Ode to South Pass

Twas the spring of ’78,

When prospectors tipped beer with squirrelly mates, 

At the Mercantile we heard cheers and moans,

Interrupting exaggerations about gold in shear zones.

Along came a geologist named GemHunter Dan,

Twas said to be a hard rock man, 

Surrounded himself with rocks of old,

Including amphibolite, a host for gold.

The GemHunter

In the summer, when snow buried his tent, 

Off to Laramie is where he went,

He swore he would be back with hammer and map,

And would also bring a miner’s cap.

Atlantic City with population of 40,

Dogs, Barbara, Steve, Tony and Shorty,

Blessed by a geologist with all his maps,

Found gold at a mine face covered with bats.

Down the shaft in stopes so cold,

Then up in a raise he was told,

Is where the yellow metal resides so bright,

In tunnels and chutes lit by a miner’s light.

The Carissa kept its secrets deep,

Until the State took her while we weeped,

A billion in gold, now lay with mold, 

So tourists can enjoy a town of old.

There was a Mary Ellen mine and its mill,

With Steve the captain at the wheel,

We descended 240 feet of incline, 

Followed the vein while my assistant whined.

He’s claustrophobic at 240 deep,

Carrying him up a ladder that’s way too steep,

So we yelled “Jay” climb to the light,

He made the head-frame before midnight.

Then there was Barbara so bold and old,

Swindled a tourist with jars of fool’s gold, 

The pyrite was shiny, brassy and cold,

But the tourist was mad when he was told.

He plugged his whiskey bottle with a cork,

Decided to get even by calling her dork,

And that evening, while she slept on a floor,

Barbara’s Cadillac was ablaze from door to door.

Gold panned out of the Rock Creek dredge tailings

Barbara awoke to whisky and flakes,

We wondered who next she would take,

When into the Mercantile strolled a mark,

Dressed like a dandy at the bar he parked.

Where’s the Mary Ellen he asked so kind,

So Barbara offered him title to a mine,

No thanks said the gentleman from Missouri,

You see, I’m really in a big hurry. 

Besides the mine cannot be sold,

After all its my mine he told,

So Barbara drank another shot,

Another swindle and she was caught.

Then there was Shorty with wet pockets and old, 

Sat in his trailer to count his gold,

Cut a hole in a single wide on Rock Creek, 

To fill his honey pot and make everyone reek.

Atlantic City is the place,

To mine gold and investors with hast, 

Dig the gravel and fill a mucker,

A sluice, a pan, or a sucker.

Enough! I said as I headed out with cap,

Grabbed my Brunton and began to map,

Eight quadrangles, 500 square miles, a dozen or so mines completed,

Searched for the yellow stuff and found more Mormons than needed.

Published a paper a book and cried,

Why do bureaucrats have to lie,

Elected a crooked Democrat, 

With a State geologist, a two-bit rat.

So long I said to South Pass of old,

You can keep your Democrat and your gold,

Wyoming democrats smell ripe and old,

Just like Shorty’s honey pot I’ve been told.

Mining districts and mineralized terrains of Wyoming 

(after Hausel, 1997; and Hausel & Hausel, 2011). 

South Pass, what a glorious place! I saw South Pass for my first time in 1978. The vast gold mining region and greenstone belt along Highway 28 at the southern tip of the Wind River Mountains was just south of the town of Lander in western Wyoming. It was love at first site! The geology, the old mines, a couple of tiny towns partially occupied by ghosts - it was a geologist’s paradise. 

I told the greenstone belt, "I will be back to map you". And, I did get back and accumulated fond memories during the five summers in a tent while mapping the 450 to 500-square mile granite-greenstone belt and more than two dozen gold mines.

South Pass is a gold prospector's paradise. At least it use to be. The geology forms a tightly folded, granite-greenstone belt, a geological basin, with banded iron ore deposits along the western and eastern limbs of the belt. If you are unfamiliar with this kind of geology, I recommend searching the Internet for a summary on ‘greenstone belts’. Archean age ‘greenstone belts’ and ‘gold belts’ are often synonymous terms to geologists who work in Archean (older than 2.5 billion years) rocks.

Schematic map of the South Pass granite-greenstone belt 

showing location of the South Pass-Atlantic City and Lewiston 

districts, and McGraw Flats and Oregon Gulch paleoplacers (after Hausel, 1991)

Decades ago, iron ore was mined at US Steel’s Atlantic City mine; a mine that was a show-case for the company. But, the once majestic mine closed and is now a lake (42°32'26"N; 108°44'44"W) sitting along Highway 28.

The iron ore occurs in a rock known as banded iron formation (BIF), or taconite. It consists of alternating layers of magnetite and quartz. BIF is a good source for iron, and some are also sources for gold, particularly where quartz veins and sulfides such as pyrite, chalcopyrite or arsenopyrite occur in the rock. Take the Homestake mine as an example: nearly 40 million ounces of gold were mined at Homestake over a century, and it was classified as iron formation. Other examples of gold in iron formation occur at the Lupin mine in the Northwest Territories, Detour Lake in Ontario, Mt. Morgans in Western Australia, and others in Zimbabwe, India and Brazil.

Folded BIF from the Atlantic City iron ore mine, Wyoming, with
quartz veinlets, 

The BIF at South Pass lies in a meta-sedimentary unit known as the Goldman Meadows Formation that includes mica schist and quartzite resting on older rock of the Diamond Springs Formation. The average iron content of the BIF is upwards to 40%. US Steel operated the mine and recovered more than 90 million tons of iron ore prior to closing the mine in 1983. The geology of the Goldman Meadows formation indicates these rocks were originally deposited in a shallow sea on a stable platform possibly 3 billion years ago.

Copper-stained BIF from the Seminoe Mountains greenstone belt,
Wyoming, with both black and white quartz veinlets
mixed with dark gray magnetite.

When the Atlantic City mine closed, the BIF was unsampled for gold until I asked about archived gold assays. The company was so focused on iron, they didn’t consider the possibility of gold. I got permission to visit the mine, but my annual assay budget at the Wyoming Geological Survey was a pitiful $100 per year (at that time, $100 would cover 3 to 5 assays), so I was unable to test the rock for gold since I had already spent my annual assay budget. Even so, I found quartz veinlets cutting the BIF with pyrite and chalcopyrite as well as other veinlets that penetrated the rock foliation - good signs for gold. Even so, I was unable to prove the rock had any gold. But when the beer started flowing at the Atlantic City Mercantile and I brought up the subject, former iron miners swore they had seen visible gold in the open pit. In 1981, I had found highly anomalous and localized gold in BIF in the Seminoe Mountains greenstone belt east of South Pass, but we still don't know if there is any gold in the BIF at South Pass. 

The Diamond Springs Formation, the lowermost mappable rock unit at South Pass includes primitive, metamorphosed, igneous rock known as amphibolite (metamorphosed basalt) and serpentinite (metamorphosed komatiite). Samples of this material contain 18 to 38% MgO, a trace to 1.0% chromium; and trace to 0.26% nickel. Based on chemistry and rock mineralogy, I interpreted these ancient and altered rocks to originally be basalts and komatiites deposited on the earth’s surface 3 billion years ago. Komatiites are rare volcanic rocks often found in greenstone belts and are essentially restricted to Archean age (older than 2.5 billion years).

Locally, some of the serpentinites have cross-fiber asbestos veinlets that were prospected in the early 20^th century for asbestos, while other outcrops are massive, and a few have cumulate texture. Cumulates are magnesium-rich metamorphosed volcanic flows that erupted directly from the earth’s mantle and when they began to cool, tiny olivine grains crystallized in the lava, sank, and accumulated at the bottom of the flow producing a sandstone-like, cumulate texture. 

Rock foliation and bedding of dark gray to black meta-greywacke 

of the Miners Delight Formation is nearly perpendicular to Rock 

Creek with its dredge tailings in the foreground. In other words, the 

bottom of rock creek is lined with many natural riffles to trap gold. 

By the way, the name ‘Miners Delight’ would be better applied to a beer.

Magnesium-rich volcanics are good rocks to prospect for nickel, chromium, platinum-group metals and gold: none of which I detected in anonymous amounts at South Pass. Elsewhere in Wyoming, I found anomalous nickel and palladium in another magnesium-rich rock at Puzzler Hill in the Sierra Madre Mountains, and chromite was found nearly a century ago in serpentinite in the Laramie Mountains near Douglas. Nickel anomalies are also reported in the Laramie Mountains anorthosite complex, where a king’s ransom in labradorite (spectrolite) and iolite gemstones occur. 

As a rock hound or prospector, any time you see the term 'anorthosite', it usually means it's a good place to search for labradorite. And if you are interested in iolite - that is a little more complicated. Look in areas where the rocks have been metamorphosed and have high alumina. Or, simply look for the term 'cordierite' applied to metamorphic rocks. Cordierite is the geologist's designation, and few geologists know what gemstones look like. Often they mention the mineralogical term but completely overlook the fact that the mineral may be gem quality. But remember, there is a lot of cordierite out there that is very poor quality.

At one location north of Laramie based on the few samples I collected on a county road, and based on historical estimates of the amount of cordierite exposed in trenches, there could be a deposit with more than a trillion carats of iolite. Nearby, I found some extraordinary deposits of iolite at Palmer Canyon and Grizzly Creek. Iolite is a low-value gem.

Miners Delight mine was developed on a 3 to 16 foot wide shear zone that has been traced over 2500 feet on the surface. Gravels in nearby Spring Gulch draining this shear zone produced 1500 ounces of gold including several 1 & 2 ounce nuggets, a 6 ounce nugget, and a sample of auriferous quartz described as “the size of a water bucket that was filled with gold”. Samples collected across the shear zone by the the author assayed from 0.01 to 0.36 ounce per ton gold.  A historic prospectus reported there were 2,400 feet of drifts accessed from a 250 foot deep shaft and the mine produced 60,000 ounces. The gold tenor ranged from 0.3 to 110 ounces per ton of gold. It is likely that this property still has considerable ore at depth.

Some gemstones are also found in serpentinites - for instance, my good friend Robert Odell (RIP) found hundreds of tiny, blue sapphires in alumina-rich serpentinite near the Red Dwarf ruby deposit in the Granite Mountains of central Wyoming northwest of Jeffrey City. While exploring northern California for diamonds, I came across chromian diopside in serpentinite. Chromian diopside is considered to be a kimberlitic (diamond) indicator mineral and some specimens yield spectacular emerald-green gems. In central California, east of Sacramento, I also found gem-quality benitoite in the river adjacent to a serpentinized breccia pipe I examined for diamonds. The benitoite was flawless and likely eroded from nearby aluminum-rich serpentinite. I was hoping to get back to that area some day and search for the source for those gemstones, but never did. Even though some serpentinites contain gemstones, the South Pass serpentinites lack anything of value, other than for a few crooked jade dealers who sell it as jade.

The base of the South Pass greenstone belt is interleaved with gneiss. Similar gneiss found elsewhere in the Wind River Mountains is dated from 2.8 to as much as 3.8 billion years old. Age dates in the South Pass granite-greenstone belt include the Louis Lake granitic batholith (which intrudes the greenstone belt) and is dated at 2.6 billion years old. Some poor quality helidor (yellow-green beryl) and rare aquamarine beryl occurs in granite pegmatite associated with this batholith. A 2.8 billion year age (isochron) was determined for the Miners Delight Formation metamorphic event that recrystallized all of the rocks of the greenstone belt. A similar age was determined for a vein at the Snowbird mine located in the Miners Delight Formation, suggesting that a temporal connection exists between metamorphism (rock recrystallization) and gold mineralization. It is likely much of the primary gold at South Pass leached out of the rock during metamorphism and migrated to zones of lower pressure (i.e., fractures), such as shear zones that lie parallel to near-parallel to regional rock foliation. Thus, when prospecting at South Pass, it is important to learn as much as possible about these shear zones.

False bedrock on Rock Creek (42°29'10"N; 108°42'22"W). Layers of false 

bedrock can lead placer miners to give up after they recover gold from a 

pay-streak thinking they are on bedrock. The handle of the shovel rests 

against the massive clay layer (claystone) that acts as a barrier to gold. 

Siting above this layer, cobbles and pebbles in the overlying conglomerate 

are characteristic of stream gravel and this material carries gold which 

is enriched at the interface between the conglomerate and the claystone. 

Below the claystone, more gold-bearing steam gravel is visible. As one 

digs further down into the placer on Rock Creek, similar false bed rock 

layers will likely be found. On Smith Gulch (42°31'3"N; 108°42'19"W), 

two placer miners (Hank Hudspeth and Buddy Presgrove) found a similar 

false bedrock layer with considerable gold sitting on false bedrock and  

found additional gold below the layer on actual bedrock. 

Sitting on the Goldman Meadows Formation is the Roundtop Mountain Greenstone Formation - a belt of metamorphosed pillow basalts deposited in an ancient sea. Some pillow basalts are so well preserved that I was able to use them the tell which way was up in this part of the stratigraphic section. This is helpful when mapping rocks in greenstone belts, because most greenstone belts were compressed and squeezed like an accordion during tectonic stress, and many rock units can be overturned. 

If you are not familiar with pillow basalt but familiar with the Black Cat snake fireworks made from sodium bicarbonate and sugar, you have a good idea of what pillow basalts look like. Pillow basalts erupt under water expanding like snakes. Where they rest on a rock layer, they tend to sag until they completely solidify and look like a pillow. Since they sag, one can determine which way was up at the time of deposition. The pillow basalts at South Pass are now tilted nearly 90^o.

The Roundtop Mountain Greenstone is overlain by the Miners Delight Formation, which is estimated to be 5,000 to 20,000 feet thick and seen throughout much of the exposed greenstone belt. Determination of the thickness of this unit is complicated by folding and faulting, and in most places it has been tilted nearly 90^o and many places it is overturned. This formation consists primarily of dark gray to brownish black meta-greywacke. Greywacke (or meta-greywacke) is nothing more than dirty sandstone deposited along the edge of an ancient continent.

Non-mineralized rocks of the Miners Delight Formation contain a trace to 0.051 ppm Au (gold) (compared to a worldwide average of 0.002 ppm. Essentially all of the rock units at South Pass exhibit above average gold content and these were deposited in a shallow to moderately deep oceanic basin by volcanic activity and erosion of an adjacent continental shelf. All of the old Archean rocks were intruded by a belt of gabbroic rocks along a rift. These intrusive rocks are now classified as amphibolite but were originally gabbro, diabase, andesite and komatiite. 

As the entire belt was compressed and folded along the edge of the subduction zone 2.8 billion years ago, shear zones formed along the contact between the Miners Delight meta-greywacke and the amphibolites due to the competency contrast between the two rock types. This is a very important concept for gold prospectors. Wherever you find shear zones at South Pass, you usually find quartz stringers, quartz lenses, fractures, limited hydrothermal rock alteration and gold! So, take a look at Google Earth and scan from South Pass City (42°28'7"N; 108°48'10"W), to Atlantic City (42°29'46"N; 108°43'49"W), to the Miners Delight ghost town (42°31'60"N; 108°40'51"W) and place pins (placemarks) on mines, trenches and prospect pits. Not only will your fingers wear out placing pins in prospect pits, but soon you will visualize the trend of the shear zones. They form a northeasterly belt running along the western limb of the greenstone belt. If you do the same for the Lewiston district 11 miles to the east, you will see a similar pattern emerge.

The Duncan mine and mill, 1989

Parts of the South Pass greenstone belt are overlain by geologically young sedimentary rocks of Tertiary age (65 to 2.6 million years old) that include gold-bearing conglomerates in the Wasatch, White River, Arikaree, and South Pass Formations. When you prospect at South Pass, you will periodically see lenses of younger rocks scattered high and dry away from any known drainages - if they look like they have pebbles, cobbles, and boulders, dry pan them for gold. On past gold prospecting and geology field trips, I often stopped at one or two of these sites (42°28'45"N; 108°42’58"W) so prospectors could see another type of gold deposit found in the greenstone belt that has been overlooked. 

The more I mapped South Pass, the more it was clear that only a portion of the greenstone belt was visible at the surface and large parts of the complex continued under younger sedimentary rocks to the north and south. Geophysical exploration and drilling by Hecla Mining Company discovered greenstone belt rocks under a thick layer of sedimentary rocks, 6 miles south of South Pass City. Hecla had an excellent gold target at that location that their geologist (Foster Howland) interpreted as a buried, sulfide-rich iron formation, but the drilling project was cut short due to a recession.

The Carissa mine was developed in an intensely folded and faulted structure known as a shear zone. The primary high-grade gold-

bearing shear structure is 1.5 to 80 feet wide. This high-grade zone is enclosed by a much larger, completely unmined, low-grade shear envelope that is as much as 1000 feet wide! The envelope is almost completely untested even though samples show potential for a major gold deposit! A 97-foot composite chip sample that I collected on the south side of the high-grade shear within this low-grade zone yielded 0.023 ounces per ton. Another 30-foot sample on the north side of the high-grade shear yielded 0.07 ounces per ton of gold! The remainder of the envelope (about 850 to 900 feet) remains untested!.

The Carissa ore deposit is structurally controlled and appears to represent a saddle reef deposit where high-grade gold is localized in fold closures and rehealed fractures similar to the Homestake mine. Geological evidence suggests the Carissa orebody continues to great depth. Support for the presence of a major ore deposit includes drilling that tested the mineralized shear below the mine workings. Drilling by Consolidated McKinney Resources identified a highly anomalous zone that was up to 80 feet wide. Assays of drill core from this zone ranged from 0.03 to 2.54 ounces per ton gold (the shear envelop was not tested). This mineralized structure was intersected at depths up to 930 feet. In addition, Carissa Gold Inc. made the following reserve estimates on the property using a very high reserve cutoff grade. They reported the mine had 208,000 tons of ore with an average grade of 0.343 ounces per ton and a geological reserve of 37,000 tons of ore averaging 0.85 ounces per ton!

Anaconda Minerals also drilled the property and all of their reported drill holes interested ore grade material. They intersected a high grade ore zone over widths of 2.3 to 16.1 feet that yielded 0.11 to 0.36 ounces per ton gold at depths up to 700 feet. Again, they also ignored the shear envelop, which likely contains considerable gold that is minable at today’s gold prices.

In this region near Oregon Buttes (42°15'19"N; 108°51'21"W) and Dickie Springs (42°18'30"N; 108°51'48"W), Wasatch Formation conglomerates are estimated to be 1,300 feet thick and cover 8 mi². Some gold-bearing oil well cuttings were recovered from depths of 6,500 to 7,000 feet just north of the Continental Fault to the north of Oregon Buttes. This vast gold-bearing paleoplacer has been mostly ignored for decades, except at the Dave Freeman prospect, where Dave has been recovering gold from the dry placer. 

Erosion over millions of years left behind extensive Eocene paleoplacers along the north and south ends of the greenstone belt. One estimate by the US Geological Survey suggested the paleoplacers south at Dickie Springs and Oregon Gulch could contain 28.5 million ounces of gold! But the gold is distributed throughout a very large volume of conglomerate, and little to no standing water is available except at Dickie Springs. So, one either brings water to the conglomerate or vise versa. But just like any placer, these paleoplacers have pay streaks associated with black sands that contain magnetite, so a search using magnetic surveys may assist in identifying pay streaks.

Remains of the E.T. Fisher washing plant on Rock Creek. This mine operated from the 1933 to 1941. How good are your eyes?

 Can you see the beginning of World War 2 in this photo? It's pretty obvious. When WW2 broke out, all non-essential mines were

 ordered closed by the War Miners board - which included all gold mines. This placer operation on Rock Creek was still recovering

 commercial amounts of gold, when it was ordered to close. The mine (like many gold mines at that time) never reopened. Gold

 prices were $35.5 per ounce in 1941 as compared to $1,250 per ounce today. Few people have ever tried to reopen these old

 placer and lode gold mines that were ordered to close, even though they are almost guaranteed to be commercial. 

Learn as much as you can about shear zones: this is where the primary gold will be found. And, all of the good placer gold deposits are found a short distance downstream from shear zones. As you dig for placer gold in the drainages, keep in mind you will likely find pay streaks on false bed rock surfaces, with additional pay streaks on bedrock.

There are undoubtedly pay streaks downstream from many shear zones in the South Pass-Atlantic City-Miners Delight district and in the Lewiston district to the east. If I were to look for nuggets, I would examine places like Hermit Gulch (42°28'29"N; 108°47'23"W) since it is down slope from many good gold-bearing shear zones near the Carissa mine. Then there is Little Beaver Creek (42°29'26"N; 108°45'5"W) downstream from the Duncan, Mary Ellen and other mines. Spring Gulch lies downstream from the Miners Delight mine (42°31'55"N; 108°40’57”W) where many nuggets were found in the past and in the Lewiston district, there are several, small, immature, dry drainages downstream from shear zones. Most do not have much dirt, but that dirt likely has some gold. Some of these lie near a couple of shear zones that host the Goodhope (42°26'32"N; 108°32'22"W), Mint (42°26'32"N; 108°32’45”W), Gold Leaf and other mines that produced some excellent gold specimens in the 1980s and likely in the 1800s and early 1900s. The more you look around these shear zones, the more targets you will spot.

In the past, some of the better placer gold was collected on Rock Creek (I’ve seen over a hundred nuggets from the area) and Big Atlantic Gulch, and the better gold-bearing rock samples were collected at the Carissa mine (42°28'29"N; 108°47'42"W). So common was visible gold at the Carissa mine, that every field trip I led to the area, at least one person found a very attractive gold specimen on the mine dump. And I’m sure there were many I never heard about.

Hematite-stained quartz breccia with considerable visible gold in vugs
found at the Carissa mine. This became a common occurrence over
the years. Essentially every field trip the author led to South Pass
someone found specimens with visible gold. Most were found at
the Carissa mine. Other localities where visible gold in quartz was
 found included the Duncan, Miners Delight, Mary Ellen,
Good Hope, Mint and others

Based on assay samples taken at the Carissa mine (42°28'29"N; 108°47'42"W) by past mining companies and myself, a significant gold deposit continues along the Carissa-Duncan-Mary Ellen trend and down-dip for at least a thousand feet. At the Carissa, the mineralized shear zone is as much as a thousand feet wide. Past miners focused only on the high-grade gold in the narrow, prominent, shear structure, and completely ignored a very large envelope of low-grade gold. Past drilling showed the gold-bearing structure was mineralized to depths of 930 feet. This was the deepest any drill hole penetrated the gold structure - so, it could easily continue another 30 feet, 300 feet, 3,000 feet, or 30,000 feet. We don’t know. So, all of that gold-bearing rock from depths of 400 to 930 feet was never penetrated by the Carissa mine tunnels. And the low-grade envelope was left completely untouched from the surface to 930 feet. This same shear structure continues along strike for at least 1,000 feet before it narrows. Even so, the shear can be traced 8.5 miles from Willow Creek (42°27'49"N; 108°47'9"W) through the Carissa mine, and all the way to the northern edge of the greenstone belt near Meadow Gulch (42°32'4"N; 108°38'58"W) where it is buried by younger sedimentary rock.

In the mid-1980s, I applied for grants to map South Pass. The entire greenstone belt was wide open with no fences (except around the iron ore mine), and I often went for days, weeks and in some cases, an entire summer without seeing another person. But now there are more man-made structures and fences appearing in the belt. There is even a place called Rock Creek Hollow (42°26'25"N; 108°37'25"W) that didn’t exist when I mapped the greenstone belt. The Hollow has amphitheaters, fire pits, and even a parking lot with a bus turnaround. Near the end of my project, I was actually ran off the road by buses and a flatbed truck filled with portable outhouses. at this area. A barren hillside near this parade, sat a lemonade stand manned by women dressed like pioneers. It is clear that South Pass was changing, and my hope is that the area remains a gold-mining district and some of these people can learn to be friendly and share the road.

The Duncan gold mine and mill as it appeared to me when I first visited South Pass in 1978. I later detected significant gold in a

 distinct fold near the old glory hole. A 2.5 foot long channel sample yielded 0.96 ounce per ton gold!

During my project, I took one Saturday afternoon off to drive to the Mercantile in Atlantic City to have a beer and find out if the world still existed. I met a prospector who was looking for a place to pan for gold: I sent him to Strawberry Creek (42°26'1"N; 108°29'49"W) where he used a man-powered sluice with a hand shovel and managed to stay out of site of the BLM for a month. He was soon chased out of the area even though it was public land. In the fall, he stopped by my office at the University of Wyoming to tell me he had essentially filled his pockets with gold before being chased off of public land. These federal bureaucrats also need to learn to work with people and quit overstepping their bounds. After all, they work for us, not themselves.

Map of the Wyoming province showing locations
of Greenstone belts including South Pass.

As I mapped, I periodically took samples along various shear zones. I noted in between mines, outcrops and prospect pits, most of the shear zone structures were buried under a few inches to possibly a few feet of dirt. Potentially, more than 90% of the gold-bearing structures are hidden. If only I had a way to see through that dirt. Of course there was a possibility of using geophysics, but it would tell me what I already knew - there were miles of gold-bearing shear zones. But, I identified more than a hundred gold anomalies along these structures, and if I could have seen the buried structures, who knows what I would have found? This should give some prospectors some ideas on other placers to search for gold.

A couple of years ago I consulted on a gold placer project at Rock Creek, and it was clear that the 1930s dredging operation did a poor job, missed many areas, and lost a significant part of the gold where it mined. The operation was poorly designed, and even today, one can still find considerable gold (both fine and nuggets) in the dredge tailings.

While mapping, I found chips of rock with alteration characteristic of gold mineralization associated with shear zones elsewhere. These chips were found in the Crows Nest area (42°29'17"N; 108°36’43"W) of the greenstone belt. A short time later, a prospector (Gary Nunn) found several, nice, jewelry grade gold nuggets in the area using a metal detector. So, the Crows Nest also contains hidden shear zones that remain mostly untouched. 

Then there is Willow Creek - likely a very rich placer. But, the state government closed much of this creek to prospecting because it is reportedly filled with mercury! But, there is no known natural source for mercury in the belt; and if there is mercury in the stream, it was accidentally dumped by 19th century mining operations at the Carissa mine, and by now much of it would have worked its way to bed rock and be out of reach of most placer miners. Even more important, if there really is much mercury, it is a finite source that would soon be cleaned up by placer miners. Most of Willow Creek is unprospected and has limited dredge tailings (42°27'49"N; 108°47’9"W).

Many field trips to South Pass were led by the GemHunter to educate the public 

on gold prospecting. These trips were free to the public

Some placers at South Pass contain significant coarse gold. XL Dredging mined portions of Big Atlantic Gulch in about 1910 and recovered nuggets weighing 0.07 to 1 ounce. The ET Fisher Company dredged Rock Creek from 1933 to 1941 and produced 11,000 to 30,000 ounces: 75% of the gold was found within 3 feet of bedrock. Some of the gold was coarse and many nuggets were recovered. Nuggets recovered from Rock Creek include many small nuggets and some large nuggets as well as a boulder that reportedly had 630 ounces of gold.

After five years of mapping, I produced eight 1:24,000 scale geological maps - these should still be available at the Wyoming Geological Survey. I also produced a regional 1:50,000 scale geological map for the pocket of my 129-page book on South Pass published in 1991. This book should be available at the Wyoming Geological Survey. Along with these, I published dozens of books, papers, abstracts and tour guides on South Pass to assist mining companies and prospectors on where to find gold in this region (a partial list of my bibliography is available on my website at http://GemHunter.webs.com), and I wore out a tent, two pairs of field boots, and nearly a dozen tires. It was a dream come true and I feel blessed that I was able to spend so much time at South Pass, meet so many interesting prospectors and few scam artists.   

One of the locals at South Pass

REFERENCES

Hausel, W.D., 1991, Economic geology of the South Pass granite-greenstone belt, Wind River Mountains, western Wyoming: Geological Survey of Wyoming Report of Investigations 44, 129 p.

Hausel, W.D., 1993, Mining history and geology of some of Wyoming's metal and gemstone districts: Wyoming Geological Association Jubilee Anniversary Field Conference Guidebook, p. 39-63.

Hausel, W.D., 1997, The Geology of Wyoming's Copper, Lead, Zinc, Molybdenum and Associated Metal Deposits: Geological Survey of Wyoming Bulletin 70, 224 p.

Hausel, W.D., 2014, A Guide to Finding Gemstones, Gold, Minerals and Rocks: GemHunter’s Books, Amazon, 368 p. 

Hausel, W.D., and Hausel, E.J., 2011, Gold - A Field Guide for Prospectors and Geologists (Wyoming Examples), Self Published, Amazon, 366 p. 

Hausel, W.D., and Hull, J., 1990, Guide to gold mineralization and Archean geology of the South Pass greenstone belt, Wind River Range, Wyoming, in Roberts, S., Geologic field trips to western Wyoming: Geological Survey of Wyoming Public Information 29, p. 178-191.

Hausel, W.D., 1994, Mining history of Wyoming's gold, copper, iron, and diamond districts: Mining History Association 1994 Annual, Reno, Nevada, p. 27-44.

Hausel, W.D., and Love, J.D., 1991, Guide to the geology and mineralization of the South Pass area, in S. Roberts, editor, Mineral Resources of Wyoming: Wyoming Geological Association 42nd Annual Field Conference Guidebook, p. 181-200.

Snyder, G.L., Hausel, W.D., Klein, T.L., Houston, R.S., and Graff, P.J., 1989, Precambrian rocks and mineralization, Wyoming Province: 28th International Geological Congress guide to field trip T-332, July 19-25, 48 p.

A portion of the Radium Springs Quadrangle by the author, showing rocks, mines, veins,
Laramide faults, and shear zones. 

Simplified map of the Lewiston gold district

Simplified geological map of the South Pass-Atlantic City district.

Tailings along Rock Creek, Wyoming

Gold at South Pass Wyoming

Visible gold in amphibolite from South Pass. 

Reconstructed head frame at the Carissa Mine at South Pass
(Photo taken during field trip in 2010).

SUMMARY
Every year for 29 years, one geologist at the Wyoming Geological Survey (W. Dan Hausel) volunteered time to lead free field trips for the public and geological associations to teach them about geology & gold & diamond prospecting methods, gem-hunting and methods used to find new gold deposits. He was in high demand for talks to prospecting groups, mineralogical associations, business organizations and geology federations throughout the country.

In his office in Laramie at the University of Wyoming, he met with hundreds of visitors and prospectors and identified rocks and minerals for the general public and mining companies. Over the years, hundreds of books, documents and maps on geology were published and Hausel was presented national and international awards for research.

SOUTH PASS - LAND OF GOLD and IRON
Very little modern research was conducted at South Pass, until this geologist (Dan Hausel) mapped the greenstone belt and identified hundreds of gold anomalies and produced eight 1:24:000 scale maps of the geology and 1:48,000 scale summary geological map and several 1:120 and 1:240 geological maps of accessible underground mines.

The South Pass greenstone belt produced nearly all of the known historical gold in Wyoming, yet it remained mostly unmapped until the 1980s and early 1990s, when the entire greenstone belt and all accessible underground mines were mapped and hundreds of samples were collected for assay, geochemistry and mineralogical studies. .This resulted in several publications culminating with a report on the greenstone belt and its mining districts (Hausel, 1991). It was clear that considerable gold remained unmined and very little modern exploration was conducted in this region other than a few, piecemeal drilling and trenching studies due to the investigations by Hausel (1991).

Some mysteries that remained to be resolved was how extensive was the Carissa ore deposit,, which appears to have potential to be a multi-million ounce deposit, how extensive was the Miners Delight, Duncan, Diana, Tabor Grand, Wolf and other significant mines. Additionally, how much placer and eluvial gold have been missed by earlier prospectors. At least one diamond was reportedly found in this belt, thus was there potential for diamonds in this region?

Other problems that remain to be resolved include the sources of the giant Oregon Buttes and McGraw Flats paleoplacers. The Oregon Buttes paleoplacer appears to be mostly eluvial with some reworking into modern placers at Dickie Springs.

The closure of areas by the State and Federal government based on very sketchy data is of great concern. In particular, the closure of the Willow Creek placer, which is likely a major gold deposit, is purportedly filled with mercury from a mysterious source. There are no known natural sources for mercury in this region, and the introduction of so much mercury by mankind is highly unlikely: the environmental data is likely flawed. This placer along with the significant gold mineralization at the Carissa mine was withdrawn by the State of Wyoming and should be made available to the taxpayers rather than kept in government holding.

While exploring the surface and underground workings at the Carissa mine along with drilling by mining companies, it was more than apparent that a major, untapped gold deposit remained. Evidence of commercial gold was found throughout the surface workings over a minimum of 1000 by 980 feet as well as to depths of 970 feet. BUT, the mineralization was open in every direction and undoubtedly continues hundreds of not thousands of feet below the mine workings.

Placer gold from Smith Gulch at South Pass - about 20 ounces recovered
in a week by Buddy Presgrove and Hank Hudspeth. 

On the 350-foot level at the Carissa mine. Steve Gyorvary stands in mined out stope to provide scale of size of the primary shear (look for his mine lamp). All of the open space that Steve is standing in is the former gold-bearing shear structure that was mined out. This structure continues 350 feet to the surface; another 640 feet beneath this level (based on drilling) and likely a few thousand feet deeper.

It also continues along strike (trend) for a minimum of 1,000 feet and is enclosed in a envelope shear that is about 1,000 feet wide. This could have been one of the great gold deposits of Wyoming. But the Wyoming legislature supported its purchase by the state, withdrawal and placed the property within Wyoming's version of a Disneyland at the South Pass City historical site. One should ask why their taxes are being used to purchase economical gold mines and reconstructing historical facilities. This property could have been developed, mined and reclaimed then donated to the South Pass City historical site instead of taking the mine from the public as well as a major gold resource, jobs and a tax base.

For example, the primary shear structure has a average gold grade of 0.15 to 0.3 ounces per ton based on sampling, mining and drilling. For comparison, properties currently being mined in Nevada yield average ore grades of 0.03 to 0.15 ounces per ton. The Carissa shear has one of the highest average gold grades for a gold mine in North America. This primary shear is enclosed by a larger low-grade shear zone that is as much as 1000 feet wide and much of it is unexplored but it yielded gold values of 0.01 to 0.09 ounce per ton where it was sampled.

The development of the Carissa mine would have led to other exploration and likely development of other properties. Unlike other greenstone belts in Canada and Australia, the shear zones at South Pass remain relatively unexplored and it is estimated that only about 5% of the exposed shears have been sampled and tested for gold!

Steve Gyorvary poses on the 350 foot level
of the Carissa mine (photo by W. Dan
Hausel). 

FIELD TRIP TO SOUTH PASS

In 2004, >100 prospectors, members of the general public, and 8 dogs (considered to be first class rock hounds) toured South Pass. For Hausel, this area has special meaning as he spent 5 field seasons living in a tent in South Pass in order to map the 450 mi2 granite-greenstone belt along with 3 dozen underground mines. While all other state employees received full per diem to cover food and lodging, the WGS allowed Hausel to use his personal tent and refunded the cost of groceries. The last two mapping seasons, he was provided a government tent.

South Pass was Wyoming’s principal gold district, and could potentially produce significant amounts of gold and iron ore again – not to mention the possibility of finding colored gemstones and diamonds. Both aquamarine and a diamond have been reportedly found in the district in the past.

During mapping hundreds of gold anomalies and some iron ore resources were identified and/or discovered. The project resulted in the mapping and sampling of several gold-bearing structures that could potentially host some very large gold deposits – by far the best of these, based on sampling and mapping is the Carissa mine near South Pass City. The Carissa mine could easily represent a Million plus ounce gold deposit.

HISTORY
According to historical records, the first report of gold at South Pass was made on Strawberry Creek as early as 1842 by a trapper from the American Fur Company. Several years later (in 1855), a group of 40 prospectors entered South Pass to follow up on the discovery and reported gold nearly everywhere at South Pass. This expedition was followed by a group of 9 prospectors who returned to the area in 1858 and commenced mining on Strawberry Creek. The decayed remains of their sluices were later found in 1870.

In 1861, another expedition to South Pass included a group of 52 prospectors who began mining on Willow Creek, when they were attacked by Indians and driven out. Two years later (1863), gold was discovered on the Oregon Trail immediately south of South Pass in the vicinity of Oregon Buttes (Oregon Buttes was studied more than a century later by the US Geological Survey, and is now recognized as one of the largest undeveloped gold occurrences in North America - the source of the gold is thought by some to be the South Pass greenstone belt).

Oregon Buttes from South Pass includes a giant gold  paleoplacer and placer. The paleoplacer (the ridge in the
lighted area on the horizon below Oregon Buttes) was  suggested by the US Geological Survey to host >28.5 million
ounces of gold, making it one of the larger undeveloped gold deposits in the US. The source of the gold for Oregon
Buttes has never been identified but in all probability lies at depth beneath the sedimentary cover and eroded from the
greenstone belt hidden under those younger sedimentary rocks. Drilling by Hecla Mining Company verified
the presence of the greenstone belt under the sedimentary rocks;and identified what may be a hidden, gold-bearing sulfide-rich iron formation at depth.

In June 1867, the richest lode in the district was discovered that is currently known as the Carissa. These miners were attacked by Indians, three were killed and the rest were driven out, but returned later in late July. In the winter of that year, 400 ounces of gold were recovered from the lode using very primitive tools. Four 4 tons of ore were shipped to Springfield, Utah a short time later, which yielded an incredible 1,400 ounces of gold!

Because of the continual hostilities between the Whites and Indians, the US Army established Camp Stambaugh near the towns of Atlantic City and Miners Delight in 1870. However, many of the recruits deserted to search for gold.

View of the primary, high-grade gold-bearing shear zone at the Carissa mine.
Note the geologist (Jon King) for scale. 

The Carissa mine (see photo to left) was Wyoming’s principal gold mine & produced more than 180,000 ounces of gold (worth about $300 million at today's gold prices) based on incomplete production records. Missing production records over a period of several years suggest that the gold production could have been considerably more. Mapping by Hausel and drilling by various companies indicates that a sizable gold resource remains unmined. However, the mine was incorporated into the South Pass City historic site.

By 1872, 12 stamp mills were operating in the district. In 1878, the Army abandoned Camp Stambaugh, even so, the Oregon Trail had to be abandoned for a safer route to the south due to increased hostilities. South Pass continued to be a battle ground until 1882 following the signing of the Treaty of Five Nations.

In 1884, significant placer operations were proposed and the Granier ditch was constructed to haul water from Christina Lake (12 miles away) to South Pass. Start up of the hydraulic operation did not occur until 1890. In 1891, 6,720 ounces were recovered from the operation. Today, scattered and sporadic prospecting operations continue to produce minor amounts of gold. However, the South Pass district hosts significant hidden and exposed gold deposits – nearly all are unevaluated. For example, the shear zone structure at the Carissa Mine may host a very sizable gold deposit based on geology and sampling. The Carissa shear zone. The Carissa mine was developed into an intensely folded and faulted structure known as a shear zone. The primary shear structure containing high-grade gold is 1.5 to 80 feet wide. This high-grade ore shoot is enclosed in a major shear envelope that is as much as 1000 feet wide!!! This envelope is almost completely untested even though samples show potential for a major gold deposit! A 97-foot composite chip sample taken on the south side of the high-grade shear yielded 0.023 ounces per ton. Another 30-foot sample taken on the north side of the high-grade shear yielded 0.07 ounces per ton of gold! Thus the remainder of this envelope (about 850 to 900 feet) remains untested!.

The Carissa ore deposit is structurally controlled and appears to represent a saddle reef deposit where high-grade gold is localized in fold closures and rehealed fractures similar to the Homestake mine. Thus geological evidence suggests that the Carissa ore body undoubtedly continues to great depths. Support for the presence of a major ore deposit includes drilling that tested the mineralized shear below the mine workings. Drilling by Consolidated McKinney Resources identified a highly anomalous zone that was up to 80 feet wide. Assays of drill core from this zone ranged from 0.03 to 2.54 ounces per ton gold (the shear envelop was not tested). This mineralized structure was intersected at depths up to 930 feet. Based on similar deposits in other greenstone terrains around the world, it is likely that the deposit continues to depths of 2,000 to 10,000 feet. In addition, Carissa Gold Inc. made the following reserve estimates on the property using an extraordinary high reserve cutoff grade. They reported 208,000 tons of ore that had an average grade of 0.343 ounces per ton and a geological reserve of 37,000 tons of ore averaging 0.85 ounces per ton!

Anaconda Minerals Company also drilled the property and all of their reported drill holes interested ore grade material. They intersected a high grade ore zone over widths of 2.3 to 16.1 feet that yielded 0.11 to 0.36 ounces per ton gold at depths up to 700 feet. There are many unknowns about this mine, but it is clear that the Carissa is a viable exploration target for gold that could potentially host a very sizable, untapped gold deposit!


GREENSTONE BELT & GEOCHRONOLOGY

The attendees of the field trip learned that South Pass is a fragment of a larger greenstone belt. Greenstone belts are found at a number of places worldwide including Canada, Australia, and Africa where a very large percentage of the world’s gold is produced.

The term greenstone belt is often considered to be synonymous with the phrase Gold Belt. This is because most greenstone belts are important sources for significant amounts of gold as well as other metals including iron and nickel, and gold anomalies have been detected over very large areas of the South Pass greenstone belt. In particular in a distinct belt running from South Pass City, through the Carissa mine, through Atlantic City and to the Miners Delight mine over a belt of more than 6 miles in length.

At the Miners Delight mine a 3 to 16 foot wide shear zone was traced over 2500 feet on the surface. Gravels in Spring Gulch draining this shear zone produced 1500 ounces of gold including several 1 ounce, >2 ounce nuggets, a 6 oz nugget, and a sample of auriferous quartz described as “the size of a water bucket that was filled with gold”. Samples collected across the shear zone by Hausel ranged from 0.01 to 0.36 ounce per ton gold. A historic prospectus reported that there were 2,400 feet of drifts accessed from a 250 foot deep shaft and that the mine produced 60,000 ounces and that the gold tenor ranged from 0.3 to 110 ounces per ton of gold. Little is known about the mine.

View of the Duncan mine - Gold was detected in
a fold nose by the author. A 2.5 foot channel
sample assayed 0.96 opt Au. Such a sample likely
had some visible gold.

Several mines along this belt contain anomalous gold. The Duncan, Mary Ellen, Tabor Grand, St. Louis, and Diana are some of the better known mineralized properties and mines. Common specimens containing visible gold attest to their potential.

All of the drainages downstream from this belt have produced significant placer gold. Another parallel belt (about 4 miles in length) occurs in the Lewiston area. During geological mapping of the greenstone belt, Hausel also identified rock significant alteration that is characteristic of gold mineralization in the Crows Nest area between these two mineralized belts. In addition, the greenstone belt continues under rock to the northeast as well 6 miles to the south of South Pass City. It is notable that both of these regions are overlain by giant gold paleoplacers (McGraw Flats-Twin Creek to the north, and Oregon Buttes to the south) suggesting the presence of at least two major hidden gold deposits.

The rocks at South Pass are old! South Pass is an Archean (older than 2.5 billion years) greenstone belt. Gneiss in the early crystalline complex of the Wind River Mountains yields Rb-Sr dates of 2.8-3.8 Ga (billion years old), and granitic rocks of the Louis Lake Batholith (which intrude the greenstone belt) yield dates of 2.6 Ga. A Rb-Sr isochron for the Miners Delight Formation within the greenstone belt yielded a 2.8 Ga date. This latter age may represent a prograde metamorphic event, and the rocks could be older. One model lead date from the Snowbird vein at the Snowbird mine of 2.8 Ga, may suggest a temporal connection between metamorphism and mineralization.

STRATIGRAPHY OF THE GREENSTONE BELT

The Mary Ellen mine (1989

Nearly everything that is known about the geology of the South Pass greenstone belt is due to the work of Hausel over a period of several years. Mapping showed that only a portion of the South Pass greenstone belt synform is preserved at the surface. Geophysical exploration and drilling by Hecla mining to the south supported that the greenstone belt continues under young sedimentary rocks to the south for at least 6 miles.

At the base of the South Pass synform (basin) gneiss referred to as an S-type gneiss complex, or the basement of South Pass, is interleaved with the Diamond Springs Formation, the oldest member of the South Pass greenstone belt. The Diamond Springs Formation consists primarily of primitive metamorphosed igneous rocks that include distinct peridotites with MgO contents ranging from 18 to 38%; chromium from 600-10,000 ppm (parts per million); and nickel from 160-2600 ppm. The CaO/Al2O3 ratios for these rocks are low (0.06-2.8) and they posses flat REE (rare earth element) patterns similar to komatiites. Thus these rocks are thought to represent primitive mafic and ultramafic basalts and komatiites (in other words, very high magnesium volcanic rocks).

The Goldman Meadows Formation overlies the Diamond Springs Formation. These rocks include thick banded iron formations along with mica schists and quartzite. The average iron content for the iron formations is upwards to 40%, and a sizable resource is still present. In the past, US Steel Corporation operated a large open pit mine (Atlantic City mine) and recovered more than 90 million tons of iron ore prior to the closing of the mine in 1983. Even so, mapping suggests that at least 300 to 400 million tons of iron ore remain in place. The geology of the Goldman Meadows formation suggests that it was deposited in shallow water on a stable platform and was shed from a nearby shelf.

A 7.5 ounce nugget found on Rock Creek

The Goldman Meadows Formation is overlain by the Roundtop Mountain Greenstone. The Roundtop Mountain Greenstone consists primarily of thoeiitic oceanic basalts that in places have well preserved pillow structures. One of the more popular stops on the South Pass field trips is overlooking the iron ore mine where some excellent pillow basalts are preserved under the power line.

The Roundtop Mountain Greenstone is overlain by the Miners Delight Formation, which is estimated to be 5,000 to 20,000 feet thick. Determination of the thickness of this unit is complicated because the entire belt has been intricately folded and faulted almost like an accordion. This formation consists primarily of metagraywacke that contains a trace to 0.051 ppm Au (gold) (compared to average of 0.002 ppm). Essentially all of the rock units at South Pass exhibit above average gold content and are interpreted to have been deposited in a moderately deep oceanic basin. However, the spatial association of proximal facies metagraywacke with meta-andesites near Miners Delight suggests that there was also a contribution from an Archean age island arc. Portions of the South Pass greenstone belt are overlain by Tertiary age, gold-bearing conglomerates in the Wasatch, White River, Arikaree, and South Pass Formations. It is obvious that South Pass is highly anomalous in gold!


GOLD GEOCHEMISTRY

The gold geochemistry was studied by the US Geological Survey. The Au/Ag ratios are high & Au/Cu ratios are low for some of the gold at South Pass. The trace metal contents (Bi, Pb, As, Sb, V, Mo, W, B, Nb, Zn, Cr, Co, Ni) are typical of hypothermal veins in other greenstones worldwide. Stable isotopes and fluid inclusion studies support that the South Pass gold is similar to that of a hypothermal vein system. The carbon and oxygen isotopes in shear zones along with hydrogen isotopes from fluid inclusions support that the much of the gold solutions were derived from the dewatering of the Mineral Delight Formation during compaction.

Structurally, the major gold systems at South Pass are located adjacent to a distinct group of metagabbos, metatholeiites, and actinolite schists (metakomatiites) that trend from South Pass City to Miners Delight. The localization of gold in this region is believed to be due to competency contrasts between the metagabbros and adjacent Miners Delight metagraywackes. During folding, it is thought that these were favorable for the development of numerous fractures and faults. Much of the ore is found in these shear structures contain enriched ore shoots developed in folds suggestive of a reef-type structural control. Placers downstream from the shear structures are highly enriched in gold.


PLACERS

Nuggets recovered from the Crows Nest at South Pass by Gary Nunn. Above photo is visible gold in quartz found by
Steve Gyorvary

Gold from dredge tailings on Rock Creek from Gerald Stout 

(photo by Hausel). It is interesting to note that the last dredge 

that operated in Rock Creek terminated operations 

because of world war II, not because they ran out of gold. 

If the placer was commercial at $35/ounce of gold - one 

would anticipate that it is still commercial at $1900/ounce. 

And what about the parallel Willow Creek that drains 

off of the Carissa mine to the south of Rock Creek? 

It has much less gravel, but possibly is much richer in gold. 

It remains unmined due to state withdrawal. Based on today's gold

price, the Rock Creek placer produced more than $115 million

Some of the placers at South Pass contain significant coarse gold. For example, XL Dredging mined portions of Big Atlantic Gulch about 1910 and recovered nuggets weighing 0.07 to 1 ounce. The ET Fisher Company dredged Rock Creek from 1933 to 1941 and produced 11,000 to 30,000 ounces: 75% of the gold was found within 3 feet of bedrock. Some of the gold was coarse and several nuggets were recovered. Nuggets recovered from Rock Creek include many small nuggets and some large nuggets.

Boulders containing as much as 630 ounces of gold were also reported in the historical record. Much of this coarse gold was found during dredging of various drainages.

PALEOPLACERS

A 34 ounce gold nugget from Rock Creek!

Gold paleoplacers (old dry placers) cover large areas at South Pass. The paleoplacers have been studied primarily by the US Geological Survey. These are found within and on the edge of the greenstone belt. For example, one paleoplacer sits immediately south of Atlantic City in the South Pass Formation. This gold-bearing paleoplacer remains unevaluated.

At Oregon Buttes, the Wasatch Formation conglomerates are estimated to be 1300 feet thick and cover 8 mi2 and to host a major gold resource estimated to be as high as 28.5 million ounces (US$30 billion). Some gold-bearing oil well cuttings were recovered from depths of 6500-7000 feet just 0.5 mile north of the Continental Fault adjacent (north) of Oregon Buttes indicating the presence of a buried auriferous shear zone at that location. Geophysical exploration in this area by Hecla Mining Company identified what appears to be a iron formation (at depth). Hecla interpreted this to be a gold-bearing iron formation. The paleoplacers at Oregon Buttes have been reworked producing some enriched dry placers.


SUMMARY

All of the field trip attendees had a good time in the sun and learned about the mining history and methods used to find gold. Many of them also became aware of the tremendous gold potential of this district and the possibilities that some mines and some high-paying jobs could result from exploration and development in this region. One should note that this district is still only in its infancy for exploration and it is estimated that only about 5 to 10% of the shear structures have been sampled. This means that dozens of rich ore shoots are likely hidden under a few inches to a few feet of dirt and eluvium.

Hausel (right) talks about gold at the Carissa shear zone. Based on sampling, mapping, and drilling, the Carissa property is probably one of the better gold targets in Wyoming and potentially in the West. Hausel is the author of more than 50 professional papers, books and maps on South Pass.

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RECOMMENDED READING

• Hausel, W.D., 1989, The geology of Wyoming's precious metal lode and placer deposits: Geological Survey of Wyoming Bulletin 68, 248 p.

• Hausel, W.D., 1991, Economic geology of the South Pass granite-greenstone belt, Wind River Mountains, western Wyoming: Geological Survey of Wyoming Report of Investigations 44, 129 p.

• Hausel, W.D., 1993, Mining history and geology of some of Wyoming's metal and gemstone districts: Wyoming Geological Association Jubilee Anniversary Field Conference Guidebook, p. 39-63.

• Hausel, W.D., and Hull, J., 1990, Guide to gold mineralization and Archean geology of the South Pass greenstone belt, Wind River Range, Wyoming, in Roberts, S., Geologic field trips to western Wyoming: Geological Survey of Wyoming Public Information 29, p. 178-191.

• Hausel, W.D., 1994, Mining history of Wyoming's gold, copper, iron, and diamond districts: Mining History Association 1994 Annual, Reno, Nevada, p. 27-44.

• Hausel, W.D., and Love, J.D., 1991, Guide to the geology and mineralization of the South Pass area, in S. Roberts, editor, Mineral Resources of Wyoming: Wyoming Geological Association 42nd Annual Field Conference Guidebook, p. 181-200.

• Hausel, W.D., and Love, J.D., 1991, Guide to the geology and mineralization of the South Pass area: Wyoming State Geological Survey Reprint 49, 20 p.

• Snyder, G.L., Hausel, W.D., Klein, T.L., Houston, R.S., and Graff, P.J., 1989, Precambrian rocks and mineralization, Wyoming Province: 28th International Geological Congress guide to field trip T-332, July 19-25, 48 p.


Also, see our websites at: GOLD

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GOLD - Geology, Prospecting & Exploration






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Look what our trammel dredged up! The GemHunter stands in the middle