Thursday, July 31, 2014

RUBIES!

The US Geological Survey does not employ gemologists – while there have been several within our ranks historically, they have been amateur gemologists who have pursued their interest on their own time. Nevertheless, gems DO come from the ground, and could reasonably be construed to be an ultimate product of geology. The following question is typical of the kind we receive about gems.

Q:           Is there somewhere in California near Modesto that I can have a rock collection looked at? We are almost positive that we may have found some raw rubies! They have passed the scratch test and are very heavy and hexagonal shaped. 209-xxx-xxxx
- James

A:            We can't do gemology for you - the US Geological Survey is tightly constrained to work on only particular national objectives that Congress sets, including mineral resource assessments, volcano hazards, etc. 

My recommendation to you is that you contact a local gemological society and ask for guidance. I would NOT recommend going to any jewelry store, as they only focus and specialize on the end products. 

You might try:
http://www.americangemsociety.org/ ... but keep in mind that this is a trade association of retail jewelers, independent appraisers, suppliers, and selective industry members, and only incidentally will they have any component that might be of help to you. 

           You would probably do better with:

...or even better with a local society of educated amateurs, like the San Diego Mineral and Gem Society:

Finally, please keep in mind that there are beryls and other igneous minerals like garnet and eudialyte that can easily be mistaken for rubies by inexperienced people. A true ruby is a pink to blood-red (so-called “pigeon blood”) colored gemstone, a form of the mineral corundum (aluminum oxide). Ruby has a hardness of 9 on the Mohs scale, and is considered one of the four precious stones, along with sapphire, emerald, and diamonds. The red color in a ruby is caused mainly by the presence of the element chromium in the crystal lattice.
~~~~~


Thursday, July 24, 2014

The Dust Bowl, King Solomon, and Country-Western Music

Sometimes – even after all these years – I am amazed to learn of yet another series of cultural connections all tied together by geology. The following Q&A is just one of many examples of this. Another example is how modern Venezuelan politics and its history are underlain both literally and figuratively by its ancient Archaean geology. This Venezuelan example would take too long to share here, but it can be found in a book my wife and I have written titled “2 Worlds, The Real Venezuela: Living on the Edge of the Jungle and the Rise of Hugo Chavez” (http://www.barnesandnoble.com/w/2-worlds-the-real-venezuela-jeff-wynn/1112567534?ean=9780615428444). By the way, the girl holding the monkey in the cover photo is our youngest daughter.

Q: I just watched a show on the history channel. Part of the show covered the "Dirty 30's" and how the "Dust Bowl" helped shape human kind today. My question is, of the possible millions of tons of top soil blown away. Where did it go? Did the eastern sea board states get a foot taller during those years or what? Thank you for taking the time to answer my question.  Sincerely,
- Bart A

A: The Dust Bowl was caused by improper farming practices that destroyed the native prairie vegetation and their root systems - and didn't replace them. The US Soil Conservation Service (Now the Natural Resources Conservation Service, or NRCS) was created to first understand, then mitigate the consequences of plowing fields in prairies. In 1933, its original incarnation the Soil Erosion Service was created within the Department of the Interior, with Hugh Bennett as chief. Bennett was a visionary soil expert who had been publishing scientific papers on the subject since the beginning of the 20th Century. He practically invented soil science.

       To answer your specific question, yes: the soil goes elsewhere, and other places grow “taller”, though you might not be able to easily recognize this. Winds tend to scour certain localized areas, and then distribute the soil and dust outside these areas - but much more widely. Thus it may not seem like parts of the rest of the country developed deeper soils, but they did - though very marginally. The airborne distribution process drops out the heavier particles at shorter distances, while the finest dust can theoretically blow around the world. You might speculate where some of the dust that always seems to find its way into your house originally came from.

Two anecdotes may help you understand this better.
1. Satellites can see dust from the western Sahara blow thousands of kilometers out into the central Atlantic Ocean. Ultimately it collects in the abyssal ocean depths, where coring has actually measured it and its growth rate. It may even have a part in the Atlantic Hurricane development process.

2. While I was working in central Saudi Arabia two decades ago, I was asked to provide geophysical assistance to a geologist trying to evaluate a small ancient mine (SAM) named an-Najadi. This mine was one of at least 852 small artisanal gold mines found in Saudi Arabia today, and apparently formed the major source of gold reported in King Solomon's treasury.

    While visiting the site I saw that the geologist had used a backhoe to dig trenches. His objective was to get down through the soil to the bedrock, to figure out what the bedrock structure was - so he would know which direction to point or orient his evaluation drilling program. At the bottom of one trench I saw two round stones - they turned out to be grindstones used by the ancient miners to crush the quartz grains holding the tiny fragments of gold that the miners were after. I am looking at those two stones in my office as I write this.

    On the sides of the trench I saw three white lines, and asked the geologist about them. They turned out to be slaked-lime floors of ancient dwellings. I could see the oldest one, then one a meter higher stratigraphically above it - that therefore had to be at least a thousand years younger - and then one above that. The trench was 14 feet (4+ meters) deep. The lowest level was occupied by miners in Solomon's time - 3,500 years ago. The 14 feet of soil above the lowest dwelling level arrived since that time and is called "loess", a German word for blown-in soil. Most of this soil had been blown in from the west. It had come from the eastern Sahara, and crossed the Red Sea to get there. I have personally experienced sand storms in that area that kept aircraft from landing - because pilots could not see the ground for up to three days at a time. Operation Desert Storm in 1990-91 was rushed forward in time to beat these seasonal wind storms called the Shamal. These storms happen during the period of monsoon storms that lash the Arabian Sea for several months in the Spring every year.

    This all tells us that over-grazing in the proto-Sahara, starting thousands of years ago, had already stripped most of North Africa of its protective vegetation, leading to the ever-expanding "desertification" process we see that continues today... and which Oklahoma experienced for a short period in the 1930's.

    Soil conservation is an important lesson we learned from the Dust Bowl of the 1930's. Some of the Oklahoma economic refugees migrated to California, and a country western band leader brought his musical tradition from there - and lived across the street from me when I was a child in Bakersfield, California. I still remember Bakersfield being one of two major Country Western music centers in the country after Memphis... and I can still remember the disparaging name of "Okies" being used for these poor migrants decades after they arrived.

    I hope this answers your question, and perhaps puts it in a wider context.

Tuesday, June 24, 2014

Hot Magnetic Oxygen Water World

There is another version of the Anthropic Principle, one that applies only to the planet Earth. We may be more alone, or unique, in this universe than the Drake Equation - the calculation of the possibility of other life out there in the universe - may have led us to believe.

The deepest hole ever drilled into the Earth's crust reached down to about 7.6 miles (12 km) below the Kola peninsula of northern Russia. The technology available to humankind cannot get below that depth (and that depth took 24 years of drilling and billions of Rubles to achieve). The rocks are so hot and plastic with overlying rock pressure at those depths that the hole closes in on the drill bit - and partially fills the shaft back in from the sides as the bit is drawn back to the surface to be replaced. So... the maximum depth achieved by humanity's best effort is less than 1/10,000 the Earth's diameter, or the distance of a short commute on a Monday morning. We actually know more about galaxies, comets, and the moons of Jupiter and Saturn than we do about what lies below our feet on our own planet. No matter how you look at it, we cannot really touch virtually all of the world beneath our feet.

In other words, everything we think we know about the interior of the Earth is obtained by very indirect means, and a lot of this is from mathematical modeling.

To see below the depth of the Kola well, we must rely in electrical geophysical methods like magnetotellurics (which is one of the things that I "do" as a geophysicist; it can detect resistivity layering down to perhaps 50 km or so), and on earthquakeseismology. For nearly a century seismologists have traced the powerful vibration signals from very large earthquakes as these signals propagate and refract through the Earth. By comparing the time of arrivals elsewhere around the planet - and whether just P-waves, or P-waves and S-waves together make it - they can discern contrasts in density and other physical parameters as these change with depth. P-waves (or primary waves) are pulses of energy, momentarily compressing the material they pass through. It's the blast wave from an explosion expanding outward. S-waves (or secondary waves) are shear waves, oscillating material back and forth, sideways, as they pass through the material. Think of how you would move your hands forward and backward to tear a piece of paper. A key feature of S-waves is that they cannot propagate through a liquid. Think of trying to use your hands to tear water. By the 1920's seismologists had used the initial earthquake seismic information and some density calculations to conclude that there is a solid iron core to the Earth, surrounded by an outer liquid iron part of the core. The outer liquid core is overlain by a hot and plastic Mantle, and finally by a relatively thin crust serving as a very thin solid shell above them both. All living things live on or just beneath the top of that crust.

The methodical genius who first figured all this out was a quiet Danish lady named Inge Lehmann, who died in 1993 at 104 years of age.

Seismology and magnetotellurics show us the layering in the Earth with depth. Indirectly we also know that the center of the earth is very hot. After all, there are volcanoes and fumaroles, and the deeper you mine in places like South Africa the hotter it gets. Nearly everywhere scientists have measured temperature in wells, a thermal gradient exists: deeper means hotter. But we also know there is a lot of heat below us for several other reasons, including plate tectonics. SOMETHING has to be powering whole continents to be able to wander around. And then there's the magnetic field of the earth.

What distinguishes Earth from Mars and the Moon? A magnetic field, an atmosphere, liquid water - and life. The last requires the first three in our limited observations so far. Without a magnetic field to deflect it, Solar radiation would  sterilize the Earth and disrupt any attempt for life to gain a foothold. Solar radiation would also strip away any atmosphere, which is apparently why Mars doesn't have much atmosphere left to speak of. Mar's atmosphere is only a few percent of the density of our own atmosphere - though there is evidence of much more at one time in the distant past.

What distinguishes Venus from the Earth? Venus has an atmosphere, but it has fallen under a runaway Greenhouse Effect - too hot for water and in fact so hot that raw sulfur is a liquid on its surface. The Earth lies in what is sometimes called the "Goldilocks Zone" where it's not too hot and not too cold, between roasting Venus and frigid Mars. Water on Earth not only exists, but can exist in all three states (solid, liquid, and gaseous). This is not so for Mars or Venus, neither of which has a magnetic field, nor plate tectonics, nor significant water.

It has been apparent for quite awhile that the Earth's magnetic field is the reason why life exists on our planet. A magnetic field, however, requires some sort of dynamo to create and sustain it. How to power this? Well, if there are enough radioactive elements - or sufficient heat from the collapse of the proto-planetary disk to form our planet - well then maybe there is enough energy to drive a dynamo. However, this requires a lot of assumptions that scientists cannot test - they can't drill deep enough.

There is another problem: hot things tend to cool when surrounded by colder things... like interplanetary space. A magnetic field driven by an internal dynamo cannot last forever.

Hot things cool in two ways: by conduction and/or by convection. Conduction is like the metal pot you cook your cream of wheat in. Heat transfers from a hot source beneath to a cooler part above without any motion of particles involved. With convection, however - the bubbling cream of wheat - the heat is transferred by particles moving in three-dimensional loops called hydrothermal cells. You see them as bubbles driven by steam in the sauce pan. A hotter particle of the wheat from the bottom, in contact with the metal pan, rises because it is hotter (and thus less dense) than the particles above it, thus transferring heat from the bottom to the top of the cream of wheat. If the stuff cannot convect - if it's not liquid enough - then it will get hotter and hotter until it burns. It not only tastes terrible, but the sauce pan is a bear to clean up afterwards. In the same way, the solid iron core can only conduct heat out; like the metal sauce pan it cannot convect heat. However, the liquid iron outer core and the hot and plastic mantle above it can convect heat - and these convection cells of highly conductive material must be the source of the magnetic dynamo. The convection cells in the mantle are also what's driving whole continents around across the face of the Earth.

Remnant magnetization in rocks 3.5 billion years old, however, proves that the Earth's magnetic dynamo has existed for at least that long. The oldest known life is found in stromatolites - clumps of cyanobacteria - just about that old. This is not a coincidence. If there was no protective magnetic field, the stromatolites and then algae (and Earth's atmosphere) would not have survived Solar winds and radiation. But 3.5 billion years is a long time for something to stay hot enough to drive a magnetic-field-producing dynamo. Older computer models based on relatively low thermal conduction assumptions for iron seemed to suggest that it would take awhile for the solid iron core to give up its heat. This could conceivably sustain a dynamo lasting that long.  According to these older models, the heat from the core would take billions of years to conduct out to the outer liquid core and Mantle where a different form of heat transfer - the much faster convection - takes place.

In the last several years, however, scientists have been forced to re-evaluate what they think they know about the center of the earth. Several years ago, another piece of information became available from some Japanese extreme-high-pressure experiments. Iron at pressures and temperatures we calculate must exist in the center of the Earth has a far higher thermal conductivity than anyone had thought could be possible. According to milecular orbital theory, if you smash material together hard enough, it frees up electrons and changes its conductivity. This means that the Earth's heat-driven dynamo should have burned out billions of years ago. In other words, the Earth's magnetic field would have then died, and the atmosphere and any nascent life would have all disappeared before most of the geologic record could even take place. Think of dead Mars.

Speaking of geology, fluid and gas inclusions in ancient rocks tell us that around 2.5 billion years ago the Earth's primordial atmosphere of CO2 and nitrogen transitioned to an oxygen-nitrogen atmosphere. The world as we presently understand it began then. In part we can blame this on the stromatolites and photosynthesizing plant life that was expanding at that time.

In the 1970's a few scientists offered what seemed like a ridiculous idea: the Moon formed well after the Earth formed. It formed in its current size and shape when a large Mars-sized planetoid crashed into the proto-Earth and splattered material into space around the Earth. That material blasted into multiple orbits then coalesced to form the Moon, leaving a very different - and very hot - planet Earth behind. Computer models show that this is easily feasible. If so, then the Earth would have glowed like a small star from the massive infusion of heat from all the kinetic and potential energy of the collision. This idea is now taken seriously for several reasons, but mainly because the rocks on the Moon are sooooo much like the rocks on the Earth, and sooooo different from rocks on Vesta, Ceres, Mars, and Venus. We can discern these by optical spectroscopy, coupled with sampling meteors that the spectroscopy says must come from those places.

Could that ancient impact hold the answer for why we have such a long-lasting magnetic field around our planet? That seems to be the best explanation at this time. If so, then life exists on this planet because of some pretty amazing circumstances: 
  • it exists in a narrow Goldilocks Zone, 
  • it was given a huge heat boost by a collision from a large planetoid, and 
  • its crust was given a lot of water from impacting comets that allowed it to be less solid, more flexible, and have an ocean of liquid water. 
  • Photosynthesis then started early and gave this planet an oxygen-nitrogen atmosphere, and finally
  • The Earth's magnetic field lasted a very, very long time.


Those are a lot of things that had to come together at just the right time for life to form and evolve here.

There are so many coincidences - like the Anthropic Principle that allows molecules - and thus life - to exist. It seems remarkably like our Earth has its own local version of the Anthropic Principle: just the right features and additions at just the right times to allow life to form and evolve over an extended period of time.

Bruce Buffett, a geophysicist at Berkeley puts it this way: "The more you look at this and think about it, the more you think it can't be a coincidence. The thought that these things might all be connected is kind of wondrous." (Discover, July/August 2014, p. 41)


With all the exoplanets being found in solar systems nearby in the Milky Way Galaxy, what is the likelihood that one of them could have all these coincidences? Since Galileo, humanity has been humbled to know that it isn't the center of the universe. 

However, it appears that we certainly are unique.
~~~~~

Friday, June 6, 2014

Windshield Time

Q: Thank you very much. Your answer was more than adequate. Not only did you answer my primary question but also preemptively answered some follow-up questions I may have come up with.
My only remaining question is how the extremely deep oil reservoirs they are finding were formed. I've read some of the oil is at depths that would seem to pre-date the Carboniferous age.
I'm a plumber but I love pondering things such as this during my frequent "windshield time ". I appreciate you taking the time to explain this to me and to do so in a way I can understand.
Thank you very much,
- Patrick D

A: You can call yourself a "Plumber" if you want, but you are clearly and instinctively a natural scientist. That's the only definition that would apply to someone who ponders the world around them to such a deep extent during "windshield time" as you call it. I was involved on an expedition that crossed the Empty Quarter desert in Saudi Arabia and had two formally-designated scientists (we had PhD's). However, most of the other 15 expedition members got deeply into what we were trying to map at the Wabar asteroid impact site (Gene Shoemaker and I published this in an article in the November 1998 Scientific American). Our expedition companions first started asking questions, then offering ideas - and as a scientific TEAM we did the partial crater excavations and the surface mapping of the site. There were 17 people on that science team.

To answer your other question, there was carbon on this planet from its original formation. Some is magmatic in origin - things like carbonate volcanoes, or crystallized carbonate magma more commonly called "carbonatites".  This is primordial carbon that is thought to come from the mid-to-upper mantle. There is a carbonatite in southwestern Afghanistan that stands out from the surrounding rocks both chemically and structurally like a big red flag. There is another, a real monster, in southern Venezuela (Cerro Impacto is ~10 km across, but is NOT an impact feature). These things often have unusual levels of Thorium and Uranium in them, often in concentric zones. There are also Kimberlite Pipes - these are generally but not always tubes that carry diamonds up to the surface from the upper Mantle.

However, most oil & gas deposits come from sedimentary deposition of swamps and their occupants during ages that reach back as far as life existed. The carbon in the vegetation and animal life was buried to increasingly greater depths by later sediments, sequestering it and getting it out of the atmosphere. This usually happened in large basins, and the accumulating weight of these sediments often caused the basin to bow and get deeper in the middle. As an example of how fast this accumulation can happen, I was visiting an ancient mine site in the western Arabian peninsula. This was one of ~862 small ancient mines that provided King Solomon with his gold about 3,500 years ago. In that 3,500 years, dust and sand blowing across the Red Sea from the Sahara have buried the original mine site in nearly 4.5 meters (14 feet) of loess, silt and dust that we now have to dig down through to access the original shaft. And this accumulation was on flat ground! When surrounded by eroding mountains, a basin’s sedimentation can build up much faster than this.


With increasing weight overlying organic-containing sediments, both pressure and heat rise. Natural temperatures at the bottom of a 12,000-ft diamond mine in South Africa are about 60 C (140 degrees F). Eventually you get enough heat and pressure to "cook" the organic sediments - oil geologists call this process "maturation" among other things. When converted to a liquid these relatively less dense, carbon-rich fluids (oil and gas and water) tend to migrate upward, following weak zones in the sediments overlying them. They will do this until they either escape (the Gulf of Mexico is full of natural "seeps") or they get to a blockage that traps them: for instance some sedimentary salt from a dried-up ancient sea. THIS kind of natural trap is what the oil companies are looking for using sophisticated seismic prospecting and imaging systems.  
~~~~~

Wednesday, May 28, 2014

Seafloor Ooze, Subduction, and Oil

When I was a young man, I thought that having my PhD meant that I was now a scientist, that the advanced academic degree was somehow the dividing line between scientist and not-scientist. If I had been a little better at history, I would have realized that some of the greatest minds in science – people like Michael Faraday and James Clerk Maxwell – did not have PhDs. What they DID have was a tendency to think about things. The following two queries came from someone I call Patrick the Plumber Scientist.

Q: I've read the seafloor  "ooze" contains a fair amount of carbon based material. When this ooze is carried along with the seafloor downward in subduction zones wouldn't the combination of heat and pressure along with the presence of water form hydrocarbons aka oil?
- Patrick D

A: You are an unusually thoughtful person to arrive at that conclusion. Not all the ooze, as you call it, actually goes down with the subducting oceanic crustal slab – some of it gets scraped off and in some cases rafted onto a continental margin. You can find some of these strange remnants on the northern California and southwestern Oregon coastal area, among many other places in the rest of the world.

At some point the carbon from the seafloor muck that DOES go down with the oceanic crust probably passes through an oil/hydrocarbon maturation phase, but at depths and circumstances where it could not be economically extracted (even if it could be located). The muck continues down even deeper with the oceanic crustal slab to depths where even greater heat and pressure subsequently break it down to even more primitive constituents. With the water and sulfur also found in these seafloor sediments, this leads to partial melting – the lighter constituents rise through the crust (like a lava-lamp), somewhere in-board of the subduction zone to form volcanic chains like the Cascades, the Kamchatka Peninsula, the Andes, the Indonesian Archipelago, etc.

The magma that actually rises is driven at least partly by CO2 and H2S gases that derive from that original seafloor muck and seawater. These constituents, along with the iron, manganese, and silica of the Mantle, comprise the rising magma.  As it comes closer to the surface of the Earth, the pressure decreases and the gases come out of solution (like uncapping a bottle of soda) in that rising magma to form bubbles. This has been studied in one of our laboratories in a hot-high-pressure cell. The increasing nucleation of bubbles expands the magma volume and this causes the whole mix to accelerate upward faster and faster toward the surface. There it can often reach a runaway explosion that we call a Plinian eruption (named after Pliny the Elder, who died at Herculaneum trying to rescue friends during the eruption of Mt Vesuvius). This bubble-filled magma becomes a froth exploding violently upward into the atmosphere; it cools in the air to form the ash and tephra that (along with effusive lava) form the slopes of stratocone volcanoes like Mt Fuji, Mt Hood, and Mount St Helens.


Volcanologists work hard to measure and track volcanogenic H2S (the burnt-match smell) and CO2 gases to get a sense of where a restive volcano is in its possibly-pending, probably-not eruption. When Mount St Helens erupted in 2004-2006, it was relatively non-violent (though you would have died if you had been inside the crater at the time). An earlier almost-eruption in 1998 never quite reached the surface. Seismologists could see the volcanic conduit below MSH "light up" with the rock-breaking activity of a magma approaching the surface, but it never broke through. In the intervening 6 years, apparently these gases largely escaped, reducing the explosive danger from the volcano when it finally did erupt on October 1, 2004. One way to know if the CO2 is volcanogenic, or from the modern atmosphere, is to measure its isotopic makeup. Atmospheric CO2 has 14C ("Carbon-14"), 13C, and 12C isotopes. Volcanogenic CO2 has only Carbon-12 (12C), the stable isotope in it. The other two radio-isotopes have long since decayed during the millions of years passed while the carbon was deep inside the Earth. 
~~~~~

Friday, May 23, 2014

When Will the World End?


I have received episodic queries asking if the world is about to end? Sometimes these correlate with apocalyptic movies being released. Sometimes they are triggered by an uneducated conspiracy theorist (an oxymoron) somewhere with nothing better to do than to look at seismic data freely available on the web. For instance, does the latest seismic activity in Yellowstone portend the end of the world? That one turned out to be an instrumentation issue not understood by the conspiracy theorist. Do the huge earthquakes off the coast of Chile and Japan mean that the End Times are approaching? We’ve all seen trailers for movies like “Volcano” (“The Coast is Toast”), and “2012”, and I have little patience with these attempts to make money.

But when will the world really end?  Or at least become unrecognizable to us, or even uninhabitable?

Current understanding of the evolution of the Sun suggests that it is about 5 billion years old and will likely continue burning for another 5 billion years. It may start fusing helium to carbon and turn blood red before then, but the time is so distant as to be irrelevant to us.

What about things heading south on somewhat shorter time scales? An article by Wolf and Toon (http://onlinelibrary.wiley.com/doi/10.1002/2013GL058376/abstract) suggests that there will first be a “moist greenhouse runaway” event, followed by the loss of all water from the surface of the Earth, followed by a runaway thermal greenhouse situation – like Venus is currently experiencing. The Sun increases its energy output by roughly 1% every 100-110 million years. In other words, it will continue growing slowly hotter on the planet Earth (see an earlier chapter on the Faint Young Sun Paradox here: http://askageologist.blogspot.com/2012/06/snowball-earth-faint-young-sun-paradox.html).

As solar output grows, the Earth’s surface temperature should steadily rise. When it does, water vapor concentrations in the lower atmosphere will increase, and this will lead to an increase in water vapor in the Stratosphere. Solar radiation there will break down water molecules, and the Solar Wind will then blow them away into space, leading eventually to a waterless surface.  This may be what happened to Mars billions of years ago, made to happen faster and earlier due to its weaker gravity. 

Some earlier research had suggested, based on computer simulations, that a “moist greenhouse runaway” process would start about 170 million years from now, and that a full thermal runaway (the “Venus Effect”) would start around 650 million years from now. However, Wolf and Toon factor in ocean-atmosphere moderating effects from those same surface waters, and calculate something more like 1.5 billion years before the onset of the “moist greenhouse runaway” event. 

Somehow I find this difficult to worry about.

What about bad things happening on shorter time scales? For instance, what is climate change really leading to? There is no shortage of either Climate Doomsday or Climate Rubbish prophets. A recent article in EOS (Transactions, American Geophysical Union, Vol. 95, No. 18, 6 May 2014, Wuebbles et al, link here: http://onlinelibrary.wiley.com/doi/10.1002/2014EO180001/abstract) provides several illuminating graphs included here for interested readers. Figure 1 shows the severity of weather in the United States on a decade-by-decade basis starting in the 1950’s. It’s hard to argue with a graph like this: climate change is clearly well underway (see the earlier chapter on Climate Change – is it real? Here: http://askageologist.blogspot.com/2013/07/climate-change-is-it-real.html).

Figure 1. Extreme weather events in the United States by decade since the 1950's (Wuebbels, et al., 2014).

Figure 2 actually lays out the consequences for climate change: what things will look like for different parts of the country for the 2070-2099 timeframe. A short summary: it all gets hotter (no surprise), and the precipitation generally increases (surprise), except for the southwest, where precipitation will decrease (no surprise). More and greater hurricanes are projected (no surprise), but the numbers of severe tornadoes and severe East Coast winter storms have not increased in six decades and may not with the increasing CO2 and methane in our atmosphere (surprise). The minimum temperature in Alaska will be between 12 and 15 degrees (Celsius) warmer – not bad for people like me who don’t like white stuff on the ground. Perhaps more surprisingly, the northern tier of the Continental United States will get warmest – by about 6-11 degrees Celsius by the end of the century. Mean precipitation will stay pretty much the same in the Southwest – but it will be 6-8 degrees Celsius hotter, leading to drier conditions even with that precipitation. This will make those Phoenix afternoons somewhat less survivable as the century develops. 

Figure 2. What we can expect, region by region, from climate change if CO2 and methane continue to be produced by fossil fuel consumption at current rates (Wuebbels et al., 2014). 

What about economic impacts? The American Breadbasket of the central and northern plains will be seriously threatened by increasing drought conditions. Perhaps we should stop wasting 10% of our corn crop for ethanol. 

What can anyone do on their own? You should consider investing in land in the Canadian Prairie Provinces – but NOT anywhere near a modern coastline. Estimates of seawater rise vary – but they are all on the positive side, and low-lying areas like the Jersey coast, Florida, and New Orleans will be the Big Losers. An attempt to rationalize flood insurance following Hurricanes Katrina and Sandy lasted just two years – then appeals to congresspersons for relief from dramatically increased flood insurance rates “won” again. The end result is that people are rebuilding low-lying areas, and the American taxpayer will be expected to bail them out at enormous expense yet again.  Hurricane by hurricane. Science deniers apparently don’t believe in gravity, either.

Ultimately, if the world was going to end in 1,000 years, how would that be different from 1,000,000 years or 1,000,000,000 years? How would you change your life?

If you’re rational, you would not worry about the End of the World too much - unless you live on the Jersey Shore, or Florida, or New Orleans. If you are both rational and responsible, you would consider replacing your gas-guzzling SUV for something that gets better mileage. If you are still bothered, go help at a Sharing House for people who cannot get enough to eat, and you’ll feel quite a bit better afterwards.  

You will have increasing opportunities for this with time.



Friday, May 2, 2014

Aquamarine

Some people may be sitting on a gold mine – literally. I’m acquainted with some once-hard-scrabble ranchers in Arizona whose lands sat atop what would eventually become a gold or copper mine. They live in large houses and drive late-model pickups now. Other people may have stumbled on a rare fossil (a woman in Montana accidentally stumbled onto what turned out to be the most complete T Rex fossil ever found), or a rock that turns out to be a gem in more ways than one. 

Q: I have an aqua marine stone, approx 15 pounds . I would like to know it's value.
- Terry M

A: If you mean "aquamarine", then there are several possibilities:
a. a pale blue or greenish gem variety of beryl,
b. an aquamarine sapphire,
c. an aquamarine topaz, or
d. an aquamarine tourmaline.

15 pounds of any of these would be worth quite a bit, depending on the grade and quality. However, in the US Geological Survey we do highly applied research in geology and geophysics (some field offices work on ecosystems and biology). We have very specific line-item assignments in this agency, assignments set by Congress, and they do not include dealing with gem stones. As a result, we have never hired a gemologist per se as far as I know. 

I wish I could provide more help, because this is fascinating to me. In Bangkok, Thailand, there is a Wat (temple) that houses something called the "Emerald Buddha" that is apparently a carved statue of rough-grade emerald. In several senses of the word, this is a priceless artifact. Your stone would not be on par with this (it's not carved or sculpted I assume), but it is still worth something - if only as a source of material that gemologists can cut/extract high-quality raw gems from.