Rock Types

Rocks can be generally classified into one of three general rock classes. The first two of the three classes are easy to recognize:
1. Sedimentary rock, formed in layers by the accumulation of weathered rock fragments and/or chemical precipitates, usually under, or under the influence of water (and sometimes wind),
2. Igneous rock, which includes volcanic lava, as well as related (coarse-grained) intrusive rocks such as granite, diorite, and gabbro.
3. Metamorphic rock. This is generally more difficult to characterize and understand because it is modified – a derivative of - one of the other two.

About 90% of the queries we receive on Ask-a-Geologist, typically accompanied by a photo and asking "what is this rock", we cannot usually answer. In general, the photos have no scale and are blurry, and the light doesn't show the finer structures well. A geologist would want to turn the rock sample over in sunlight with a hand-lens, looking for mineral grains and their distinctive crystalline form or "habit", and perhaps scratch visible crystals with a knife-blade to check their hardness to aid her identification effort.

The following is a rare case of a query accompanied by a good quality photo (it even had a coin to provide scale!) and enough additional context information to allow me to identify the rock.

Q:
Last weekend I climbed Mount Mansfield in Vermont. The higher we got, the more silvery the rocks looked. Attached is a picture, but it doesn't really do justice to the silvery tone. My friend wanted to know what caused the rocks to look so silvery.  I said I'd ask the expert.
--Valerie W

Photo: Yannick Guenet

A:
That's a schist. As in, that's a Gneiss Pile of Schist.  ;=)

Bear with me here – there is a point to this.

The silvery-ness that you see is caused by metamorphism, that is, a change to the character of the rock and its inclusive minerals. The word derives from metamorphosis – literally, change of form. Metamorphism usually is caused by the original igneous or sedimentary rocks being buried by tectonic forces at some time in their ancient past, but it could also be caused by hot fluids from a nearby heat-source (like an intruding granite body). Old-time miners would say that metamorphic rocks had been “stewed and cooked” – which is remarkably prescient.

The deeper a rock is buried, the greater the consequent increase in pressure - and also temperature – that it will experience. The photograph shows a complex rock that under great pressure has been deformed plastically – in this case, it is a schist. According to several sources (here's one: http://en.wikipedia.org/wiki/Blueschist ) this means depth of burial at one time reached 15 - 30 km before it was uplifted by tectonic processes and then exposed by weathering. The result of this high pressure/high temperature transformation process is that the original minerals are converted into several new minerals in a schist, commonly including glaucophane and muscovite - the latter is usually called white mica. Typically, there is plastic flowage going on, which leads to the alignment of the glaucophane and muscovite in the flow direction - and you can see this in your photo. The muscovite in these rocks, however, is usually very fine-grained - sometimes not easily visible even in a hand-lens. The net effect is to give the rock an over-all glossy look, and if you ran your hands over it, a slightly greasy feel sometimes. By the way, there are blueschist (blue-gray in color) and greenschist varieties of this rock. The latter are prominently greenish in color, because this kind of schist is loaded with chlorite and epidote: green, chlorine-rich minerals both derived from original black minerals such as pyroxene, and dispersed throughout the resulting rock as a whole by the metamorphic (“stewing and cooking”) process.

You describe the rock becoming more silvery with increasing elevation. That could be because the entire mountain is upside down from its original emplacement, and as you rise in elevation you are in fact walking deeper in time and burial depth. While this sometimes happens during tectonic processes, it is not very common. Though it seems more deformed, I suspect that in fact you are seeing a gradational change from an even more strongly metamorphosed rock, called a gneiss, found at the lower elevations of your hike. This kind of rock doesn’t have the muscovite “sheen”, but instead is typically devoid of chlorite and platy minerals. Gneiss commonly has much larger crystals - this is because the rock was so hot, and maintained for such a long time a great depth of burial, that everything re-crystallized. The longer a hot, fluid mush is held in place, the larger the crystals can grow. Gneiss is typically formed at 15-50 kilometer depths. I suspect that the original rock mass is still upright, and that you were in fact climbing up from deeply metamorphosed gneiss to less-metamorphosed schist above it.

~~~~~

Mount Lemmon is a spectacular uplifted mountain range located far to the south and west of Mount Mansfield - it lies just north of Tucson, Arizona. From the city, the face of the mountain has the broad texture and layering of the original sedimentary rock that it was made out of. However, up close it is coarsely crystalline and very much NOT (any longer) a sedimentary rock. As you move farther north in that complex you are moving ever deeper in original burial depth, and the gneiss turns gradually to granite – back to an original plutonic form. The original sediment probably was weathered out of a nearby, much more ancient granite complex. There is a famous story of a PhD student (Dr. Ed McCullough, who eventually became the geology department head at the University of Arizona) finding a blastoid (head) of a Paleozoic crinoid in the metamorphic rock while mapping the complex with other faculty. This story – and Mount Lemmon - neatly tie all three rock types together in one package.

~~~~~

Tsunamis, Rogue Waves, and Tidal Waves

Geology started out as the science of uniformitarianism: What we could see in the rock record is what we could expect to see in the future. The initial assumption of Lyell and other early geology pioneers was that the “Great Flood” of the Bible was not to be taken seriously, and that every geologic phenomenon in the past was like what we observe today: calm and steady and slow – like weathering.  However, in the past several generations, geologists have come to recognize that there have been short-lived, phenomenally catastrophic events that have changed the face of the landscape. One of these is the tsunami, a word of Japanese origin where it was first described scientifically. The word was chosen about a generation ago to distinguish one kind of wave event (a tsunami) from a tidal wave or a hurricane storm surge. A tidal wave is a twice-daily feature associated with Lunar and Solar cycles. In Southeast Alaska and the Bay of Fundy in eastern Canada, these can reach 15 meters in height – especially if focused into an east-west-oriented narrow bay or fjord such as at Fundy. A “tidal bore” is a wave that moves in with a rising tide, and in shallow estuaries like Turnagain Arm in Southeast Alaska, these can be walls of water several meters high – sufficient to overturn or “pitch-pole” a medium-sized boat.

Q:

What causes tsunamis? Can one happen in the US?

-Jared W

A:

There are four different kinds of events that have caused tsunamis in the past:

1.       Asteroid impacts. There are huge tsunami deposits on Haiti stemming from an asteroid impact 65 million years ago.  This was the dinosaur-era-ending Chicxulub asteroid, which impacted on what is now a small village of that name on the northern tip of the modern Yucatan peninsula of Mexico. Fragments of this explosion apparently also went sub-orbital and landed as far away as Montana and the mid-Pacific ocean. Estimates of a mega-tsunami wave in the Caribbean up to 3 kilometers in height have been suggested – enough to completely inundate a large island such as Madagascar.

2.       Landslides. The face of a mountain fell off into Lituya Bay in southern Alaska in 1958. It created a wave at least 500 meters high, judging from surrounding mountains stripped of trees to at least that elevation. Surviving witnesses describe their vessel being floated over a large raft of logs, and the modern coastline remains largely denuded. http://en.wikipedia.org/wiki/Megatsunami

3.       Volcanoes. When the volcano Krakatau exploded in 1883, 45-meter-high waves reached as far as 10 kilometers inland on Sumatra, and swept people, animals, and debris back into the Sunda Strait. More than 36,000 people died in this event, and contemporary descriptions report that a person would walk across the Sunda Strait on bodies and logs without getting their feet wet. http://www.csmonitor.com/World/Global-Issues/2010/1028/Japan-tsunami-is-small-compared-to-five-of-world-s-biggest-tsunamis/1883-Krakatoa-tsunami The tsunami from the catastrophic eruption of Thera volcano (modern Santorini in the Aegean) 3,500 years ago apparently ended the Minoan civilization on nearby Crete. The language of modern science is substantially Greek-based (with Latin) as a result of that single event.

4.       Earthquakes. In January 1700 AD, a subduction earthquake in the Cascadia region of northwestern North America sent a tsunami across the Pacific Ocean that devastated villages on the Sendai coast of Japan. The earthquake sunk a forest in Puget Sound below sea level. The wave that reached Japan was called the “Orphan Tsunami”, since it was not associated with any locally-felt earthquake or typhoon – it arrived without warning under a clear blue sky. In 1946 a subduction earthquake off the Chilean coast of South America caused what one geologist friend referred to as “unplanned urban renewal” many hours later in Hilo, Hawaii. I have personally seen signs marking the wave run-up on telephone poles 5 meters above my head in the modern downtown area. The Great Sumatra Earthquake of December 2004 killed over 250,000 people from Indonesia to India. The wave reached Sri Lanka many hours after it was initially triggered, but there was no infrastructure in place at the time to warn the millions of affected people in its path. The Great Tohoku Earthquake of 2010 triggered a tsunami that devastated northeastern Japan, directly led to a melt-down at the Fukushima Dai-Ichi nuclear plant - and destroyed docks and ships many hours later on the Oregon coast.

It is important to understand that relatively few earthquakes cause tsunamis. The basic requirement is that the causative fault must have a normal or reverse component to it - part of the seafloor must drop or lift suddenly. Modern tsunami warning systems are based on a two-tiered approach: an initial earthquake beneath an ocean floor or ocean margin is detected. If the fault system is well known (for instance is understood to be a subduction fault), then an initial warning is issued. Deep ocean buoy systems are then monitored – these waves may travel at more than 500 kilometers per hour, so they take a relatively long time to cross an ocean. If a wave-front is noted passing through this system, then warning sirens light up on the threatened coast. http://en.wikipedia.org/wiki/Tsunami_warning_system

Technically, hurricanes (Atlantic Ocean) and typhoons (Pacific Ocean) do not cause tsunamis, but they DO generate low-pressure-driven storm-surges that could top 10 meters above normal sea level in the worst cases. These are not sharp-edged waves like a tsunami, but instead are long-wavelength, very broad surges of seawater tracking the eye of the hurricane or typhoon as it hits land. Hurricane Katrina in 2005 did most of its damage with a huge storm-surge that overwhelmed the levees and barriers designed to protect New Orleans, a city that over time since its founding has sunk below sea level.

There is another class of large water waves called “Rogue” or “freak” waves. There is a long history of “disappeared” ships in the history of humankind, and anecdotal stories of waves exceeding 30 meters in amplitude that somehow left survivors. Recently, sea-height-measuring radar satellites have allowed this sort of feature to be quantified. The physics concept of constructive interference of waves comes into play, but there may also be other factors involved, including diffractive focusing and non-linear effects. For instance, the southwest-flowing Agulhas current in the western Indian Ocean has long been known to interfere with westerlies to create a zone of dangerous rogue waves of unusual frequency and intensity.  http://en.wikipedia.org/wiki/Rogue_wave

By the way: that Biblical story of the Great Flood? As scientists we must be careful and not just dismiss something out of hand - like this one was. Geologic evidence now suggests that the Black Sea was a continental basin that flooded catastrophically around 5,600 B.C.E. 

~~~~~

Get the Data. Don't get Killed

There are different risk-factors that come with different life-callings:

• Fish for King Crab in the Barents Sea: get rich fast, but unusually high risk of becoming crab food.
• Transport cocaine from Colombia to Texas: get rich fast, but unusually high risk of being beheaded.
• Fight forest fires: unusually high risk of joining the Bar-B-Que and burning with the trees. Not even health insurance until next year.
• Work as an accountant: Live Long and Prosper!

There have been several questions directed at us in Ask-a-Geologist about safety while working as a geologist or geophysicist. These increased, as expected, during the 2004-2006 eruption of Mount St Helens. To a previous question, I mentioned walking out the leading edges of moving lava flows in Hawai'i. This was not done casually, but to gain a clearer understanding of how these flows move - and why they suddenly can inundate towns like Kalapana. If we understand in a statistically reliable way how lava creates its own new topography, perhaps we can predict where the Danger Zones are. 

This has non-trivial real-world consequences: if you build in Zone 1 or Zone 2 on the Big Island, your home-owner's insurance will be phenomenally high - if you can get it at all.

In a larger sense, however, this opens the broader issue of inherent risk that comes with certain jobs - and how you can manage those risks.

In 1977 a young USGS geologist named Cynthia Dusel was part of a mapping team, surveying the Big Delta Quadrangle in east-central Alaska, when she was attacked and mauled by a bear. She survived, but lost both arms. Since then she has married, had a son, and even served as acting chief of the Western Mineral Resources team in Menlo Park, CA for a year. She's something of an icon among us in the USGS: very matter-of-fact about her disability, very upbeat, great sense of humor - and epitomizes indomitable courage. 

The response to that attack within the USGS was probably predictable: everyone going up to work in Alaska started packing huge guns. Then the scientist part in the Survey scientists woke up and many of them thought about it a bit more. Let's gather data about the real threats to geologists working in Alaska! they said. They did... and were surprised to learn that bear attacks came in as Number 7 on the list. Shooting yourself with your own weapon came in Number 3 - I once watched a rettle tech shove a cocked .357 Magnum into his holster. This led to the development of a sophisticated 3-day weapons safety training course (informally called the "Bear Blasting" class, of course) required of anyone planning to work in Alaska. The Number 2 killer of geologists working in Alaska was helicopter accidents - my first USGS boss was killed in Ketchikan harbor this way. And this led to careful "carding" of pilots and aircraft, and mandatory training of geoscientists. None of us ever worked with a pilot with less than 5,000 hours of flight experience, and we always wore NOMEX clothing and $1,500 fighter-pilot helmets, among other things.

The Number 1 killer of geologists was drowning. That's right: drowning. If you fall into deep water in Alaska (and southeast Alaska and the Aleutians are mostly islands, anyway), your arms will essentially stop working after about a minute unless you are wearing a Mustang suit. That's hypothermia for you. I came within a hairs-breadth of becoming one of those drowning statistics in Klawock in August of 1995.

It became a growing part of our evolving scientific tradition: we all loved working in the field, but it carries with it different dangers. Soooo... how can we minimize these? How can we manage these risks?

Q:

That's a pretty crazy account.  It's particularly funny to think about your work when I think of it in comparison to our OHS (occupational health and safety) officers who come around to inspect our offices periodically to make sure that our chairs are properly aligned to make sure that we don't hurt our backs by sitting all day long.  Why in the world would you be stomping around an area of jungle amidst fresh-flowing lava?  - Lisa W.

A:

Throughout my professional career I've faced many rather disparate dangers. This wasn't done for the adrenaline thrill - it's the only way in most cases to acquire the crucial data that we need to solve real world problems. In the Continental US, this usually means working in really rugged terrain. I camped overnight with a geophysical crew inside the crater of Mount St Helens in 2007. I had helicoptered in with some geophysical equipment, but after several days had to get back to the office before the end-of-week scheduled helicopter flight. A case in point: I planned for it, and walked out. However, it proved to be far more rugged terrain than I had anticipated in my planning (which was done with 10-yr-old air-photos in a terrain that is unconsolidated, and evolving nearly every day). If I had not been carrying (and using) hiking poles with my pack, I wouldn't be wearing these front teeth today. I still sustained permanent damage to my left big toe and my right knee in the ~20 km walk-out (the knee is still swollen as I write this).

In Venezuela, my personal journals have WAY too many "I was nearly killed again today" entries. That was the first time I really looked at the full array of danger that comes with working in the deep jungle. Initially we went down for a three-year assignment to map the roadless, jungle-covered southern half of Venezuela thinking the the big risk was from snakes. In fact, I encountered a Bushmaster on my very first Entrada. It took awhile to recognize the more subtle, even hidden dangers: testosterone-poisoned pilots, poorly-maintained helicopters, Chagas disease, piranha in all the rivers, etc. The Number 1 killer? The Anopheles mosquito - the vector for Plasmodium Falciparum, also known as cerebral malaria, followed closely by drunk drivers. I lost two of my best friends in Venezuela, in separate incidents, to drunk drivers.

After a series of very close calls I took the Advanced Trauma Life Support training at the University of Maryland medical school (yes, it's supposed to be for medical doctors - but I have the certificate to prove it). I discussed the issues with some more experienced field geologists and began instituting some safety protocols for the mapping mission that I was in charge of - for instance we almost never used helicopters after the first year there. We wore light-colored clothes to minimize being targeted by Africanized bees. We always walked the picas (trails) in pairs. We always insisted on mosquito nets surrounding our hammocks, etc. One of my colleagues instituted one safety protocol himself: he bailed out, breaking his contract and leaving his commitments on my shoulders. I've never begrudged him for this by the way: he was one really, really frightened dude. A year later he even left the geosciences profession, abandoning his PhD training, to become a financial advisor. Live long and prosper.

But here's the thing: you CAN control the variables, you CAN push the statistical envelope far over to the likely-to-survive side of the Gaussian probability curve. 

I took some training last year that is a case in point. You can't study a volcano unless you can get a lot of equipment up INTO it. My sons will attest that just getting 300 kilos of gear up into the Pumice Plain (the Mount St Helens Blast Zone) for their mom's Masters Degree research project was a non-trivial exercise. It's much harder to do this in the upper edifice of the volcano - so we use helicopters.

Easy to say, technically hard to do.

The safest way to ensure the survival of the helicopter and pilot is NOT to have a lot of loose shovels, antennas, and batteries INSIDE the ship. This little nugget of wisdom was culled by carefully gathering reports of all helicopter crashes in the United States over 50 years. Instead, you *sling* all that loose, sharp-edged junk. There is an electrically-controlled hook on the belly of most helicopters. We took a full day to practice this routine on a level lawn:

• Gather all your gear in a pile, weigh it piece by piece. Give that manifest to the pilot - who will do a calculation to see if he can even lift it to the elevations you will work at AND have enough margin to carry you along with it.
• Load it into a net that itself weighs 25 kg. Try to balance that net, arrange it so things tilt inward, and especially be sure that nothing is sticking out of the net that could tangle with anything - like you, or the skids.
• Then call the helicopter in to you, holding your hands up and out in the direction of the wind (we usually dangle a strip of red flagging tape so the pilot can judge the local wind velocity).
• As the ship approaches, it comes in slowly at about 1.5 meters off the ground - remember that the thing is wobbling around in the wind as the pilot tries to control it against the volcano-heat-triggered turbulence, and it is SCREAMING SO LOUDLY that you can easily get rattled just by the 140-db sound (we wear helmets with ear protection, but it's still unnerving).
• You must then walk under this shuddering, screaming thing, hook your sling net to the belly, and then carefully back out (NOT turn around), without tangling your feet in the net, and keeping your footing amid the rocks and talus.
• Above all, if you stumble, you must NOT grab one of the skids to regain your balance. If you do, the ultra-light craft will flip, the blades will hit the ground, and all that angular momentum must go somewhere really, really fast – and you will both probably die. You have to trust the pilot, and he must trust you: if you hook the net wrong, or inadvertently tangle it in one of his skids, it could kill him. The craft is so fragile that you can literally push it around in the air above you with your hand... but those screaming turbines mean it is powered by 600 horses. Everything spinning is so finely balanced that if a blade nicks a branch it will chip a chunk off – and it then becomes hugely unbalanced. Then the angular momentum comes into play, and the aircraft will literally beat itself (and its occupants, and everyone within 20 meters) to death.

When a helicopter goes down, that's just the beginning of the bad stuff... think of the old high-school joke: What's red and green and goes round and round real fast? A frog in a blender. Now imagine doing this sling exercise on a steep ridge with 30-knot wind gusts.  THAT's why we practice and practice all day long on a lawn to do this right. So it's reflex. So when the brain starts mis-firing, you STILL do the right things.

This is basically how I teach Jujitsu to my students, by the way. No one ever defended themselves from their Worst Nightmare by using their cerebral cortex - it only works from muscle memory: reflex.

Live Long and Prosper. And still enjoy the Adventure!

~~~~~

Water and Specific Heat Capacity

It's not a coincidence that about 80% of the human population lives within 60 miles/100 kilometers of an ocean margin. Spend a winter (or a summer) in an interior state like Kansas, or Kazakhstan, and you will understand why they are not crowded. Temperatures in Fairbanks, Alaska, can range from 86F/30C to below -60F/-50C between Summer and Winter - and that's above the Arctic Circle! I've personally experienced temperatures of 130F/50C in Arizona and 142F/61C while working in the interior of Saudi Arabia.

We would have occasional snows (and freeze rain) when we lived in Virginia. That wasn't so bad... But sometimes we do not even see snow during the winter in Vancouver, and it's notable when the temperatures get much above 75F/24C.

I could easily get used to this. I think I'll stay...

There's a downside to this, of course (there always is, isn't there?). Populations close to a seashore are much more vulnerable to a tsunami from a seafloor fault rupture - or an asteroid impact in the ocean. Volcanoes can even figure into the Coast is Toast picture: the tsunami that resulted from the explosion of Krakatau in 1883 traveled more than 10 kilometers inland onto neighboring Java and Sumatra islands... then swept everything it had picked up and took it all back out to sea. Contemporary accounts mention being able to walk across the Sunda Strait on logs and bodies without getting your feet wet.

There is a reason for that very human tendency to hug the coast, and it's not for the sandburgers and grit-flavored potato salad. It's because of the moderating effect of nearby oceans. The key to that effect is the specific heat capacity of water - it is more than 4 times greater than air. In other words, it takes more than four times as much energy to increase a unit mass of water by one degree C than it does to raise the same mass of air by one degree. That means that the oceans act like a thermal buffer - because they can absorb and release so much heat without much of a temperature change.

Bottom line: ocean temperatures don't change much.

We notice the effects of water on temperature in a number of different ways, and the next series of questions raises an unusual issue:

Q:
Does an object traveling under water get colder as it increases it speed through the water? Similar to a wind chill factor. 
- Gaylord M.

A:

Yes - if the water is colder than the object moving through it.

Water has a specific heat capacity of 4.2 with respect to air. This means it can hold - and transfer - far more energy than air for just one degree of raised or lowered temperature. The faster you move through a medium (like water) that has a different temperature, the faster and more effective is the thermal exchange, all other variables being constant.

Most people know that getting into cold water will chill them much faster than walking through air of the same temperature. I noticed when I lived near the Red Sea that if I went diving in temperatures below 82F/28C, that I would quickly become hypothermic. This hugely different heat capacity is also why it is so important to wear clothing that keeps moisture away from your skin as much as possible.

Q: 

Thanks for the reply. I asked the question, as I was wondering if it could have had an effect on the Titanic's rivets to cause them to fail. I had watched a segment on the History channel where they had ran some tests and determined the rivets had not failed. However they were running their tests in what appeared to be a normal environment. Only one of the test rivets failed.


A: 

The possible effect of ice-temperatures on the Titanic's rivets is an interesting thought. I'm not a metallurgist, but have watched, with interest, several back-and-forths in the semi-scientific literature about the possible "failing Titanic rivets" issue.

In this case I don't think the temperature would have made much difference, because North Atlantic water ranges between 0C and 22C, depending on the month.

That's not really much of a temperature difference, considering the temperature that the rivets were forged at, and the fact that the ocean temperature cannot go below the freezing point of ice. Because of water's large specific heat capacity, there really is not much of a temperature change in the North Atlantic.

There were literally thousands of steel-riveted ships plying the North Atlantic during that epoch, and it makes more sense to worry about metal impurities in a given production batch of rivets than in the narrow temperature range that they would operate under.

~~~~~

Infrasound

The Earth really is a living thing in many senses of the word. For instance, it is very active – it even makes sounds.

Q:
Hi, Wondering what kind of sounds the inner earth makes? Do you know where I might go to hear this?
Thank you 
-Nathan W.

A:
There are sounds from the "inner Earth", but they are generally at frequencies below what the human ear can detect - this frequency range is called "infrasonic". Occasionally these can be heard, but not normally.

I once heard a recording from a seismometer located on Tungurahua volcano in Ecuador - but it had been electronically speeded up about 400 times to bring the signal up into the audible range. It sounded like a large animal moaning and roaring. This of course would be normally inaudible to the human ear.

Here is one somewhat different, for volcanic gas venting: http://volcano.oregonstate.edu/vwdocs/videos/siocomm.mov 

Here is an example of the sounds of an actual surface eruption at Tungurahua: http://en.rian.ru/video/20101202/161596301.html

Note that if the volcano is not actually erupting at the surface, the sounds made are almost always inaudible (infrasonic).

More volcano sounds can be heard here: http://volcano.oregonstate.edu/book/export/html/385

In some volcanoes there is a seismic signal detected called "harmonic tremor" - it is generally thought to be caused by fluid movement through conduits deep below the volcano, and sometimes is a portent of an impending eruption (Mt Pinatubo in the Philippines in 1992, for instance). Harmonic tremor is typically in the 2 Hz frequency range - well below the lowest frequency that a human ear can detect (which is about 20 Hz).

Earthquakes (shifting, sliding crustal plates) also generate seismic waves, but like those under a volcano they tend to be mostly at frequencies well below what a human ear can readily detect.

~~~~~

Geoengineering

Geoengineering is a very broad topic – in fact, no one group of people can actually agree what the word actually encompasses. One thing for sure, however: the word carries with it a lot of emotion already, not unlike Fracking.

Q: What is geoengineering and why do people say it is bad?

- Byron S.

A:

The term “geoengineering” (or environmental engineering, depending on who you are listening to) can encompass a lot of very different things: 

• Stratospheric Particle Injection for Climate Engineering (SPICE). This experiment this Spring in the Europe envisioned injecting water into the atmosphere at a 1-kilometer altitude. However, there have been proposals to inject vast quantities of sulfates into the stratosphere to reduce global warming. The theory underlying these is that Mt Pinatubo already did this in 1993 – and lowered the Earth’s average temperature by more than a degree C for two years.
• Injecting large volumes of iron sulfates into the Southern Ocean in 2009. This was done to test a theory that adding iron to the ocean would encourage phytoplankton growth, leading to an increase in zooplankton growth with concomitant oxygen release and carbon dioxide sequestration all at the same time. The fear, of course, was that the exercise would trigger a massive, toxic algal bloom.
• Injecting water from a hose maintained at a 1-kilometer altitude to test if this could cause more reflectance of solar radiation, and thereby reduce global warming effects.
• All the Walmart parking lots in the world contribute to large-scale diversion of water from the Earth and unusual absorption of solar radiation, creating unnatural microclimates (“heat islands”) that will affect local and even regional weather. In fact, one can watch any local regional weather radar, and readily see that clouds will often form donut holes over large, paved metro areas like Portland, OR.
• Groundwater depletion and other anthropogenic (man made) changes in terrestrial water usage were responsible for about 42% of the 8-cm rise in global sea level observed between 1961 and 2003.
• Ethinyl Estradiol (EE2) is the active ingredient in birth-control pills. More than 100 million women worldwide use contraceptive pills, and the products make their way through waste-water treatment systems into rivers and lakes, where they have caused widespread disruption of aquatic environments. It has done this by disrupting endocrine systems in wildlife (for example, irreversible development of eggs in the testes of male fish, a condition called “intersex”). EE2 introduced into a Canadian lake in 2001, at a level of only 5 parts per trillion, caused the population of one fish species to completely collapse.

There are other potential kinds of geoengineering, limited only by the creativity of people who worry about the Earth we live on - and who DON’T worry about where funding for their proposals might possibly come from.

These mega-scale engineering changes all sound like good ideas – they promise potentially great (and highly leveraged) rewards. The problem with geoengineering, according to a lot of people, is that if we play with our ecosystem on broad scales like these, we can never be sure of the consequences.  We may very well, with the best of intentions, create a spiraling-out-of-control disaster. We could just be asking for it.

An extreme example of this fear was the concern that when the Large Hadron Collider in Europe went online, its huge particle beams would create a tiny Black Hole - that would burrow to the center of the Earth and destroy our planet from inside out. The most compelling argument against this, of course, is that far greater particle energies are generated daily in our upper stratosphere by cosmic rays… without any noticeable harm having been done over the past 4.5 billion years or so.

Another example of mega-scale engineering is the massive use of DDT to solve a perceived insect problem – to save crops and mitigate human disease by eliminating dangerous insect vectors. We now know, of course, that the extensive use of DDT did solve, at least temporarily, some crop and human disease problems. However, it had huge unforeseen downrange consequences like plummeting bird populations and possible birth defects.

Some people might call the massive use of antibiotics another example of a well-intended global effort to deal with a human problem – but one that has in fact led to a growing disaster. We now see explosive growth of Multiply-Resistant Staphylococcus Aureus (MRSA, or the terrifying “flesh-eating bacteria” increasingly in the news). Indiscriminate antibiotic use has also led to a world-wide resurrection of resistant tuberculosis, Bubonic Plague, and other once-curable diseases.

Perhaps even more terrifying is the research into genetic engineering: what if something unforeseen gets loose into the world’s environment, with disastrous and irreversible consequences, like Zebra Mussels, lampreys, and Asian Carp getting into the Great Lakes? Or Kudzu being introduced into the southeastern US? Or Africanized bees introduced into the Western Hemisphere? Or cases of incurable cerebral malaria exploding in areas where unregulated hydraulic mining is rampant?

In 2010, a gathering in Oxford, UK, came up with some guiding principles for geoengineering:

-          Geoengineering should be regulated as a public good

-          There should be public participation in decision-making

-          Research should be openly published

-          There should be independent assessments of potential impacts

-          Decisions to deploy any new technology should be managed within a “robust governance framework.”

All of these principles sound great – but are terminally vague. Furthermore, they will probably never be implemented on an international scale. It takes just one nation ignoring the International guidelines on something as far-reaching (and frontier-crossing) as geoengineering to abrogate the whole effort for the rest of the international community.

If there is a lesson here from the pesticides, antibiotics, and biological introductions, it is that nothing is consequence-free. However, many people feel that they are forced to just stand by and helplessly watch things unfold - decisions made by just a few people. That may be why there are such vociferous demonstrations to something as innocuous-sounding as SPICE.

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Black Holes & Supernovas & Geology

Here is a continuing question from 3-yr-old Samantha. It actually goes to the heart of why we have geology in the first place: black holes and supernovas of earlier suns have led to a cyclic mix of fusion-created heavy element products like oxygen, carbon, iron, and silicon - major constituents of our rocky Blue Marble, water-covered planet. A world like ours could not have existed in the early life of the universe.


Q:
Thank you so much for your reply. She (Samantha) still talks about you from time to time. Then out of the blue she asks "Mommy, what are black holes made of?" I don't know! :)
--Jo L.

A:
Well, the short answer is a LOT of mass. There are actually at least two different kinds of Black Holes.

A Stellar Black Hole starts with the collapse of a very large star - a star much bigger than our Sun. As the star uses up its hydrogen by fusing it to helium, it starts converting helium to carbon - these stars are a deep red, almost garnet color in a visible light telescope. Rather quickly on a cosmic time-scale, it will start converting carbon and helium into a number of other life-critical elements, all the way up to iron. The fact that the Earth's crust contains elements up into the uranium range suggests other processes, too. All the material we find on our own Earth has come from this thermonuclear process - probably from many ancient stars that reached old age and blew up long ago.

In two words, we are “Star Stuff.”

Somewhere in this winding-down process for this very large, earlier star, there is an initial collapse of the outer blanket of hot gas material down to the star's core, and a "bounce" causing an initial huge blow-out of the outer envelope. This is called a nova, or in some cases a super nova. It produces prodigious, short-lived amounts of radiation from visible light all the to X-Ray energies and beyond. In a distant galaxy, a supernova can look temporarily like a nearby star in our own galaxy.

This outer shell ejection process creates something called a Planetary Nebula - a glowing shell of gas that almost looks like a planet in a cheap telescope. Finally, there is a huge terminal collapse and all the remaining matter, without thermonuclear heat to hold it up, collapses into what becomes a Black Hole. It's called a Black Hole because there is so much mass in such a tiny volume that it bends light. It bends light so strongly - this is an essential part of Einstein's General Theory of Relativity - that light can't get out of a certain volume outside the central concentrated mass. This "edge" where light can't escape from is called the Schwarzschild radius, or the Schwarzschild discontinuity. You can guess who suggested this idea first. If the original star isn't big enough, the mass will collapse back into a White Dwarf - or if there is more mass, it will collapse into a neutron star, a teaspoons of which would weigh tons on Earth (if you could get it here or even weight it).

This is a description of a multi-stellar-mass Black Hole. 

There are other, far larger Black Holes. Galactic Core Black Holes are found in the centers of most galaxies including our own – and they form for different reasons and are HUGE. These Black Holes result from too many large stars in the crowded center of the galaxy being in too small a confining space - and they coalesce into each other forming a Black Hole that grows ever larger with time as it gobbles other nearby stars spiraling into it from tidal orbital collapse. In some science fiction books this is called "The Eater" or the Black Monster. We know there is a Galactic Core Black Hole in the Sagittarius constellation - the center of the Milky Way galaxy - because astrophysicists can see huge Doppler shifts in radiated light over a very small angular separation in a tiny area. This zone was originally named "Sagittarius A" - for the first apparent brightest star classified in that constellation by early astronomers. Sensitive satellite detectors indicate that the center of this interesting area radiates light all the way up into the X-Ray range of energies. On one side the Doppler shift indicates that material is rotating TOWARDS us (the absorption bands are blue-shifted), and close by on the other side there is a red shift telling us that it is rotating AWAY from us. The latest indirect calculations suggest this area, called Sagittarius-A* (Sagittarius-A-Star, or "Sgr-A*" for short) is about the diameter of Mercury's orbit around our Sun - but holds a mass equivalent to at least 44 million Suns in that relatively tiny volume. It's hard to see this, as the whole mess is about 26,000 light years away from us, so it's taken some very clever astrometrics by some very smart astrophysicists to get these numbers.

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This seems like more than a normal 3-yr-old might be able to absorb. I am struck, however, that this 3-yr-old of yours has such a wide-ranging interest in scientific things. She could not get there without a highly supportive parent who will spend the time at least trying to answer her questions. You must have some rather eclectic conversations with your daughter.

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