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.

My battle with “of”

I think scientists generally put lots of “ofs” in their writing. At least I do. I know it, I hate it, and I still do it.

Combined with the discovery of the vast copper resources of Chile, this spelled the beginning of the demise of the copper business of the United States. 

One of my first editors, my friend Sally Lawrence, read that line (and the plethora of other prepositions I had peppered my prose with) and wrote “Oh woe is me—prepositions are the downfall of many a good geologist.” I find now that I must force Word to highlight all my “ofs” so that I can ruthlessly, tediously reduce their number. I have trouble avoiding the word: I’m so accustomed to writing things like “the geology of Canada contributed to its position as one of the world’s leaders in production of mineral resources” – yikes! When I see that now, I really cringe! (But only when I’m on alert, in editor mode, and watching for such literary atrocities.)

But at least overuse of “of” can be repaired. Or maybe I should lose the “ofs” and say “I can overcome this problem.” Sometimes.

I’m prone to happily split an infinitive here and there, and I agree with Winston Churchill’s lines ending in prepositions, at least occasionally. And “of” is a useful and necessary word. I’m just trying aggressively to improve my writing by controlling its unchecked spread.

I hope you like the revised sentence about Chile’s copper. It may not be perfect, but at least it’s a little better, I think!

Combined with vast copper discoveries in Chile, decreased demand drove the U.S. copper industry into a long, generally downward spiral.

I live in a mining town

I live in a mining town. In some ways, the mother of all mining towns—the richest hill on earth, literally, and the only mining camp in the United States that grew into a multi-ethnic metropolis, with close to 100,000 people ninety years ago. In Butte, Montana, gold drew them, silver kept them, and copper made them rich.

When I look out my kitchen window I see a little park, the site of a small mine that shut down in 1910. Its waste rock makes the walls of my basement. And I see a massive headframe, the surface expression of the Anselmo Mine, one that reached 4,301 feet deep and closed in 1959. I’ve met Ed Panisko, a gentle man and a tough miner, the previous resident of my house, who worked in the Anselmo.

What Things Are Made Of didn’t come about because of my living in Butte. It started when I lived in Golden, Colorado, and was mostly an intellectual outgrowth of the perpetual calendar, History of the Earth, created in 1994. But Butte and its people have absolutely fostered and stimulated my work on What Things Are Made Of—in many ways, the core concepts of that book are nowadays right outside my door and in the foreground of my mind as I live and write and walk Butte’s streets.

Mining towns are complex, because they draw a transient population that depends on the vagaries of the mining business. Mineral commodities depend on all the things that drive the world economy. Wars are good (more copper, more iron, more manganese). Housing booms are good (copper pipes for plumbing) and busts are not (less gypsum for sheetrock, less feldspar for toilets). New inventions that connect and help humans are good (copper wires for telephone lines, tungsten for incandescent light filaments, mercury for Dr. Rush’s Thunderclappers, neodymium for electric car batteries). And so go the fortunes of places like Butte or Chuquicamata or Almaden or Bayan Obo or Udachnaya. 

Living in a historically vibrant mining town that today is part of the nation’s largest Superfund site (as well as the nation’s largest National Historic Landmark district) is a huge eye-opener for anyone who is conscious of both the needs for mineral resources and the damage their extraction can create. And, I hope, of the possible ways that damage can indeed be remediated. The Clark Fork Watershed Education Program exploits the historical needs, the damage, and the ongoing restoration, to foster understanding and stewardship in a complex environment. I’m quite proud to have an occasional small role in that organization’s outreach to thousands of K-12 students and teachers.

In Butte, I live at the corner of Quartz and Crystal Streets, a very cool spot for a geologist. That’s one of the aspects of Butte that contributes subliminally to What Things Are Made Of.

I’m a person who craves the frontier. I grew up at a time when the American frontier had evaporated: I tried California’s golden magnet, but the frontier was gone. Space might have worked, but I wasn’t able to be an astronaut. Butte’s history, its color, its intricate flavor, is my personal frontier now. It touches all I do.

Photos by Richard Gibson

The most valuable mineral commodity

Before you read on, take a guess. What non-fuel mineral commodity adds up to the most valuable mineral industry in the United States? “Non-fuel mineral commodity” means minerals, metals, rocks, natural mineral-rich solutions, stuff taken from the earth other than oil, natural gas, and coal. And not water.

Here’s a hint: it’s not iron ore, not lead, not gold. It’s not silver, aluminum, or copper.

The most valuable mineral commodity was worth more than $13 billion in the U.S. in 2008, but its average price was just $8.98 for a ton. We used almost 1½ billion tons of this common stuff, and had to import a bit (just 2%) of what we used, mostly from Canada, Mexico, and the Bahamas.

Every state produces it, from more than 4,000 sites operated by more than 1,600 companies employing more than 80,000 workers. Texas, Pennsylvania, and Missouri are the top three producing states.

This most valuable material declined in use by a third from 2006 to 2009, a statistic that may suggest that its uses relate to factors affected by the recession. Indeed, the greatest use reported for the commodity is in construction, mostly road construction and repair. What is it? Crushed stone.

Perspective

A 462,000-gallon oil spill such as the one near Port Arthur, Texas, in January 2010 is not a good thing. But it gives a good opportunity for some perspective.

462,000 gallons amounts to not quite one minute’s worth of oil consumption for the United States. As of October 2009, we used up (forever) 546,204 gallons every minute of every day (EIA data), and that's with US consumption down by 2 million barrels a day or so from 2007, thanks to the recession.

In terms of world oil consumption, this spill represents just over 11 seconds in the planet’s oil-guzzling day.

Where uranium comes from

You all know what uranium is used for: nuclear weapons and nuclear power. Some volumetrically tiny but nonetheless important uses include x-ray generators, inertial guidance systems, glass coloring agents, and age-dating in geology.

The mystique of secrecy and national security surrounding uranium and its products might lead you to think the United States produces—and jealously guards—all that we need. Nope. Although the U.S. is the consumption leader, using 30% to 40% of world uranium in recent years, U.S. production totals only about 3% of world supply.

In 2008, 85% of U.S. uranium consumption was imported, an import dependency greater than that for oil.

Canada extracts the most uranium of any country, and has the greatest known reserves. Australia is second-place producer, with Kazakhstan, Niger, and Russia in a near-tie for third place. Kazakhstan is second in reserves. The U.S. imports uranium from Canada, Australia, Russia, Kazakhstan, Namibia, Uzbekistan, South Africa, and elsewhere.

Economic viability of uranium mines in the U.S. depends sensitively on the price. Wyoming and New Mexico together have some 700 million pounds of uranium reserves if the price is $50 per pound, but only around 175 million pounds at $30 per pound. In January 2010 the price was $44.50 per pound, but uranium prices from 2004 to 2007 fluctuated widely, from $15 to $138 per pound. Volatile prices are the bane of the mining industry, which requires long lead times, huge up-front investment, and complex infrastructure.

Nuclear power plant image from Wikipedia.

Big vs. Little

When I talk to people about natural resources, whether copper or cobalt or indium, a common misconception is that such commodities are evenly distributed across the earth, and we just have to find them—a mineral version of “drill baby drill.”

Countries like the US, Russia, China, Canada, Brazil, and Australia are relatively rich in a wide variety of mineral resources for a simple reason: they’re big. Big enough to have a lot of geology, a lot of environments, a lot of situations where economic mineral deposits can accumulate.

Small countries just don’t have the geologic diversity to be rich in lots of minerals—but lucky geologic accidents do occur, sometimes making a small country the world leader in one or two commodities.

For example, Spain and Italy together account for two-thirds of the world’s reserve base of mercury. Spain’s mercury mines were among the oldest mines of any type in continual operation (since Roman times) when they ceased mining in 2003 because of decreasing demand for mercury. Pumice, a volcanic rock used in building-block construction, spews from volcanoes all over the world, but Greece produces more commercial pumice than any other nation. Finland produces more than a third of the world’s peat. The US imports nearly a million tons of peat annually for horticulture, but next-door Canada is the main supplier rather than Finland.

Botswana’s miners find more gem diamonds than miners elsewhere, at 25 million carats per year, but Russia is a close second with 23 million per year. Botswana and adjacent parts of southern Africa harbor a disproportionate number of kimberlite pipes, unusual igneous rocks that transport diamonds from depths of 150 to 200 km beneath the surface—depths where pressures are great enough to squeeze carbon into diamonds.

Boron—used in glass, ceramics, soap, detergent, bleach, enamel, and other everyday products—comes from many countries (and the US is a net exporter), but the world leader is Turkey. In western Turkey’s Menderes Massif unusual concentrations of tourmaline, a boron mineral that sometimes makes gemstones, give thermal waters their remarkable boron content. Recent faulting seems to provide pathways for the hot water, which serves as a geothermal resource as well as a reservoir for boron.

Gem tourmaline photo from Wikipedia under GNU Free Documentation License.