Jargon

Today I take my text from Charles B. Hunt, US Geological Survey geologist mapping the Henry Mountains in southern Utah in the 1950s.

"A cactolith is a quasihorizontal chonolith composed of anastomosing ductoliths whose distal ends curl like a harpolith, thin like a sphenolith, or bulge discordantly like an akmolith or ethmolith."

In the 1950s US Geological Survey publications were intensively reviewed for style and accuracy, so it’s a minor miracle that the definition got published. This was Hunt’s way of poking fun at the proliferation of –lith words for various rock bodies (the suffix derives from Greek lithos, stone). The definition has a cult following among geologists – I love to roll it off my tongue at parties, where people then stare at me with more than the usual concerned look – so much so that when it was removed from the Glossary of Geology, the hue and cry was such that it returned to future editions, where it remains to this day.

All scientists, all specialists, have their own argot, jargon, and particular terminology that tends to exclude the uninitiated from their secret club. At this stage in my career, one important motivation for me to write What Things Are Made Of is to try to open those secret doors to give non-scientists a look at geoscience. Whether I succeed or not can be argued, but I am trying. Will I be the next Simon Winchester (The Map that Changed the World, Krakatoa) or John McPhee (Annals of the Former World)? I’d be the last to compare myself to them, but they give me a clear target for lucid writing to which I aspire.

Fragments of the starry firmament

Early residents of Afghanistan mined the rock lapis lazuli more than 6,000 years ago for jewelry, including the famous gold mask of Tutankhamen. By the 6th Century AD they began to produce the deep blue pigment now known as ultramarine. They used it in cave paintings; its use spread to China and India, and eventually to Europe by about 1100 AD.

Grinding the blue rock, mixing it with waxes and oils, and processing in a lye solution yielded natural ultramarine pigment.

Lapis lazuli’s rarity made for notable expense (greater than gold) in making ultramarine pigment. In European monasteries, highest quality ultramarine was used only on the most important, prestigious artworks, for the robes of Mary and the Christ child. By the 1820s, a synthetic version was devised, and reliance on Afghan sources, the most significant in the world, waned.

The rock lapis lazuli contains multiple minerals, with the blue color coming mostly from two complex sodium-calcium aluminosilicates, lazurite and sodalite.

Even after synthetic dyes became the rage in the 1850s and 1860s, the natural material still served special purposes such as printing postage stamps. Stamp collectors who own blue-tinted U.S. postage stamps from the 1860s (such as the 3¢ ultramarine locomotive in the 1869 pictorial issue) probably have some microscopic bits of Afghan lapis lazuli.

The word ultramarine means “beyond the sea,” whence came lapis to Europe. Pliny the Elder gave the beautiful stone a more admiring description, calling it “a fragment of the starry firmament.”

Photo of polished slab of lapis lazuli, from Wikipedia under the Creative Commons Attribution ShareAlike 3.0 License

More about neodymium

One of the most common search words used by people who end up here is neodymium, the rare-earth element critical to powerful magnets in applications such as electric cars, wind turbines, and MRI machines. So I decided to write a bit more about rare earths and their worldwide occurrence.

Although rare earths are actually moderately common in the earth's crust, economic concentrations are indeed quire rare.

The Bayan Obo deposit in northern China, about 100 km from the Mongolian border, is presently the most productive mine complex for all rare earths. China produces 97% of the world's rare earths. Two North American deposits have recently attracted attention, because Americans are increasingly aware of our use and dependency on China for these elements (averaging 91% of U.S. imports), and because the price for some of the 17 rare earths is approaching levels to make mining them here economic once again.

The mine at Mountain Pass, in California’s Mojave Desert, was the largest rare-earth producer in the world until the 1990s when China took over. Molycorp, owner of the deposit there, has been processing accumulated ores for a couple years, although the mine itself has not reopened. And for final processing, they must ship their product to—you guessed it—China, the site of the only separation plant. Constructing one in the U.S. would be a huge investment, one nobody is presently willing to undertake.

Another promising undeveloped rare-earth deposit lies along and adjacent to the Continental Divide between Montana and Idaho, centered on the Lemhi Pass area. Two sites are held by U.S. Rare Earths, Inc., a private company.

The Idaho deposits were discovered and initially investigated in the late 1940s and 1950s because they held radioactive thorium, important in nuclear weapons development. The geologic setting is complex: igneous (formerly molten) rock bodies that were once thought to be part of the Idaho Batholith (around 100 million years ago, but with a wide range of dates) are now considered to be Mesoproterozoic (something like 1300 million years ago) in age, and to have metamorphosed (changed by heat and pressure) the surrounding rocks of somewhat older age. Sedimentary rocks of the Gunsight and Apple Creek Formations became quartzites and gneisses thanks to that metamorphic cooking. They also became the host rocks for the veins containing rare earths, gold, and other minerals.

The whole area is complicated further by thrusting – faulting, breaking rocks, by pushing older layers up and over younger layers, sometimes on scales of tens of kilometers or more, something that probably happened over tens of millions of years around 60-70 million years ago. Then, about 40 or 50 million years ago, Nature put a pile of volcanic rocks on top of the whole mess.

With all that going on, you can imagine that geologists are still working out the details, and what I write above is just a broad-brush overview. Some of the basic geologic mapping by U.S. Geological Survey, Idaho Geological Survey, and other scientists was published only a few years ago. It is not completely clear (at least not to me) when the valuable minerals came in—some indications say it was associated with the early metamorphic cooking, some suggest later. But the high grade of the ore at Lemhi Pass and near Salmon, Idaho, is clear, making the two sites perhaps the highest potential in the U.S. as undeveloped rare-earth resources.

Exploration and economic evaluation is underway for two other isolated rare-earth deposits, one near Sundance, Wyoming, and one beneath 600 feet of rock in southeastern Nebraska. Another potentially important North American rare-earth deposit is being investigated at Thor Lake, north of Yellowknife, Northwest Territories, Canada. We’ll save these possibilities for another post.

Mineral riches: why here and not there?

My historical tours in Butte always include geological background, including what, where, who, when, how, and how much. Among the most frequent questions from visitors is why—why did Butte (or any other big mining district) end up with so much copper and silver in a tight, 5-square-mile zone, and otherwise similar areas just a few miles away did not?

My answer always is, “If I knew that, I could win the Nobel Prize in Economic Geology.” Not that there is such a prize, but you get the idea. Geologists understand mineral deposits pretty thoroughly, up, down, sideways, and through time. But that ultimate question of “Why?” typically remains unclear.

The easy cop-out answer is something like, “Well, more copper (or whatever) than usual was scattered in the rocks, and when magmas rose (or some other kind of geologic event happened) the metals were mobilized and concentrated into veins because there were more fractures (or some other rock feature that focused the mineralizing fluids).”

That’s fine, but it’s almost entirely “how,” not “why.”

Why was there more tourmaline in western Turkey to put boron in hot water there, making Turkey the world leader in boron production? Why did a 45-million-year-old lake in southwestern Wyoming end up with enough highly concentrated sodium carbonate (a compound critical in glass making) to make that deposit the largest in the world? A good answer is challenging to find.

We’re not totally clueless, of course. Researchers study primary mechanisms like black smokers on the sea floor, possible fundamental sources of deep-earth elements like copper, lead, and zinc. Such processes may represent the earth’s first version of mineral concentration. Later events, reasonably well understood, may take those primordial deposits and convert them into exploitable economic deposits in the earth’s crust, near enough to the surface for miners to work today.

But “Why?” can be the hardest question to answer in geology, just as it may be in human affairs.

US oil imports from Saudi Arabia decline

In recent years, Saudi Arabia has been in a near-tie with Mexico for the #2 spot as a source of US oil imports. Late last year, Saudi Arabia dropped to fifth place.

Good news, you say? Maybe. The forces moving oil around the world are complex, and in addition to recession-related decline in oil consumption in the US (mostly in diesel and jet fuel, not so much in gasoline), Saudi Arabia is shifting its market more toward China. This matters, because as exporters find markets willing to pay higher prices, those prices will increase in the United States as well, even if we are buying less. And as exporters begin to care less about the economic stability of their lower-demand customers, what the U.S. says about the question becomes increasingly irrelevant.

Believe it or not, Saudi Arabia has had a vested interest in keeping oil prices low enough to keep the economic engine of the U.S. purring. Gouging is not in their interest—contented, spending customers are. When other customers supply most of the money any exporter needs, those who are lower on the totem pole become second-rate, at least as far as price concerns go.

For the record, here are the top import sources for U.S. oil in November 2009:

• Canada – 23% of imports
• Mexico – 9.8%
• Nigeria – 8.8%
• Venezuela – 8%
• Saudi Arabia – 7.7%

The next tier of import sources vary from month to month, but each of the following nations supplies the U.S. with about 3% to 4% of our oil imports: Angola, Iraq, Algeria, and Russia.

Virtually every drop of Canadian oil exported comes to the United States. So don’t think we can simply “get more” from Canada. There is no more to give, except as Canadian supplies slowly grow. With prices as low as they are ($78 or so per barrel), the Canadian Tar Sands are barely economic, or non-economic, to produce. Which means they are not produced.

Buy American!

I love to read letters to the editor whose writers seem to believe that all our problems (or at least those of the auto industry) could be solved by Americans buying American cars.

I’m not going to get into the question of what’s an “American Car Company” – are Toyotas made in Tennessee American or Japanese? Does Daimler’s former ownership of Chrysler mean that they made foreign cars? Who owns Saab? I have no idea. I want to share some information about the sources of raw materials that make up the “American” car.

Iron to make steel – far and away the greatest proportion, by weight, of every U.S.-made car – comes from mines in Minnesota and Michigan. 240 pounds of aluminum comes from either recycling or imported ores and concentrates, because the U.S. has no domestic production of bauxite, the only ore of aluminum. Smaller in volume, other elements are nonetheless critical components of modern vehicles.

• Copper – on average, a third imported from Chile, Canada, Peru.
• Lead – probably mined in Missouri or Alaska
• Zinc – mined in the U.S., refined overseas
• Manganese – 100% imported from Gabon, South Africa, China
• Chromium – mostly imported from South Africa, Kazakhstan
• Nickel – mostly imported from Canada, Russia, Norway
• Magnesium compounds and metal – from Canada, China, Russia
• Sulfur – produced in 29 states and imported from Canada, Mexico, Venezuela
• Silicon – half imported, 60% of that from China and Russia
• Molybdenum – from U.S. mines in the Rocky Mountain States and Nevada
• Vanadium – 100% imported from Czech Republic, South Africa, China
• Platinum – 91% imported (South Africa, Germany)
• Palladium – 72% (Russia, South Africa)
• Antimony – 86% dependent (China)
• Barium – 79% import reliance, almost all from China
• Beryllium – from Utah
• Cobalt – recycling (20%) and imports (80% - Norway, Russia, China)
• Gallium – 99% dependent, from China, Ukraine, Germany
• Gold – U.S. is a net exporter. Nevada is the leading producing state.
• Neodymium – 100% dependent. China produces almost all in the world.
• Tin - recycling (20%) and imports (80% - Peru, Bolivia, China)
• Lithium – more than 50% imports, from Chile and Argentina
• Vinyl plastic – made from natural gas (19% imported, mostly from Canada) and salt (17% imported, largely from Canada and Chile)

There’s more, but that’ll do for this post. Are you saying, “I really don’t care whether my car has neodymium and lithium or not.”? You should. As gasoline prices increase, those and other elements will become dramatically more important in electric batteries and in improving fuel efficiency. Do you like your car’s glossy paint? Barium from China contributes to that sheen. Platinum and palladium make your catalytic converter work.

What Things Are Made Of covers the geology behind China’s near-monopoly in rare-earth production (including neodymium) and Bolivia’s status as the future “Saudi Arabia of lithium.”

Buick photo in public domain, via Wikipedia

Analogs

Geologists are all about analogs. Since we don’t have actual time machines, we have to look at modern situations to project into the past and determine what happened.

In a previous post I mentioned gypsum in Oklahoma, precipitating out of seawater on a hot, arid equatorial coastline 255 million years ago. A good modern analog for this is Umm Sa'id Sabkha, on the east coast of Qatar along the Persian Gulf (or Arabian Gulf if you prefer), in the photo below.

A sabkha (Arabic for salt flat) is a low-lying area occasionally inundated by marine water. When the water withdraws, mineral salts precipitate as the water evaporates. Sabkas are the basis for our understanding of how many ancient deposits of evaporite minerals formed, including salt (halite), gypsum (used in wallboard), and sylvite (a source of potash for fertilizer, mined in New Mexico and imported from Canada and Belarus).

Another analog: We’ve only known about black smokers (photo, left) since 1977. These hydrothermal vents on the abyssal sea floor spew superheated, metal-rich water into the ocean. Metal sulfides precipitate around the vents and provide a possible analog for ancient copper, lead, and zinc deposits exploited on land today. Deep mantle sources may be the origin of some metal concentrations in the crust.

Lots of mineral deposits can’t be explained by direct analogs—for example, we can’t really look at the roots of a modern volcano to observe the processes that may be concentrating ores there. But inferences from modern situations are probably the best way we have of understanding unusual mineral bodies and predicting where to find more.

“The present is the key to the past” – a concept first clearly expressed by Scottish geologist James Hutton in 1795 (but probably not in those exact words).

Images – Sabkha NASA, black smoker NOAA

Who’s got the oil in the US?

Perhaps it’ll surprise you to learn that thirty-one states have at least a little oil production. That leaves 19 with none at all. In most states with no oil production, there’s also little or no oil potential, just because the rocks there lack the properties for generating and trapping oil.

From the list below of non-producing states, those with some potential include most of the southern Atlantic seaboard – Georgia, South Carolina, and North Carolina. Oil accumulations may exist in sedimentary troughs in those states, as well as offshore, but exploration to date is not encouraging, so we’d call the potential pretty low there.

Volcanic rocks cover much of Washington and Oregon. That doesn’t make oil pools impossible, but the likelihood declines greatly. Most of Minnesota and Wisconsin are underlain by ancient rocks, a billion years and more old, from a time when life was limited mostly to single-celled organisms. You need teeming life to make petroleum, and even though much oil derives from single-celled life like algae, the amount of life a billion years ago was not enough to make oil – or if it did, it has not survived collisions, subductions, and other traumas the earth has thrown at the older rocks of Wisconsin. The younger rocks there are relatively thin, another factor reducing the potential for commercial oil fields. You need to bury organic material deeply to naturally cook it into oil, but not so deep as to overcook it.

So 31 states are awash in oil, getting rich on production taxes and severance taxes. Well, not quite. Almost 80% of US oil production comes from just four states. For November 2009 (data from World Oil), the four leading states in descending order were Louisiana, Texas, Alaska, and California. The other 27 producing states together account for just over 22% of total US oil.

Here’s the list of 19 states with no oil production at all in November 2009:

Connecticut, Delaware, Georgia, Hawaii, Idaho, Iowa, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, North Carolina, Oregon, Rhode Island, South Carolina, Vermont, Washington, and Wisconsin.

The map below, from the US Geological Survey, shows most of the wells in the US – more than 500,000 producing oil wells (over half the oil wells on earth), plus gas wells and dry holes. Some estimates figure three to five million wells have been drilled in the US in the search for oil and gas.

Cooking, cleaning, cooling

Fluorine is another relatively obscure element, but one virtually every American has in his or her home.

Fluorine gas derives mostly from the mineral fluorite—a beautiful mineral, prized by collectors for its multicolored cubic crystals. The Cave-in-Rock District, along the Ohio River in southern Illinois, once produced most of the world’s fluorite (also known as fluorspar). Those mines are closed now, and the U.S. is dependent on imports for 100% of the fluorspar that we consume, amounting to more than 400,000 tons each year.

Where does it go? Most fluorine goes to make hydrofluoric acid, critical in aluminum and uranium processing. And hydrofluoric acid is the feedstock for all fluorine-bearing chemicals, and this is where fluorine ends up in homes.

Teflon in non-stick cookware and Freon in air-conditioning systems are brand names for fluorinated compounds. Then there’s fluoride in toothpaste and municipal water systems, not as a communist plot but to alleviate tooth decay because fluorine in the crystal structure of calcium phosphate (the mineral making bones and teeth) is stronger than otherwise.

Enamel coating your stove almost certainly contains fluorine. Glass and steel manufacture demand it, as does cement production.

Where does the U.S. get fluorspar? Most imports (52% in recent years) come from world production leader China. Another 34% is imported from Mexico, with South Africa a distant third as a U.S. fluorspar supplier.

Photo of fluorite from Cave-in-Rock by Richard Gibson

Disclosure

This probably doesn’t apply to me, but just in case.

The Federal Trade Commission requires bloggers to disclose any freebies or promotions they get in connection with any products they discuss.

So:

No one gives me anything. Well, sometimes a friend of relative does, but I’m not endorsing them, either. I don’t get any kickbacks from the government of China for describing the Bayan Obo rare-earth deposit. Toyota isn’t breaking down my garage door to give me a Prius because I talk about the neodymium in its motor or the lithium in its battery. In case that should happen, I’ll be very happy to disclose the fact.

My goal is to be objective anyway, so if a company gave me a freebie, that wouldn’t guarantee much, anyhow.

Good enough?

Toast for breakfast

How many nations do you depend on when you toast your morning bread?

My cheap $15 toaster’s case is mostly galvanized (zinc-coated) steel, with white exterior surfaces thanks to a thin enamel covering. Common traditional toasters, many still in service, are chrome-plated steel. The ends of mine are white plastic with red lettering.

The bread rack inside is also chrome- or nickel-plated steel, although in mine there’s also an aluminum support system. Stainless-steel (a chromium-iron alloy) screws and rivets hold the whole thing together. A nickel-chromium alloy, in strips wrapped around a mica sheet or mica-paper board, does the work. Nickel-chromium has high electrical resistance—it doesn’t conduct electricity well, so when a current flows through it, it gets hot.

Differential thermal conductivity comes into play again, in the thermostat, which may be a simple bi-metallic strip (usually steel and copper). The two metals heat up at different rates, forcing the strip to bend. This action in turn effectively flips a switch to turn off the heat and release the rack so it pops up.

The wire that leads to the electric outlet is copper, insulated by flexible plastic.

Some of the raw materials that make the toaster come from domestic mining, but the U.S. depends on imports for most of the materials.

Bauxite (aluminum ore) – 100% dependent (from Jamaica, Brazil, Guinea, and 5 others)
Nickel – recycling + imports = 72% (from Canada, Russia, Norway, and 18 other countries)
Chromium – recycling + imports = 100% (from South Africa, Kazakhstan, and 12 other countries)
Mica – 16% (from Canada, China, India)
Oil and refined products for plastics – 58% (Canada, Mexico, Venezuela, Saudi Arabia, and 64 other countries)
Titanium dioxide pigment – U.S. exports, but depends on 77% imports for titanium metal (South Africa, Australia)
Antimony (flame retardant in plastic) – 86% dependent (China)
Copper – 33% to 43% dependent (from Chile, Canada, Peru, and 12 others)
Zinc for galvanizing iron – 73% dependent for zinc metal (Canada, Mexico, Korea)
Iron ore – U.S. just about breaks even: a small exporter some years, a small importer in other years.

We’ll save the bread itself, together with the electricity to run the toaster, for future posts.

So how many countries in your toaster? Canada, India, South Africa, Russia, Norway, Mexico, Kazakhstan, Chile, China, Jamaica and the U.S. – eleven countries at a minimum.

Photo by Donovan Govan, used under the GNU Free Documentation License.

Consider the fork

Perhaps your family heirloom cutlery is sterling silver (that is, 92.5% by weight silver and 7.5% copper), but most likely your “silverware” consists of stainless steel.

Stainless steel has been around for only about 100 years, although chromium’s corrosion resistance in iron alloys was known by the 1820s. In the 1910s metallurgists invented ways of reducing chromium’s carbon content to make commercial stainless steel possible. Chromium makes steel “stainless,” not literally true, but such alloys are far less likely to rust.

Chromium finds its greatest use in stainless steel alloys, but dinnerware represents a tiny portion of end use. Structural elements in cars, aircraft, and appliances, together with building construction, take huge volumes of stainless steel. Most stainless steel alloys contain 10% or more chromium, with iron proportions at 70% to 90%.

While iron and chromium dominate the chemistry of stainless steel, your knife or fork probably contains other metals that make the alloy more machinable, resistant to abrasion, or simply more shiny. Nickel, manganese, molybdenum, titanium, and aluminum all contribute desirable properties to stainless steel. Dinnerware alloys commonly contain nickel (10%) and chromium (18%) combined with iron (72%). Nickel makes the alloy stronger, and chromium increases hardness along with its corrosion resistance.

The U.S. has no primary chromite (iron-magnesium chromate, (Fe,Mg) Cr2O4, chromium’s principal ore) production from mines, but our import dependency is only 39% thanks to a remarkable 61% of supply generated by recycling. Imports come mainly from South Africa and Kazakhstan, which together with India produce three-quarters of the world’s chromium—one of few elements whose production isn’t dominated by China.

Chromium metal hit record prices in 2008, averaging $11,078 per ton. U.S chromium consumption is declining with the recession, but in 2008 we used more than 400,000 tons worth more than $1 billion. With prices like that, it’s no surprise that one chromite deposit about 10 miles south of Coos Bay, Oregon, is being evaluated and permitting is in the works. Additional chromite reserves exist in the 2.7-billion-year-old Stillwater Complex of south-central Montana.