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Posts Tagged ‘uranium’

Walden students in Moab

Walden students at the Arches National Park visitor center

Between third and fourth terms, Walden School holds a two-week Intersession that includes high interest classes (such as the CSI class I reported on last post) and often also includes a field trip. This year we traveled to Moab, Utah which is the gateway for some of the most incredible scenery, geology, and adventure activities you can find anywhere. The town is situated in a valley between two national parks (Arches and Canyonlands), a mountain range (the La Sals), and next to the Colorado River.

Moab is the last place on the river that is easily accessible for putting boats in and out until you get all the way down to Lake Powell and Bullfrog Marina. If you want boating, kayaking, bicycling, hiking, slick rock four-wheeling, camping, or just photo opps, this is the place. It’s also an interesting place for unearthing the elements.

Charlie Steen

Charlie Steen in 1961

Moab was a sleepy town in the early 1950s when an unlikely discovery changed everything. Charlie Steen was a geologist and prospector who had heard that uranium was a byproduct of the vanadium mines scattered around the American southwest. The Atomic Energy Commission needed domestic sources of uranium and set an artificially high price for it as an incentive for prospectors and miners to discovery new sources, and Steen headed to Utah to seek his fortune.

Steen had a theory that uranium might accumulate in an anticlinal structure just as oil does, and the area around Moab consists of underground salt domes deposited about 350 million years ago when a mountain range known as the Uncompaghre Uplift covered what is now the border between Utah and Colorado. A large syncline called the Paradox Basin formed just west of this mountain range, and during the Pennsylvanian and Permian periods it was filled with a shallow ocean. This sea frequently dried up, leaving huge layers of salt, which were eventually covered with sand dunes (now the Navajo and Entrada sandstones) and the Mancos shale layer during the Mesozoic Era. The weight of these overlying layers caused the salt layers to shift and bulge in places and form depressions in others. The Moab Valley is one of these depressions, and Arches National Park is one of the domed up areas. As the salt bulged up, it cracked the sandstone layers into a series of parallel cracks. Water got into the cracks and created fins, or thin ridges which eventually eroded further into the arches that the area is famous for. But underneath it all lies the salt. Steen felt that any uranium that eroded off of the ancient Uncompaghre Mountains would accumulate in the Paradox Basin and be deposited in the sandstone found there, now pushed up into an anticline.

Rock fins

Eroded remnants of rock fins in Entrada Sandstone at Arches National Park

Everyone else thought this theory was ridiculous. Uranium in sandstone? Impossible! Steen spent two years prospecting through the area living in a tarpaper shack, feeding his family on poached venison. He didn’t even have enough money to buy a Geiger counter to check samples for radioactivity. Then, in 1952, he struck a deposit of high-grade pitchblende ore in the Lisbon Valley southeast of Moab and named it the Mi Vida (“My Life”) mine. Suddenly rich, he invested in various other mines and uranium mills, built a large house on the edge of the cliff overlooking Moab, and made sizable donations to build the local hospital and to improve the airport, and even flew in a private plane to Salt Lake City once a week for dance lessons.

Mining Districts of Utah

Mining Districts of Utah. Uranium/Vanadium deposits are shown in green.

Steen’s success started a uranium boom in southeast Utah, and other deposits were soon discovered. They were mostly located in three major areas (as shown by this map of Utah’s mining districts – the green areas are uranium/vanadium mines). The first area centered around Moab and the Paradox Basin. A second major area was around the edges of the San Rafael Swell. The third was along White Wash, a remote area east of present-day Lake Powell. Uranium processing mills were built at Moab and Monticello, and the area prospered as money and jobs poured in.

By the mid-1960s the U. S. Government decided it had enough uranium stockpiled and stopped purchasing it. The price fell, and the boom days were over. Unfortunately, radiation from the tailings piles at the mills had so contaminated the two towns that the incidence of cancer is greatly increased compared to similar populations elsewhere. Both tailings piles are being removed and reprocessed to make them safe.

Double Arch

Double Arch at the Windows Section, Arches National Park

For our trip to Moab, we stayed in small cabins at an RV park at the north end of town. The weather, being March, was windy with a storm front moving in slowly from the northwest as we left Provo, but traveling east we got ahead of the storm and found the weather nice when we arrived around noon on Wednesday. The group split into two parties, one going to the Fiery Furnace in Arches NP and the rest going to the Windows Section (my favorite area). I took some photos and video of Double Arch, Balanced Rock, the La Sal Mountains, and other areas between the Park entrance and Windows Section.

The La Sal Mountains

The La Sal Mountains and Windows Section, Arches National Park

On Thursday, most of the group hiked in to Delicate Arch. The weather had turned colder and more threatening as the front slowly approached, but it was a nice hike to the arch (about 1.5 miles). Along the way, at the backside of the first hill, is an unusual rock formation of purplish chert. It was formed from the same red sandstone all around us, but here there was a fault line caused by the buckling of the underlying salt domes. As the two sides of the fault moved against each other,  contact metamorphism converted the sandstone to chert, the red iron oxide turning purplish as it often does when metamorphosed.

Delicate Arch

Delicate Arch in Arches National Park, Utah

Chert boulder on trail to Delicate Arch

Chert boulder on the trail to Delicate Arch

After Delicate Arch we hiking into Landscape Arch, then returned to camp as the day turned colder. We ate dinner in Moab as a faculty at a decent pizza place as it finally started to rain, and enjoyed the hot tub that evening. On Friday we packed up and headed back to Provo.  I was able to get some great photos of the geologic features of Arches National Park.

Landscape Arch

Landscape Arch in Arches National Park

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Reid Nixon

S. Reed Nixon, nuclear engineer

On Nov. 30, I had the privilege of interviewing S. Reed Nixon, who lives not far from where I do in Orem, Utah. I met him through my wife, who has known the Nixons for several years. Over the summer, we went to visit them and Reed told me of some of his experiences as a nuclear engineer on Admiral Hyman Rickover’s staff during the 1950s. I couldn’t pass up such an opportunity, so I arranged to bring over my video equipment and interview him on camera.

Reed got into nuclear engineering by chance. He started out by receiving a B.S. in electrical engineering from Caltech in Pasadena (where he had Linus Pauling as a chemistry professor – according to Reed, Dr. Pauling would nervously pace up and down the chemistry lab during his lectures, turning the Bunsen burner gas stopcocks on and off). This was in the late 1940s, after Reed had served two years in the Navy. At the time, Robert Millikan was Chancellor and would have the seniors and their parents over for tea each year. He told how gracious Dr. Millikan was to his mother at the tea party.

Upon graduation, he moved to Provo, Utah where he taught math part-time at Brigham Young University and then started working for Telluride Power Company, which ran the power utilities for southern Utah at that time before it was bought out by Utah Power and Light. Telluride Power Company originated in Telluride, Colorado when the mines there began to have trouble with ground water. The Nunn brothers bought out a number of mines, then contracted with George Westinghouse to design a hydroelectric power system based on alternating current as conceived by Nikola Tesla. This was the world’s first commercial AC system, which supplied power to the mines for pumps that kept the water at bay. Reed had some interesting stories about this original power system, including how it was difficult and dangerous to shut off. When the mines in the Tintic Mining District around Eureka, Utah began to have the same trouble with flooding, the Nunns built a hydroelectric plant in Provo Canyon (now the site of Nunn Park) and transmitted electricity about 40 miles across the valley to Eureka.

USS Nautilus

USS Nautilus, SSN 571

After a few years with Telluride Power, Reed heard of a new laboratory being built in Arco, Idaho to process spent nuclear reactor fuel rods. They needed an electrical engineer. This was about 1951, and nuclear reactors for generating power were a brand new invention. As Uranium-235 splits, it releases free neutrons, which in turn split other atoms. The fission byproducts, such as Barium-141 and Krypton-92 (among other isotopes), are themselves mostly radioactive. Some byproducts, however, are not, and they act as neutron sponges, so that of the three neutrons given off by a single U-235 atom, only about 2.5 are available to continue the reaction. Eventually these products poison the reaction, to where fission will no longer occur spontaneously. The Arco facility (now the Idaho National Laboratory) was built to take the “poisoned” fuel rods and remove the impurities, so that the remaining U-235 could be re-used in reactors. It also was the training facility for the prototype reactor for the USS Nautilus.

After a year or two at INL, Reed applied to receive training in nuclear engineering at Oak Ridge National Laboratory, which was the primary source of U-235 enrichment at the time. It was such a new field that only one textbook had been written, and he could see an opportunity to get in on the ground floor of a whole new technology. Hyman Rickover (later an Admiral) had recently been put in charge of developing nuclear reactors for the navy, and was sending his people to Oak Ridge as well. While there, Reed got to know the navy personnel and also finished as one of the top engineers in his class. His job at INL had meanwhile been eliminated, so he decided to take a chance and apply to be on Rickover’s staff.

Hyman Rickover

Admiral Hyman Rickover, father of the nuclear navy

Rickover was infamous for being a hard-driven workaholic. He was also abusive, profane, and intolerant of anything less than perfection in his subordinates and in the contractors (such as General Dynamics) who were building the first nuclear submarines. He personally selected his staff members and all officers in nuclear vessels until his retirement in 1983. His recruiting interviews were legendary; he was known for being so confrontational during the interviews that several candidates tried to attack him physically, and so he usually had his director of personnel in the room as well for protection. He would push a candidate to the edge – he already knew their technical qualifications or they wouldn’t have been there in the first place. What Rickover wanted to know is how much abuse the person could take.

USS Nautilus

USS Nautilus, SSN 571

Reed Nixon’s interview was probably the easiest one that Rickover ever gave. After Reed was accepted, his job was to act as a liaison with the contractors as they built the USS Nautilus (SSN 571) and USS Seawolf (SSN 575), making sure that all the specifications were followed exactly, even down to inspecting each weld on the reactor vessels with X-rays. Rickover was a demon for quality assurance, and would insist that contractors tear a system apart and start over if there was even the slightest flaw. Reed was a part of Rickover’s staff through the launch of both vessels.

Using nuclear reactors to power naval vessels has many advantages, especially for aircraft carriers and submarines. The power plant can operate for many years without refueling, so there is no need for tankers to follow along and act as targets for enemy torpedoes. Also, the old diesel subs during World War II were noisy and fairly easy to locate, since they had to run close to the surface in order to pull in air and discharge exhaust from the diesel motors. Nuclear reactors run quietly (no moving parts except the propellers) and have no exhaust, so they can run silent and run deep. Our “boomer” subs (those with nuclear weapons) are said to “hide with pride.” Nuclear carriers, such as the USS Enterprise (“nuclear wessels” anyone?) and the USS Nimitz, employ at least four separate reactors. They don’t need to take up a major portion of the ship with diesel tanks, so they can hold more planes and ordnance.

The Nautilus was the world’s first nuclear powered vessel, which used what is now a standard design of saturated water cooling. It was launched in 1954, and was used to test the feasibility of nuclear reactors on ocean vessels. Two of its first accomplishments were to sail under the North Pole (Operation Sunshine) and to sail all the way around the world underwater, thereby living up to its namesake by going more than 20,000 leagues under the sea. It was decommissioned in 1980 and is now a museum in Groton, Connecticut.

USS Seawolf

USS Seawolf, SSN 575

The Seawolf used a more advanced superheated water system with liquid sodium metal as the primary coolant. The sodium, however, was corrosive and difficult to maintain and the pre-heaters for the superheated steam rarely operated at top output. The Seawolf was known as the “Blue Haze” because of a sodium leak that occurred during the original reactor fitting. It was eventually refitted for a standard reactor in 1959. The liquid sodium reactor was sealed in a steal container and towed out to sea on a barge, then sunk 120 miles east of Maryland. The Navy has not been able to relocate the container. Originally launched in 1955, the Seawolf stayed in service until it was decommissioned in 1987 after a long and distinguished career.

Admiral Rickover’s insistence on perfect quality has led to our nuclear navy now having over 5400 reactor years and over 200 million miles sailed without a single accident or even a safety incident related to the nuclear reactors. This perfect operational record should convince the general public just how safe and reliable nuclear power can be, but unfortunately it’s a fact that often goes overlooked.

Reed Nixon worked in Rickover’s office for about two years. One memory he shared of his time there was a memo that Reed wrote to a contractor in which he said that, “we desire that you do the following . . . .“ Rickover wrote a caustic correction in the margin of the memo saying, “We’re the Navy! We don’t desire anything! We demand it!” Reed eventually left Rickover’s staff to work in the private sector as a consultant, promoting the use of nuclear power in industry. Rickover wasn’t at all happy for him to leave.

The Nixons

The Nixons

Our interview ranged over many subjects, from Nikola Tesla to nuclear reactions and the disposal of nuclear waste, such as the radioactive byproducts that had been removed from fuel rods at INL. Reed Nixon was very generous with his time, and it was a pleasure to hear these stories of the dawn of the nuclear age.

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by Eli West

Guest Host

Thorium reactor

Liquid Thorium Reactor

The word “nuclear” means a lot to us today. When we hear it we think of many things: bombs, reactors, uranium, “nuculur,” and radioactive; all of these are connotations of the word nuclear. Let’s explain what each of them means.

We’ll begin with bombs. The common link between nuclear and bombs, is obviously, nuclear bombs; otherwise known as atom bombs. In essence, you have a collection of uranium atoms; specifically Uranium-235, which is very fissile.  In a bomb, a lone neutron is shot at a uranium-235 atom to create uranium-236. Since uranium-236 is too unstable, the isotope breaks apart very violently, shooting neutrons everywhere, and these reactionary neutrons in turn smash into other uranium-235 atoms, and those atoms break apart and smash OTHER atoms. Which is what makes atomic bombs so explosive.

Another think we link to nuclear is uranium. Uranium is a very heavy atom. With a standard atomic weight of 238.03 g/mole, it’s on the heavy side. However, you’re probably used to hearing terms like uranium-238 or uranium-235. What do the numbers mean? Why are they different? What does it change? The number with uranium is indicating the isotope number, which simply means that there are more or less neutrons with the same number of protons. The 238 number gives you the atomic weight of the atom. In order to find out how many neutrons there are, you simply take the atomic number (which is 92, the number of protons in all uranium atoms, regardless of isotope), then take the atomic weight minus the atomic number to find the number of neutrons. In this case it is 238-92=146. So we know that there are 146 neutrons in each atom of uranium 238. Compared to hydrogen, that’s heavy.

Nuculur. I’m not even going to go into that, except to say that the correct pronunciation, by the way, is “new-clear.”

Radioactivity: it’s a word with a history. It’s a word that’s gotten a pretty bad rep over the years, through romanticizing, myths, and fiction. Everyone has heard the stories of people getting hit with gamma radiation and gaining super powers! Or of radiation being like the Black Death, destroying any who get near. The truth is, EVERYTHING is radioactive. Now don’t get scared! That term isn’t quite as bad as believed! Let’s get a few things straight, what exactly does, radiation mean? Well, everything radiates. EVERYTHING. Radiation is just the constant output of energy. We radiate heat, and light, just like the sun; food radiates heat! Some things just radiate such high-energy waves that they become dangerous. THAT is radioactivity.

“Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability.”

http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.html

Thorium in USA

Thorium concentrations in the USA

Now, where I am going with all this is thorium. What is thorium? It’s an incredibly heavy atom, much like uranium. It has large isotopes, much like uranium. Both of them have a huge half-life, and are highly radioactive; the differences between them are: (1) uranium, when used in nuclear reactors, produces a new isotope of uranium, which can be weaponized in the form of depleted uranium. It can be formed into what are essentially large bullets crafted out of the depleted uranium isotope. The bullet is incredibly dense, and when shot at high enough velocities, can pierce tank armor. It doesn’t explode in a nuclear bomb, but it does spray radioactive uranium all over the inside of the target tank. Thorium, on the other hand, when used in a nuclear reaction will not produce a weaponizable material. Thorium and uranium are both naturally occurring materials.

Thorium is abundant compared to uranium. So as a fuel source it would be cheaper, MUCH cheaper. Thorium is not fissile itself, which means it cannot sustain a low energy chain nuclear reaction, which means that it is not actually usable in nuclear reactors by itself. However, it is fertile, which means slow neutrons can be added to it to change it into U-233 (or uranium-233), which is fissile. That’s why we can’t just start mining thorium and tossing it in nuclear reactors all over the world. First we need to create reactors that can change it into U-233, which would then be fissile.

Thorium deposits in Alaska

Thorium deposits in Alaska

The word thorium has a very simple background. The man who discovered thorium simply decided that Thor was a pretty cool guy, and that maybe he should call this thing thorium!

As of right now there are a few companies around the world that are developing thorium reactors. Their projections for finishing the project are around 2015. That’s five years. Not to mention the actual two or three years it would take to build each reactor. So, the technology is coming, but is a ways off. Some believe that once they get the reactors running, that we could wean the world off oil in as little as five years, or by 2020. However, that’s probably a bit optimistic, and there still is a lot of work before we reach that point.

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Calderas of Juab County

Volcanic Calderas of Millard and Juab Counties, Utah

Usually, when one thinks of rocks and geology it’s all a bit impersonal; after all, they were formed in the distant past, in many cases hundreds of millions of years ago. Most of the rocks in western Utah, where I’m from, were laid down as ocean deposits during the Paleozoic Era. Now all the layers of shale, limestone, and dolomite have been thrusted, twisted, and even overturned, so that in some areas the Paleozoic rocks lie on top of younger Mesozoic rocks. How could this have happened? But in addition to these sedimentary rocks, there are some anomalies; whole mountains that puzzled me because they didn’t fit in. My grandfather, who lived next door to us in our small hometown of Deseret, would take me for drives out on the west desert looking for trilobites or pine nuts or just collecting rocks. One area we visited was Topaz Mountain at the southern end of the Thomas Range in Juab County, where one can find topazes just by walking along an arroyo on a sunny day, following the flashes of light. The rocks there are weird, with strange cavities and a light gray texture much different than the surrounding mountains. I wondered where it came from, how the topazes got there, how old the rocks were, and above all, how geologists were able to answer these questions.

Desert Mt. Pass

View from Desert Mt. Pass

This was all very interesting to me as a child, but then geology got personal. My father was a farmer and cattle rancher, and one day in June of 1971, we were hauling a load of yearling heifers out to our ranch in southern Tooele County (about 50 miles due north of Deseret). As we were driving our old 1952 model half-ton truck over the pass on Desert Mt., the brakes and clutch both failed at the same time and we found ourselves rolling down the steep and winding road without any means of stopping (the road has since been improved, as you can see at right. Back then the road cut along the left side of the pass and was much more dangerous). Dad tried to slow the truck down by ramming it into the embankment on his side, but the impact jarred the cab, flung open the door on my side, and threw me from the cab (this truck had no seat belts). Fortunately, there is a gap in my memory at that point for several seconds. The next thing I can remember is lying on my back looking at the truck as it rolled away from me and disappeared out of sight over the edge of the embankment. Then I saw my right leg, which was twisted unnaturally, with my thigh badly torn up – a whole piece of my thigh seemed to be missing, as far as I could see through the tattered remains of my pants. The best I can figure is that the rear dual tires of the truck rolled over my leg, breaking it in two places and tearing up the skin and underlying tissue badly. Or my leg dragged over the rough, sharp rhyolite rocks of the mountain. Or both.

Desert Mt. Rhyolite

Rhyolite formations at Desert Mt. Pass

This was a hot day in June. We had water and snacks, but my father had sprained his ankle and could not walk. This was before cell phones or even CB radios, and we had no way of getting help. You have to visit the west desert of Utah to appreciate just how isolated it is. Dad lit the truck on fire, hoping the column of smoke would attract attention from the ranchers (including my grandfather) across Ereksen Valley, but no one saw it. Hours dragged by. I was slowly bleeding to death as blood seeped out of my wound, and I was going into shock. After about five desperate hours, my father saw a car sitting on the road leading up to the pass; they had stopped when they came around the corner and saw the smoldering remains of our cattle truck. Dad stood up and waved, and they drove on up. The car was driven by a an elderly couple from Odgen, Utah: rockhounds who were out on the west desert looking for Topaz Mt. All they had was a hand-drawn, inaccurate map and they were off course by 40 miles. Dad was able to ride in to the nearest phone (about 15 miles) and call the ambulance and Doc Lyman from Delta. After several days in Intensive Care, two months in the hospital with skin grafts, and another three months in body casts, I was finally able to walk again. I am lucky to have two legs.

So my life was profoundly affected by the geology of Utah’s west desert. Desert Mt. almost killed me; Topaz Mt. saved my life. So I have understandably been curious about the geology of these two mountains. I can honestly say that I am a part of that geology – somewhere on Desert Mt. there’s a small patch of dirt that used to be me. And that geology is a part of me, too – the doctors were never able to get all of the small rock fragments out of my leg that had been ground in. Yes, I know it’s a bit grotesque, but it’s literally true.

That’s why I’ve wanted to complete these episodes on the beryllium deposits of western Utah before doing any others, because telling that story includes the story of the geology of the area and how those two unusual mountains came to be there in the first place. The episodes are coming along nicely, and I have completed the geology section completely and offer it now for your enjoyment. The first episode (on the sources, uses, and geology of beryllium) will be ready in a few days; the second episode on the mining, refining, and hazards of beryllium will be ready by next week.

Here is the script of this section, in case you’d like to read along with the video:

Geologic Origins of the Bertrandite Deposits in Western Utah

To understand the origins of the beryllium deposits in the Spor Mts. we have to go back to when western Utah was still under the ocean. For hundreds of millions of years, this ocean floor built up gradual layers of shale, limestone, and dolomite. The North American tectonic plate began to separate from the rest of Pangaea about 200 million years ago and was moving westward into the Farallon Plate, which was subducting under the western margin of North America. The sediments carried down with it were heated and rose toward the surface to cool as the granitic plutons of the Sierra Nevada Mts. For the first time, the western half of Utah and Nevada rose above the ocean.

Overhead View of Topaz Mt. Area

Aerial View of Topaz Mountain Area

Then, about 150 million years ago, the North American Plate sped up; instead of moving about 2.5 cm per year, it leaped ahead at the breakneck speed of about 8 cm per year. Instead of subducting, the remnants of the Farallon Plate were pushed under western North America, scraping and dragging the roots of the continent with it. This friction caused a wave of thrust faulting and mountain building to travel west to east across Nevada (the Nevadan Orogeny), then across western Utah (the Sevier Orogeny) about 125-75 million years ago. A huge mountain range rivaling today’s Rockies sat on the Utah-Nevada border, with sediments washing off of it into an inland sea to the east to form the upper layers of the Colorado Plateau as dinosaurs wandered through the mud flats and swamps. These swamps became the coal deposits of central and eastern Utah.

As the thrust faulting continued east, it encountered the thick Colorado Plateau and bent it into the huge anticline of the San Rafael Swell. When it reached Colorado and Wyoming about 55-60 million years ago, the thrust faulting created the Laramide Orogeny that resulted in the Rocky Mountains, including the Uinta Mountains of northeast Utah.

About 50 million years ago the North American Plate slowed down again and the remnants of the Farallon Plate collapsed from underneath, pealing away in a wave that now traveled from east to west. A wave of volcanism traveled with it, moving back across Utah and Nevada. Much of the mineralization found in Colorado, Utah, and Nevada occurred at this time, including the silver, copper, zinc, lead, and beryllium deposits of Utah. In western Utah, the volcanism produced several zones of Andesitic volcanoes with calderas and ash flows, including the Thomas-Drum Mt. caldera along with calderas at Keg Mt. and Desert Mt., about 45-39 million years ago and continued for at least 30 million years through several phases. In the first phase, quartz-rich magmas formed the calderas and ash flows that covered much of the area and produced the gold, copper, and manganese deposits of the Detroit District in the Drum Mts. The second phase of area volcanism occurred as the calderas in the Spor and Drum Mountains subsided and were filled with rhyolite from the Dugway Valley caldera about 38-32 million years ago.

Utah during Oligocene Epoch

Utah During Oligocene Epoch, 30-40 million years ago

The ancient thrust faults and collapsed calderas created fractures, which served as avenues to intrude veins of mineral-bearing magmas. Beginning about 25 million years ago, a third phase of volcanism pushed domes of highly alkaline rhyolite rich in fluorine and beryllium up through these fractures. The fluorine and beryllium minerals formed gases that were injected into the thrust faults and eventually encountered ground water, which flashed into steam, shattering the surrounding rhyolite and forcing the beryllium minerals to precipitate throughout the fractures and empty spaces in the host rhyolite rocks. Gradually, minerals were deposited as crystals of topaz, fluorspar, garnet, and bertrandite in the Thomas-Spor Ranges, and red beryl in the Wah Wah Mts. Additional trace elements such as uranium, lithium, aluminum, zirconium, iron, and thorium were also deposited.

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