Friday, December 7, 2012

Kimberlite Pipes and Volcanoes

Would you like to see a kimberlite volcano erupt? Me too! Watch the following animation:

KIMBERLITE PIPE eruption.

And here is another interesting video on the Internet.

ARCTIC STAR 3D KIMBERLITE ANIMATION  Very nice!


And below are some photos of kimberlites, diamonds, books, etc.

High wall with exposed diamond-bearing kimberlite breccia at the Kelsey Lake mine, Colorado. If you have Google Earth on your computer, search for 'Kelsey Lake, Colorado' to see the location of this former diamond mine.

Diamond-bearing Schaffer kimberlite dike Wyoming, that was exposed in dozer trench in 1979 or 1980. Jay Roberts, geologist, stands in the trench, for scale. The kimberlite is the gray-blue material. The reddish material in the foreground is sheared Proterozoic granite (Sherman granite facies).

Diamondiferous kimberlite from the Sloan 2 pipe in Colorado.   Note the large, rounded pyrope garnet.  The Sloan kimberlites have identified diamond resources and remain mostly untouched. DiamonEx had acquired the Sloan property, but the 2008 economic collapsed took its toll on diamond prices, the company, and the world. So, it still holds $millions in diamonds.

Kimberlite (Devonian) and Granite (1.4 billion years old) contact exposed by bull-dozer, Schaffer
kimberlite complex, Wyoming.

Maxwell diamondiferous kimberlite in Colorado - one of many kimberlite pipes and dikes in Colorado and Wyoming that still remains untested for commercial diamonds. Diamonds were recovered from a small sample from this pipe (C.D. Mabarak, personal communication).

Buried kimberlite dike in Wyoming - the kimberlite underlies the dirt in the right half of the photo where there appears to be thicker and slightly higher vegetation.

Diamonds in the US?  From Diamonds and Mantle Source Rocks in the Wyoming Craton - by W. Dan Hausel, 1998. The diamond-shaped figures represent reported diamonds. The triangles are kimberlite localities (open triangles are diamond-bearing kimberlites), squares are high-pressure volcanics similar to kimberlite, + are lamprophyres and lamproites, the + enclosed by a diamond is diamond-bearing lamproite, the white diamond is the location of the Great 1872 Diamond Hoax site, the dots represent kimberlitic indicator mineral anomalies of note.

Some of the high-quality gem diamonds from Kelsey Lake mine (photo courtesy of Howard Coopersmith).

Close-up of diamond surface with some of the distinct trigons etched in the surface.

Popular book (129 p) on diamonds in the US - you might be able to buy this at the Wyoming Geological Survey at the University of Wyoming. 



Book on rocks and minerals that also has some brief information on diamonds and on kimberlite and lamproite. Available at  Amazon


Another popular book on gemstones (and diamonds) that the Wyoming Geological Survey forgot to reprint after the current edition was sold out. 
Gem-quality kyanite from central Laramie Mountains (we found billions of carats of this gem - but it remains undeveloped). Some of this gem is found with iolite, ruby and sapphire in the central Laramie Mountains.




Free pamphlet on diamonds - this may still available in Wyoming.  If not, you can download a copy at the  GEM HUNTER website.
Rough diamond from Wyoming - wow, aren't these stone beautiful! Note how the gem has kind of a greasy luster. This is characteristic of diamond.


Exploration methods for kimberlite - this was one of the first diamond publications I published. I was excited about the publication and the work I did. For me, this was the perfect job with imperfect wages. But what the heck, you can't have everything.

Recent publication on geology of the Leucite Hills lamproites and possibilities of diamonds in the Leucite Hills lamproites in Wyoming (may or may not be available at the Wyoming Geological Survey).  I loved  working in this area. While conducting research on diamonds, we recovered diamond-stability chromites from some of the lamproites (this suggests the chromites formed under pressures and temperatures similar to that of diamond formation; thus there is a possibility for diamonds in this region).

Essentially all of the projects at the Wyoming Geological Survey were considerably underfunded and so was this one. Even though these rocks may contained diamonds, we were unable to test any material (other than a couple of rocks). Elsewhere in the world, there is a correlation between olivine and diamond content in some lamproites, so I was excited to find a couple of anthills with considerable olivine in the northeastern portion of the Leucite Hills. After looking at some olivine with a handlens, it was apparent nearly all was gem-quality. So I took the two anthills in sample bags - and Robert Gregory processed the material (no diamonds were found), but we recovered 13,000 carats of gem-quality peridot from this sample!

Diamonds in the world - great book, but price is too high (don't blame me, I receive no royalties for this book and the publisher ignored our protests about the price - 374 pages.

Book  (42 pages) on a little known diamond-bearing kimberlite district in Wyoming. We didn't find any diamonds (found lots and lots of diamondbacks) - nor did we test any material for diamonds. However the geochemistry of all of the rocks showed that they all originated from the diamond-stability field and a couple of diamonds were reportedly found in the early 1980s by Cominco American.


Ruby from Granite Mountains, Wyoming. Specimen found by Eric Hausel.
Kimberlite 'diamond' Indicator minerals. These include pyrope garnet, spessartine garnet, pyrope-almandine garnet, emerald-green chromian diopside, picroilmenite (black metallic with white leucoxene crust) and two tiny black, octahedral chromites. Here is an example of how geologists miss gemstones. These were all recovered from the Sloan 2 kimberlite in Colorado when I was working for DiamonEx Ltd. Everyone working in this region for years focused only on the diamonds; yet these are all gemstones and can be faceted into beautiful colored gems while the chromites and picroilmenites could be fashioned into low-value gem cabochons.


Guide to finding gemsgold, diamonds and rocks in Wyoming. If you can't find it at the Wyoming Geological Survey, you can download a copy from the GemHunters website.

There are many gemstones in Wyoming. Most people would have laughed if you told them in 1975 that Wyoming had the greatest variety of gemstones in the US. In 1975, Wyoming had known jade deposits and some agates - but that was about all.

Over three decades, the more I looked, the more I found: dozens of overlooked gemstone deposits and evidence for hundreds more which included commercial gold deposits along with more than 100 gold anomalies.  It was my intention to continue this research along with educating the public to help YOU find gemstones, diamonds and gold using methods I found successful in finding a few hundred mineral deposits.

But morally and ethically, I could no longer work for the Geological Survey or the State of Wyoming, so I moved on. Since 2006, there have been no discoveries of new metal or gemstone deposits.

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Thursday, August 18, 2011

Colorado, Montana, Wyoming - a major diamond province remains overlooked

North American Craton with Wyoming Craton

Aerial photo over Twin Mountain Lake anomaly
A few of the Twin Mountain Lakes cryptovolcanic structures.
Note the white carbonate on the shoreline.


Hundreds of kimberlites, lamproites, lamprophyres, diamonds and cryptovolcanic structures have been identified  in the Wyoming Craton that lies under portions of Colorado, Kansas, Montana and Wyoming. Some of the larger targets were discovered in the Twin Mountains Lake district adjacent to I-80 between Cheyenne and Laramie by the author several years ago, and these remain unexplored. More than 50 cryptovolcanic depressions show structural control, carbonate-rich sediments (in an Archean crystalline terrain) and distinct depressions adjacent (east) of the State Line diamond district. These could potentially be kimberlites with untold amounts of diamonds.

Some Wyoming diamonds
To view these anomalies (some may represent some of the larger diamond pipes in North America) search Google Earth "Twin Mountains, Cheyenne West, WY 82059". I highly recommend that you also examine these on Virtual Earth in the Twin Mountains Lake - Twin Mountains area.

Excellent diamond showing classical trigons on the surface of the diamond

Saturday, November 22, 2008

Major Diamond and Colored Gemstone Deposits Found in US

MAJOR DIAMOND PROVINCE DISCOVERED
see GEMHUNTER

See also http://DiamondProspector.webs.com
State Line Kimberlite Province showing locations of (1) Radichal kimberlite &
Mineral Indicator Anomalies, (2) the Iron Mountain kimberlite district, (3) Schaffer,
Aultman, Ferris kimberlites, (4) Keslsey Lake Kimberlites (5) Nix kimberlites, (6)
Sloan kimberlites, (7) Estes park kimberlites, (8) Boulder Kimberlite, (9) Boden
diamond placer. In between these are several hundred cryptovolcanic structures
with similarities to kimberlite pipes as well as more than 300 kimberlitic mineral
anomalies.



False-color aerial photo shows a few of the several hundred
cryptovolcanic structures that have been found in Colorado
and Wyoming. These structures are lake filled, structurally
controlled depressions with carbonate-rich soils
on shore lines. Are these just lakes? Or
are they diamondiferous kimberlites? Note the roads near
these structures to get an idea of scale.

Research suggests that the Wyoming Craton encloses a world-class diamond province as well as major deposits of colored gemstones. The Wyoming Craton includes portions of Colorado, Nebraska, Kansas, Montana , Wyoming, Alberta & Saskatchewan, & encloses the two largest known kimberlite districts in the US & the largest lamproite & lamprophyre fields in North America. Diamonds have been reported in kimberlites and lamprophyres in this craton in Canada, Montana, Wyoming, Colorado and Kansas.

Hundreds of kimberlites, lamproites and lamprophyres were identified over the past few decades. In addition the many known diamondiferous kimberlites & lamprophyres, in recent years, four significant iolite (water sapphire) deposits were found as well as deposits of ruby, sapphire, opal, kyanite gems, jade, chromian diopside (Cape Emerald), pyrope garnet (Cape Ruby), almandine garnet, spessartine garnet, peridot, gem-quality apatite, jasper, agate, onyx and other gems - all found since about 1975. Two of the iolite deposits are world class. This region has turned into an exploration geologists' and rockhounds' paradise.

Consulting geologist W. Dan Hausel identified hundreds of cryptovolcanic structures within this province over the past several years. Many are quite large and some are situated within known diamond districts and in large areas that remain unexplored. In addition to the the known kimberlite, lamproite and lamprophyre districts, more than a dozen new districts containing many cryptovolcanic structures were discovered. As incredible as it seems, a few lie adjacent to interstates and highways and have been missed by millions of travelers every year.

Cryptovolcanic structure (kimberlite) in Colorado showing open park associated with depression.
During the past 30 years, the two largest diamondiferous kimberlite districts in the US and the largest field of lamproites in North America were mapped in the Colorado-Wyoming region. Several hundred kimberlitic indicator mineral anomalies were also scattered all over Wyoming, parts of Colorado, Utah, Montana, Kansas and Alberta. Other researchers found similar anomalies.

The several hundred cryptovolcanic structures have characteristics that suggest most are kimberlite pipes. They are circular to elliptical in shape, structurally controlled, many are distinct depressions with distinct vegetation anomalies similar to kimberlites mapped in the past. Some of the depressions are so distinct that they have actually been mistaken as impact sites, such as the Winkler crater in Kansas, that was originally thought to be an impact site, and later discovered to be kimberlite, and a few depressions that were identified in the central Laramie Range and Medicine Bow Mountains. Field examination of many depressions show visible blue ground and carbonate-rich soil, with rounded boulders and cobbles –characteristics that are generally associated with kimberlite. In addition, samples from some sites yield the traditional kimberlitic indicator minerals.

Historically kimberlite pipes were described in 19th century South Africa as having ‘blue ground’, considerable calcium carbonate, and were thought to be old dry stream placers because they contained rounded cobbles and boulders (similar to the cryptovolcanic structures found in the Wyoming craton). The rounded boulders were instead due to country rock fragments that had been rounded and polished in the kimberlite magma as it erupted a few hundred million years ago.

Diamonds from Arkansas - photo
from Glenn Worthington
A few of these structures may represent some of the larger pipes in the world. The best explanation for most of these depressions is that they represent soft, circular deposits of rock that is dramatically different from the more resistant and harder basement granite and gneiss country rock they intrude. Kimberlite typically erupts in circular maar-like volcanoes and is a relatively soft rock. This is why so many kimberlites discovered in Canada as well as in the Wyoming craton form distinct open, treeless parks, with several being submerged under shallow ponds and lakes.

Such structures have been found in the Laramie, Medicine Bow, Front and Seminoe Mountains, the Green River Basin, Bighorn Basin, eastern Kansas, and Alberta. Several hundred were found as far south as Denver Colorado, to as far north as central Alberta, and as far west as Little America to as far east as eastern Kansas. In the vicinity of the Colorado-Wyoming border, Hausel mapped the State Line district with more than 40 diamondiferous kimberlites. Some of these form distinct circular depressions and have already be verified as diamond pipes.

Rough diamond with trigons
Unfortunately, only a few of the anomalies and the known kimberlites, lamproites and lamprophyres have been tested for diamond. But nearly all that have been tested yielded some diamonds. The State Line district alone produced more than 130,000 diamonds during testing in past years. No one really knows what awaits discovery here as past diamond testing was inefficient.

For example, the four diamond mills constructed to test various diamond deposits in the State Line district had many significant flaws & evidence supports that they only recovered a small portion of the diamonds. Even so, gem diamonds >28 carats were recovered along with a octahedral diamond fragment from a larger diamond estimated at 80 to 90 carats. But much larger diamonds were very likely missed by the mills, and these deposits likely contain hundreds of thousands of carats! In Wyoming, kimberlites yielded 50% high-quality gem diamonds. In Colorado, about 30% with gem-quality.

Little effort to outline this resource has been done by the respective state geological surveys in recent years. Research expenditures on diamonds in Wyoming, Colorado, Montana & Kansas has been nearly non-existent compared to the tens of millions of dollars spent for Canadian research along with the hundreds of millions in exploration by companies. Canada now has some commercial diamond mines developed since 1998 an others in the planning stages. In fact, state and federal agencies in the US, which should be conducting research, have only hindered research.

Past work has shown that nearly 50% of the diamonds in this craton have been very high quality gemstones. But at the pace that various government agencies are investing to outline this resource (currently non-existent) is shameful and little will happen until a major diamond is accidentally found by a prospector or rock hound.





Diamonds from the State Line of Colorado & Wyoming



In Canada, it typically takes $1.5 million per discovery (whether diamondiferous or barren). The Wyoming Geological Survey invested <$20K in research over the past 30 years! - "It is no wonder why nothing is happening in this region, yet a new multi-$billion dollar industry potentially awaits discovery".

And the author believes he has found enough kimberlites, anomalies and colored gemstone deposits in this region that could have enough value to pay for a significant portion of the national debt (prior to Obama). In addition to significant diamond resources, two world-class colored gemstone deposits were discovered along with other major and significant gem deposits. The area not only provides some of the better samples of kimberlite, but has also been the most productive in the US as far as the number of diamonds recovered.

KIMBERLITE PIPES
Hundreds of kimberlite pipes occur in a large group of 12 districts within a major diamond province in Colorado and Wyoming. Some of the recently discovered districts enclosed as many as 50 known cryptovolcanic structures (along with potentially dozens of hidden kimberlites).

Aerial photos showing (left) - one of more than a dozen distinct cryptovolcanic structures (depression filled with rounded boulders & cobbles containing calcium-carbonate-rich soils within a granitic terrain) in the Happy Jack area west of Cheyenne.

And (right) aerial photo of one of the largest cryptovolcanic structures in North America at the Twin Lakes field south of Interstate 80 west of Cheyenne. This field of >50 such structures (kimberlites?) are outline by distinct vegetation anomalies, depressions in silicate-rich Proterozoic age granites & gneisses in cratonized belts, have considerable calcium-carbonate salts (white bull's eyes), rounded boulders, are structurally controlled and located between the State Line and Iron Mountain diamondiferous kimberlite districts.

The author discovered these in the State Line district, the Red Feather Lakes district, the Boulder district, the Happy Jack district, Horse Creek district, Iron Mountain district, Middle Sybille Creek district, Indian Guide district, Harrison district, Twin Mountain district, Eagle Rock district, King Rock district, Strong Creek district, Grant Creek anomaly, Lone Pine field, Lost Lake field, Creedmore Lake field, Chicken Park field, BG field, Lake Owen district, and the Douglas Creek district. Very few of these are tested but provide evidence for one of the largest kimberlite provinces in the world. IN the past, the author mapped the two largest diamondiferous kimberlite districts in the US (Iron Mountain and State Line) in this region.

LAMPROITE AND LAMPROPHYRE
One of the largest lamproite fields in the world (Leucite Hills) and one of the largest lamprophyre fields in North America (Missouri Breaks) occurs in this region, and few of these have been tested even though a group of lamprophyres near Cedar Mountain Wyoming contain diamonds and several lamprophyres have produced diamond-stability minerals, and evidence suggests that one of the largest lamprophyre fields in the world is located in southwestern Wyoming near the Leucite Hills lamproite field.

PLACER DIAMONDS
Placer diamonds are likely to be found all over the region, but little exploration has occurred. In the state line district, the kimberlites are deeply eroded providing geological evidence for a very large placer diamond population to occur in the adjacent draininges. To date, only a few samples have been taken in these drainages, yet placer diamonds as large as 6.2 carats were recovered in the past.


IOLITE
One deposit discovered more than 10 years ago yielded the largest iolite gemstone in the world at the time of the discovery - a >1700 carat iolite. Recently, a world-class iolite deposit was discovered where a >24,000 carat iolite gemstone was collected, but masses of gem were identified in outcrop that are estimated to weigh >a million carats. At another deposit, high-quality iolites were verified, where past exploration accidentally identified a deposit that could be the largest ever found - it is suggested that this latter deposit could host more than a trillion carats of iolite (iolite sells for $15 to $150/carat).

Many other gemstone deposits are suspected in this region. For example, nearly a dozen ruby deposits were found by searching favorable geological regions and recovering rubies in stream sediment samples while searching for diamond deposits. Need more information on diamonds, other gemstones and how to find them? We are putting together a newsletter to send out to interested prospectors and geologists - write to us at: diamondprospector@live.com.


Photo of outcrop of iolite in central Laramie Mountains.

And, I've always wanted to see if I could cleave a large diamond with my hand. So, do you have a giant diamond you would like to donate to this research project? Diamond verses Karate.
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Diamond Books by the author