Monday, January 30, 2012

Accretionary Wedge #42: Countertop Geology

This time around it's volcanoclast sending out the call for posts for this round of the Accretionary Wedge, asking geobloggers about countertop geology.  Because pretty much everyone knows that the best countertops in a kitchen or bathroom are made of granite... or are they?

Although natural stone as countertop or tile is sold as either "granite" or "marble", they are often neither of those.  The divisions "granite" and "marble" generally mean two kinds, the first being hard countertops made of silicate minerals and softer ones made of carbonate minerals.  The term 'granite' is applied very loosely!

And that's the case with mine.  A few years ago, my wife and I bought a house and the kitchen needed a total gutting.  So before we moved in, we spent about a month tearing out the old kitchen and building the new one.  While searching for something to use as a countertop, we came across a pile of "granite" tiles that I HAD TO HAVE.  The stone was a black & white gneiss, a metamorphic rock.  They were on a deep discount so we took home enough to cover the area we had planned for the counter.  I then got to cut the tiles with a tile saw to fit, glued them down to the base we had built, and filled it in with grout.  Cutting the stone tiles was good fun, of course!

The gneiss had large white feldspar clasts and tiny little folds in the foliation, and consequently was loaded with shear sense indicators - and yes, I did have them all going the same direction  :-).  I had my students in structural geology over a time or two for "lab" where they had to find & sketch some of them... and then we made home-made ice cream... you know, for the thermodynamics lesson about enthalpy with mixtures of ice & halite, or something...

We sold that house and moved to another a couple years back, and unfortunately we lost a lot of pictures that I had taken of the countertop.  But, fortunately, some of the pictures of the kids had been backed-up, and I managed to find one of B that shows the countertop in the background.  So if you can manage to look past this adorable blue-eyed blondie who doesn't have all her teeth yet, you'll see the gneiss in the background.

And here's a cropped, zoomed in version.

Saturday, January 14, 2012

Teaching About Climate Change, Part 1: Framing the Discussion

Every year, I teach a geoscience course on natural resources & the environment.  It is a general education course that any student can take so long as they've already taken a college science course.  Students come in from a wide variety of backgrounds & interests.  I've had students who are majoring in elementary education, engineering, business, math, geology, chemistry, geography, sociology, exercise science, and many others.  I love teaching this course.

One of the biggest challenges, however, is teaching the subject of climate change.  This subject is so big, broad, integrated, and so complex that it is probably the most difficult subject to teach in the geosciences in my opinion.  Further, the subject isn't just about science, because the issue has become such a hot topic in our society.  Another challenge here in my case is that I'm not a climate scientist in terms of area of specialization.  As a geochemist I can easily relate to a lot of the chemical data in climate science, but my expertise lies in other fields.  These challenges mean that a careful, thoughtful approach to teaching the subject is all the more necessary.

So I'd like to talk about how I teach this subject in the hopes of hearing from others who also teach it.  I plan to share a couple of posts on the topic.  In this first one, I'd like to talk about how I frame the discussion.  I think there is nothing more important than this when teaching a controversial subject.  I pose this in my course as "Asking the right questions about climate change", with four questions:
1) Is the Earth's mean annual surface temperature rising?
2) If so, what is the cause?
3) If so, what effects will it have?
4) What should be done about it?
The first three questions are science questions; they can be answered by data.  The first three questions also gradually increase in uncertainty.  The first question brings with it the least amount of uncertainty because it is the least complex.  It simply involves measuring the same thing, over and over again, in different ways and over long periods of time, and then seeing what the trends are in the data.  The answer to the first question is obviously "yes", since the rest would be moot otherwise.  The second question brings more uncertainty, since it is looking for a cause.  Causation is, as any scientist knows, often difficult to prove.  Often we look for correlations that have strong theoretical reasons to indicate causation, but there is always uncertainty in this.  The third question brings even more uncertainty, because it brings an added dimension of prediction of the future.  Creating models that will correctly predict the future is hard work!  Especially in this field, where the models have so many variables and feedback loops.  But there is good, rational uncertainty, and then there are the smear campaigns that attempt to insert uncertainty into places where it really doesn't exist.

The fourth question is not a question that can be answered by science alone.  Science can and should inform decisions here, and it does so by clearly answering the first three questions.  But this last question is broader than the natural sciences.  That tricky word "should" in question four brings the trouble.  How we answer this last question depends also on perspectives from economics, cost/benefit analysis, morals/values, public policy, political theory, social science, behavioral science, and other fields.  The question cannot be answered by natural science alone, and I think it intellectually prudent to be upfront about this.

I think this framework allows students to begin to separate the science from the politics in their minds, and they need to do that in order to understand the issues.  In our culture, complex issues often get boiled down to bite-sized bumper sticker position statements, and people are generally divided into two general camps - the pros and the cons.  That is, the science and the politics get conflated, and before students can begin to think clearly about the issue and come to an informed opinion, the science and politics need to be distinguished as separate entities in our minds.  I think the absolute wrong question is "are you for or against global warming?"  That's just too vague & too convoluted to be useful in education.

So that's how I approach it.  How do others who teach this subject frame it?

Monday, January 9, 2012

Accretionary Wedge #41: Most Memorable Geologic Event I've Directly Experienced: The Eruption of Mt. St. Helens

In the latest call for posts for the Accretionary Wedge, Ron Schott asked geoscience bloggers to relate "the story of the most memorable or significant geologic event that you've directly experienced".

For me that's easy, and yet also difficult.  Easy because there's really only one significant geologic event that I've directly experienced that I'd call memorable & significant, but difficult because I had just turned 6 years old and don't recall a lot of it.  

On the 18th day of the month of May, 1980, the lower 48 states of the U.S. experienced the eruption of Mt. St. Helens.  Obviously when the mountain starts shakin' in a serious way, you don't live to tell about it from up close.  Over 50 people died from the eruption, including one USGS geologist David Johnston who was monitoring the volcano at the time.  He sent word via radio just as the eruption began "This is it!", and gave his life in the study of this mountain.  I lived about 100 miles north of the volcano in a small town called Bremerton, WA.  I don't recall a whole lot about the event, but I do remember watching some of the news reports on TV.  Reports showed video of the ash-clogged & log-jammed streams, snow plows being used to remove the ash from roads, and pictures of entire forests flattened in one direction like matchsticks.  It was amazing.

The mountain had been building up prior to this, with a large bulge on the north flank.  The catastrophic blast of the mountain that day occurred after the bulge over-steepened the hillside and a huge landslide removed material down the mountain, lowering the pressure on the magma below and releasing the main blast.  The blast mainly came out of one side of the summit, the north face of the mountain.

The ash therefore mainly blew northward, but it didn't reach Bremerton.  Instead, the winds took it eastward.  So we never saw any ash where I lived, but one day after the blast my dad decided to drive south.  He collected a small bottle of the ash, which has sat on my shelf for a number of years now and is pictured in these two photographs.

The experiences of geologists from the USGS and the University of Washington monitoring the mountain at the time are documented very well in a CNN video on youtube that unfortunately I can't embed here, but here's the link:  The video is about 7 minutes long and well worth viewing to get a bigger idea of the impact of this eruption.  Also for more info on the blast itself, check out this USGS eruption fact sheet.