW to the track across the Black Rock where for 35-40 miles one can drive in nearly a straight line at 50-60 miles per hour. The dust plume was spectacular!

Track across Black Rock

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Tomahawk Basin, Colorado: Fluorite

By webmaster at 11:02 am on April 24, 2008 | No comments

In the mid-1970’s I spent some time working in SW Colorado in the La Plata Mountains near Durango. This area has produced significant gold (the Bessie G mine, for example, was active at that time) and has been investigated for its porphyry copper potential and uranium as well.

The Tomahawk Mine and basin are located above timberline in the western part of the complex. Rocks in the area include a variety of intrusives and metamorphosed sediments that form the high ridges and cliffs around the head of Tomahawk Creek. The Tomahawk mine produced gold in the last century. At the time I worked in the area there was still a very thin, rich vein containing visible gold accessible (if you were a skilled rock climber) on the cliff face at the creek near the mine ruins.

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Above: Tomahawk Basin seen from high ridge to SE.

Below: Tomahawk Mine structures in 1975.

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What passed for a road ended a few hundred yards west of the mine at a drill site located near a small intrusive complex. Talus from the high cliffs to the south of this intrusive contained scattered vugs that were mineralized with epidote, quartz, K-feldspar and rare fluorite. The fluorite crystals were simple octahedrons of a rich violet color. Their maximum size was about 2 mm.

I have always thought that it would be worthwhile to investigate the area for the source of the fluorite. Perhaps there are larger cavities and better crystals in the larger talus or lower cliff faces a few hundred feet up and to the south of the intrusive. Are there any of you energetic young collectors interested?

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