Teaching evolution in a geology class...

Every spring, I teach a laboratory course on Historical Geology. It has a prerequisite of a lab course in Physical Geology (taught in the fall) and together they provide the student with a solid foundation for being a geology major and taking upper-level undergraduate courses in the field (e.g. mineralogy, petrology, structural geology, paleontology, stratigraphy-sedimentation, etc).

Historical Geology is not the history of geology (although that is partially covered) but the history of the Earth and, relating to the topic of this post, the origin and evolution of life on Earth (which is, of course, preserved in the geologic record).  While not a biologist, I do teach about biological evolution since it's completely impossible to discuss fossils and the history of life without that framework.

This does present challenges in my class for three reasons.  First, I teach at a rural community college and a number of my students are skeptical of evolution (I've even run into some young-Earth creationists).  Second, most of my students have not studied biology at the college level, only in high school, and we now know from recent studies that many high school teachers cover evolutionary theory in a minimal way, if at all.  And, third, I only have one class period to discuss evolution by itself (hey, it's hard to cover 4.5 billion years of geologic history in one semester!).

So how do I approach teaching evolution?  The textbook I use (The Earth Through Time) has a section on evolution which students are required to read but I start my lecture  by introducing The Origin of Species.  I put up a slide showing the table of contents and summarize the contents of each chapter leading students through Darwin's original arguments.

In Chapter 1, Variation Under Domestication, Darwin gives examples of variation artificially introduced via selective breeding.  He spends a lot of time talking about pigeons since fancy pigeon breeding was a popular pastime in 19th century England.  Darwin argued that laws of heredity (even though he had no understanding of DNA, etc) and artificial selection by human breeders creates these varieties.  Nobody in my class finds this controversial since we all can see variation under domestication in our everyday lives (e.g. dog breeds).  If I stopped there, some might argue by analogy that this is evidence for Intelligent Design.  But let's continue...

In Chapter 2, Variation Under Nature,  Darwin discusses examples of variation in animals and plants in nature.  Anyone who has tried to use a field guide to identify birds or flowers out in the real world knows that there is some degree of natural variation among animals or plants of the same species.  Darwin notes that it's often hard to distinguish separate species from variations within a species and concluding that the amount of difference between species must be greater than the amount of difference between varieties within a species.  All of these natural variations among organisms, Darwin implies, is evidence against the special creation of discreet species.

In Chapter 3, Struggle for Existence, Darwin starts to gets to the heart of his argument and talks about the struggle for existence, referencing the work of British economist Robert Malthus (1766-1834).  Nature, as poet Alfred, Lord Tennyson wrote in 1850, is "red in tooth and claw."  There is a finite amount of resources (food, mates, living space) and living things must compete for there.

In Chapter 4, Natural Selection, we get to the concept of survival of the fittest.  If we acknowledge that there's variation among organisms of the same species in nature, and we acknowledge that there's a struggle for existence, we can see that some variations may be beneficial to the survival (and mating opportunities) for the organism while other variations may be harmful.  Beneficial adaptations are successfully passed on and over time this will lead to change. 

That's basically all biological evolution is - genetic change over time.  It's a fact, something we can measure and quantify.  One commonly used definition for evolution is that it's any change in the frequency of alleles (alternative forms of a gene) within a gene pool from one generation to the next.  Darwin saw this change as slow and gradual (today called phyletic gradualism) but there's pretty good evidence today from the fossil record that evolutionary change can occur rapidly (geologically rapid, not rapid in terms of an organism's life span).

In Chapter 5, Laws of Variation, Darwin attempts to explain how laws of heredity work and mostly gets it wrong.  It's hard to fault him, however, since it took another 100 years before we really started understanding (and still don't fully understand) and genetics and DNA really work.  That's why modern evolutionary theory is sometimes referred to as NeoDarwinism, it's Darwin's ideas with the addition of modern genetics.  Darwin's theory of evolution was strengthened considerably by what we've learned in modern biology.

In Chapter 6, Difficulties on Theory, Darwin shows why what he did is science and not pseudoscience.  He acknowledged that there were difficulties with his ideas (in 1859, mind you, that doesn't mean they are still difficulties today!).  Darwin admits he has a hard time, for example, explaining the evolutionary development of the eye.  He then proceeds, however, to outline a plausible evolutionary scenario, one which modern biologists have refined only slightly through new discoveries.

Chapter 7, Instinct, is basically additional material on natural selection and Chapter 8, Hybridism, discusses hybrid animals, like the mule, and how they affect his theory.  This chapter suffers from Darwin's lack of knowledge of modern genetics (again, perfectly understandable).

Chapter 9, On the Imperfection of the Geological Record, discusses the fact that the fossil record is imperfect - only an incredibly small percentage of organisms become fossilized.  This is used to explain why we don't see a complete succession of intermediary forms for everything.  This is only partly correct, however, as more modern discoveries have shown.  Evolutionary change is probably not completely slow and gradual and in many cases may be represented by long periods of stasis punctuated by geologically rapid change.  In addition, Darwin knew nothing of such things like Precambrian fossils while today we have many examples of metazoans (multicellular life) prior to the Cambrian explosion as well as examples of prokaryotes (bacteria) extending back to over 3 billion years ago.

In Chapter 10, On The Geological Succession of Organic Beings, Darwin discusses natural selection some more as it relates to the fossil record and talks about extinction.  Many of the areas Darwin admitted to having difficulties understanding are no longer problems with our increased knowledge of the fossil record and modern genetics.

In Chapter 11, Geographical Distribution, and Chapter 12, Geographical Distribution continued, Darwin discussed the importance of geographical changes, like the isolation imposed by island environments, on natural selection and speciation.  Here he was heavily influenced by his earlier work in the Galapagos Islands.

In Chapter 13, Mutual Affinities of Organic Beings: Morphology: Embryology: Rudimentary Organs, Darwin links existing taxonomic classification schemes with his theory of common descent with modification.  In other words, organisms are classified into phyla, classes, orders, families, genera, and species on the basis of shared characteristics and these are evidence of biological evolution.  He also discusses imperfections in organisms which is an argument against any intelligent design (a designer would have done a much better job, not just kludged together existing systems seen in more "primitive" organisms).

Chapter 14, Recapitulation and Conclusion, wraps it up:

"There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and wonderful have been, and are being, evolved."

After working through the book, students see that it's not really very controversial at all (unless their minds are already closed based on their belief in a specific interpretation of Scripture).  I then move into an introduction to DNA and genetics and show how this knowledge has only strengthened Darwin's theory of evolution.  I also encourage students to actually read The Origin of Species.

We also spend a lot of time looking at rocks and fossils in both the lab and in the field throughout the semester and it's hard not to believe in evolution after seeing it with your own eyes!

Let's go hiking

It's Hua Shan (Mount Hua) in Shaanxi Province of China.  It's a sacred mountain in Taoism and the site of several temples.  Looks like a fun hike!

The Raven's Gift

Just finished reading The Raven's Gift: A Scientist, a Shaman, and Their Remarkable Journey Through the Siberian Wilderness by Jon Turk (2010, St. Martin's Press).

Jon Turk has a PhD in organic chemistry from the University of Colorado (hence "scientist" in the title) but seems to have worked most of his professional life as a environmental and geoscience textbook author.  His great love is adventure travel and he's kayaked the North Pacific, biked through the Gobi, rock climbed on Baffin Island, and, of course, traveled in the Siberian wilderness (Kamchatka Peninsula area) among other things.

I picked up this book for two reasons - first, as I've mentioned in a previous post, I like reading books about travel to exotic locales I'll likely never see.  Second, never mentioned before in this blog, is that I have had an interest in shamansim stretching for many years (I think it started many, many years ago when, as a young college student, I took a class called Psychology of Consciousness with Dr. Stephen Larson, author of The Shaman's Doorway: Opening Imagination to Power and Myth).

While kayaking the coast of the Kamchatka Peninsula in 2000, Turk met some Koryak people, natives of the Siberian coast, and an elderly female shaman named Moolynaut.  Turk had been suffering from chronic pain from a broken pelvis due to being caught up in an avalanche while skiing.  Moolynaut heals him by appealing to Kutcha, the Raven Spirit.  Over the next decade, Turk makes several trips back to Kamchatka to meet with his Koryak friends and Moolynaut.  He was also given psychotropic mushrooms (Amanita muscaria) - a traditional shamanistic practice in Siberia.

The book is intensely personal, sometimes uncomfortably so, and large parts of it are about Turk coming to terms with the untimely death of his wife in a second avalanche accident.  We learn about the sad demise of a way of life for the Koryak, traditional reindeer herders, who, like many indigenous people around the world, were decimated by the dominant culture (in this case the Russians).   The descriptions of the tundra landscape in Kamchatka are interesting.

I have to confess some disappointment with the book, however.  While well-written and holding my interest, there was very little in it of shamanism, per se.  Turk's experiences with Moolynaut are short and almost perfunctory.  Almost nothing is given about the Kolyat's beliefs or Kutcha, the Raven.  I would have liked to learn more about the Koryak's shamanistic beliefs.  Also, while Turk talks in the book of taking photographs, none are given in the book. Despite these criticisms, it still is a worthwhile read.

Imminent eruption of Yellowstone?

No.

Volcanologist Erik Klemetti over at the Eruptions blog (which I have permanently liked in the sidebar), has a great post on Yellowstone: The public and media obsession with the caldera where he discusses a December 2010 paper by Chang, et al. in Geophysical Research Letters titled An extraordinary episode of Yellowstone caldera uplift, 2004–2010, from GPS and InSAR observations and then provides some examples of the media morphing this into some kind of doomsday scenario.

The paper, of course, makes no such claims and it's mostly baseless hysteria by journalists who, as is typical, neglect to seek any expert advice on a subject they obviously know nothing about.  Either that or they're cynical liars.  Whichever it is, it reflects poorly on their profession (What Do Politicians, Used Car Salesmen, and Journalists All Have in Common?)

Students won't like this...

Interesting article from the New York Times a few days ago titled To Really Learn, Quit Studying and Take a Test.  Research shows that you'll be able to recall 50% more information after a week if you're tested on the material as opposed to simply studying or doing concept mapping (another educational fad in vogue right now).

The study, "Retrieval Practice Produces More Learning than Elaborative Studying with Concept Mapping" was recently published by Jeffrey Karpicke of Purdue University and graduate student Janell Blunt in the journal Science.  Looks pretty compelling.  I can't imagine, however, that my students would appreciate tests every week to help them learn the material.

Remedial Courses

At the community college where I teach, some interesting statistics were released recently.

· Percent of new matriculated students in one or more remedial classes in 2008 = 51%
· Percent of new matriculated students in one or more remedial classes in 2009 = 55%
· Percent of new matriculated students in one or more remedial classes in 2010 = 58%

Oh my.  We haven't changed our English and math placement tests over the past few years - this looks like a real trend.

While we pretend these are students not performing at the college level, in reality, many of these students aren't even performing at the high school level - some of these students need remedial instruction in arithmetic, reading, and writing coherent sentences (why they were given a high school diploma is beyond me but I suspect that showing up and breathing are the main requirements these days).

We're not unique, all community colleges have to deal with this.  Aren't you glad your public school taxes go toward graduating students who then use up state and federal financial aid to take remedial courses in college?

Are those supplements doing anything?

Like most people my age, I take a variety of dietary supplements (in my case, they include a men's multivitamin, extra vitamin D, and fish oil).

The very neat Information is Beautiful website has a interesting graphic illustrating the Scientific Evidence for Popular Dietary Supplements.  A lot of claims are made about many supplements, but in some cases, scientific evidence for those claims is sorely lacking.  You can dig into the data used to generate this image by following links at the bottom of the page.

I do like green tea (I should drink more of it) and see that cocoa looks pretty good (I suppose I could manage to choke down a little more dark chocolate for purely medicinal reasons).

Richard Fortey Trilobite Lecture

Dr. Richard Fortey FRS (FRS means Fellow of the Royal Society) is a British paleontologist and trilobite expert at the Natural History Museum in London.

He is the author of a number of books including Earth: An Intimate History, Life: A Natural History of the First Four Billion Years of Life on Earth, and Trilobite: Eyewitness to Evolution, among others.  All are excellent and very readable.

Here, Fortey gives a 55 minute lecture on trilobites for the Oxford University Museum of Natural History 150th anniversary lecture series.  If you like trilobites, it's a worthwhile way to spend an hour.

Random Acts of Kindness

Maybe some people (pretty girls, for example) are used to strangers being nice to them, as a middle-aged, relatively unattractive, introverted male, I'm not.

Friday night I was off to visit with some friends and had to stop at the ATM since I had absolutely no cash on me (I was waiting until payday to get some).  I stop at a kiosk in the town of New Paltz that has two cash machines and someone else is using the other one.  Put my card in, enter my PIN, and I get the message "Incorrect PIN".  I do it again.  Same message.  Then I begin the doubt myself (I'm getting old, maybe senility is setting in) and try a couple of other combinations.  Then I call my wife on the cell phone and ask her what the PIN is.  She gives me the same number I originally tried.  Try again and still doesn't work.

I complain to her that I need to have $1.00 to get over the bridge (Mid-Hudson Bridge as my friends are in Poughkeepsie) and I don't have it.  I'm 20 minutes away from home so it would be a 40 minute round trip to return and get a buck (and cost more than that in gas!) and I'm already worried I'll be late.  I tell her I'll go in the car and see if I can scare up some change in the glove box, under the seat, whatever.

As I'm in the car looking for change (managed to find only about 60 cents or so), the guy who was at the other ATM comes over to my car window.  At first I get a little nervous since it's dark out and all but I roll down the window and he says "I overheard you talking on the phone and I wanted to give you a dollar so you can pay the bridge toll."  At first I didn't want to take it, I'd never ask a stranger for money, but he insisted so I thanked him and we parted ways.

I'm usually a very cynical person, typically believing the worst in people (first thought when someone approaches my car window at night - they want to rob me or beg for money) and I'm not often disappointed.  This genuinely surpised me.  There are kind and thoughtful people in the world (and I'm ashamed to say I'm not usually one of them).  Now I know it's a small thing, it's not like I was hungry or stranded somewhere or beset with poverty, just inconvenienced and annoyed, but it was still a nice gesture from one stranger to another.

Since I don't know who the person was, I'll pay him back by trying to do something nice for a stranger myself (now don't send me email asking for money, it was only a dollar!  By the way, have you heard what the difference is between a community college professor and a pizza?  A pizza can feed a family of four).

That button above - "Practice random acts of kindness and senseless beauty" refers to a quote from author Anne Herbert that has inspired many people.  See, for example, the website for the Random Acts of Kindness organization.  Random acts of kindness week is February 14-20.  I resolve to try to do at least one nice thing a week for someone, even if it's just an encouraging word.  Can't be too hard to do, can it?

Volcanoes in Kamchatka II

In yesterday's post (Volcanoes in Kamchatka I), I discussed the reason why there are volcanoes on the Kamchatka Peninsula (subduction of seafloor crust from the Pacific and North American Plates under the Kamchatka Peninsula which is on the Okhotsk Plate).

Today, I wanted to say a few words about the image above taken by the Terra satellite last October.  Click here to embiggen and see a lot of neat details.  The location of this image on the Kamchatka Peninsula is shown below.  That little island on the lower-right edge of the image is Attu, the westernmost point of the Aleutian Islands coming off Alaska.

As you can see from the image I showed yesterday, these volcanoes are located near that triple junction between the North American, Pacific, and Okhotsk tectonic plates.

By the way, see those islands coming southward off Kamchatka toward Hokkaido Island in the north of Japan?  Those are the Kuril Islands and just today (January 22 at 1247 UTC) they experienced a 4.7 magnitude earthquake due to the constant subduction of the Pacific Plate down the Kuril Trench at 92 mm/yr.

Let's look more closely at some of the features visible in the Terra satellite image above.  The first is Klyuchevskaya volcano (also spelled Kliuchevskoi) in the lower-left part of the image.

This image was taken on October 11, 2010, at 1237 UTC (12:37 pm local time).  Note that the volcano is actively erupting a plume of ash.  The white on the flanks of the volcano are a mix of snow and ash and patchy white clouds are also visible.  Look carefully on the left side of the crater, see the little river of red?  That's a lava flow being picked up by the infrared sensors on the satellite (infrared radiation is emitted from hot objects).  Here's a close-up:

Klyuchevskaya is a stratovolcano and the highest peak on Kamchatka at 4,750 m (15,584 ft).  This volcano has erupted more than 50 times since it was first recorded in 1697 (and there's radiocarbon evidence of eruptions going back six thousand years).  That constant eruptive activity is actually a good thing in some ways - volcanoes that are constantly erupting like this are generally well-behaved and not too dangerous (although the ash plumes rise to 26,000 feet or more and can disrupt air traffic).  It's also a great place for volcanologists to study volcanic processes - the Kamchatka Volcanological Station was established at its base in 1935.

Klyuchevskaya from Global Volcanism Program

Another volcano seen in the image is Bezymianny (lower-left), which is just to the south of Klyuchevskaya volcano.  Note the shadow of the volcano indicating the Sun is to the south (expected in Kamchatka in October) and the plume rising from the crater.  This is just a steam plume (meltwater seeping into fractures and heating into steam due to the hot rock at depth) as no explosive activity was recorded at this time.

Bezymianny from Global Volcanism Program

Bezymianny was once though to be extinct, until it violently erupted in 1955-1956 and blew out the east-southeast side of the volcano leaving behind a horseshoe-shaped crater (very similar to the way Mt St Helens erupted in Washington State back in 1980).  A large lava dome now exists in the crater with intermittent explosive activing and pyroclastic flows.

The third major volcano in the Terra satellite image is Shiveluch which is located in the northeastern part of the Terra satellite image.  Shiveluch is one of the most active stratovolcanoes in Kamchatka and was erupting a plume of ash when this image was taken (crater is circled in red).

Shiveluch has been active for at least 65,000 years with dozens of major eruptions and uncounted minor ones.  The eruptions are characterized by the collapse of lava dome complexes leading to debris avalanches and lahars (flows of ash and water).  The last major eruptions of Shiveluch were in 1854 and 1964.

The large circular area seen is a 9 km (5.6 mi) diameter caldera that is breached on its southern side.  The 1964 eruption formed the area of brown debris flows seen in the lower part of the image.

Shiveluch from Global Volcanism Program

Scrolling around the large Terra satellite image, you can see a lot of other volcanic features (in some places, it almost looks like the area was struck by a storm of meteorites).  There's also a curious horsehoe-shaped structure near the center of the image.

It's an old volcanic caldera, breached to the southeast.  Extinct now, but once the site of a powerful explosive eruption that would have killed anything living within miles in that direction.

The river flowing north-south through the central part of the image also shows some neat features. It's a meandering river channel which is typically of a mature river in a relatively flat area.  The landscape, however, shows a number of scars indicating how the river channel has changed position over the years.

This is very similar to what's seen in the area of lower Mississippi River.  Meanders form loops in the river and the loops get cut off because rivers preferentially erode the outside bend of curves.  These loops then get left behind as horseshoe-shaped lakes called oxbows (note the oxbow to the left of the main river channel.  Eventually these oxbows stagnate into swamps and then fill in with sediments (as seen in the numerous scars in the image).

Another type of fluvial (stream-related) feature is seen in the river flowing east-west across the image.  There, we don't see meanders so much as we see a braided (anastomosing) channel.  These are typical of sediment-laden streams in flat areas typically draining off glaciers.

There are also some signs of life in this image with cultivated fields, a road, an airstrip and a town (right of the airstrip) in this incredibly remote place to live surrounded by constantly erupting volcanoes.

This is why Earth scientists like satellite image.  You can obtain a lot of information about an isolated area like this relatively easily.

Volcanoes in Kamchatka I

Kamchatka is a 1,250 km (~775 mi) long peninsula on the far eastern end of Russia separating the northern Pacific Ocean and Bering Sea from the Sea of Okhotsk.

Image from FlashEarth

As we can see in this image from Google Earth, just to the east of Kamchatka, on the ocean floor, lies the 10.5 km (34,450 ft) deep Kuril Trench.

This deep seafloor trench exists because the crust (lithosphere, technically) of the Pacific Ocean is sliding down that trench and subducting beneath the Sea of Okhotsk.

The plate tectonic interactions in this part of the world are somewhat complex.  As you can see in the diagram at left from Wikipedia, the Pacific Plate is sliding down the Kuril Trench (shown as a blue-barbed line east of the southern part of the Kamchatka Peninsula) underneath the small Okhotsk Plate.

The arrow shows the direction and rate of plate movement here.  The Pacific Plate is moving toward the northwest at a rate of 92 mm/yr (9.2 cm/yr or 3.6 in/yr).

Off the east coast of the central part of the Kamchatka Peninsula, things get complicated because there's a triple junction here.  The blue barbed line coming in from the west is the Aleutian trench which is just south of the arc of the Aleutian Islands coming off of Alaska.  The Pacific Plate is also subducting down the Aleutian Trench but here it's moving under the North American Plate with extends under the Bering Sea and into Asia.

Off the northern east coast of Kamchatka, the seafloor of the Bering Sea (the North American Plate) is subducting beneath the Okhotsk Plate.

All of this is a small part of the so-called Ring of Fire, the chains of active earthquake zones and volcanoes extending around the rim of the Pacific Ocean due to plate subduction down into deep seafloor trenches.

 Image from USGS This Dynamic Earth

What happens during subduction is that the descending slab of oceanic crust begins to melt as it sinks into the Earth's mantle providing magma for overlying volcanoes.  The subducting plate also sticks and slips as it slides down into the mantle causing frequent large earthquakes in such areas.

Image from PlateTectonics.com

Now that I've given some background, I want to share the incredible satellite image that was the impetus for this post.

This image was taken from the the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on the Terra satellite on October 11, 2010.  Terra is an Earth-observing satellite NASA runs in partnership with the aerospace agencies of Canada and Japan.

This image shows three volcanoes in Kamchatka - Klyuchevskaya, Bezymianny, and Shiveluch.  Klyuchevskaya and Shiveluch were currently erupting when this image was made.  These eruptions are from magma rising up through the crust and derived from the melting of the subducting Pacific Plate as explained above.

Click here to see the awesome 6277 x 8892 pixel image in all its glory.  In tomorrow's post I'll show a few close-ups and point out a number of interesting volcanic and fluvial (stream-related) features in this image.

Ever wonder what a Titanosaur penis looked like?

No, that's not a cheesy paleontologist pickup line, it's a serious topic of scientific inquiry according to some videos over at the Discovery Channel.

Go and watch them, they're actually quite interesting.

Unless you'd like to get a reputation for being an odd person (like I have), you might want to view these in the privacy of your own home!

Not a good start to the semester...

Today was supposed to have been the first day of classes for the spring semester where I teach.  Since there's a snow/sleet/ice storm now battering the Northeast, however, classes were cancelled.  Most people would love to get a snowday from work and stay home (and still get paid) but I don't like them.  I carefully plan all of the lectures for my classes so snowdays wreak havoc with my schedule.

Just look at that mess in the Northeast.  It's what Elliot Abrams of Accuweather calls a "slop storm" (not exactly a scientific term but certainly descriptive).

Today, for example, I was to teach the first lecture of an Historical Geology course.  It's a 4-credit lab course that has two 1.5 hour lectures each week (Tuesday & Thursday mornings) and a 3 hour lab (Monday afternoons).  Due to the snow day, I'm missing a 1.5 hour lecture.  While we have a snow day makeup built into the spring schedule, it's not until April.  The problem is that I need to talk about some things before lab next Monday and now I'll have trouble doing that in the one class I have left this week (and similarly for future Monday labs).  I'll probably just use some of the first lab day to continue lecturing and have the students finish up the labs on their own time.

Faculty on the other side of campus (you know, those social "science" and humanities types) don't often appreciate how schedule changes affect those of us with science labs we're trying to coordinate with lectures.  Those in the college administration, of course, typically have a background in those "softer" academic areas.

That's why I hate snowdays.  Even though I get a day off, it actually makes more work for me when I return to school since I now have to modify how I do things.  I'm also department chair and there's work I need to do for that as well (stuff I couldn't really do until the semester began and can't do at home).  Now that work starts piling up also.

I should count my blessings since I'd rather go to work than get a day off.  Not many people can say that about their jobs!

ARkStorm

Something else to keep you up at night (especially if you or your loved ones live in California).

The United States Geological Survey (USGS) Multi Hazards Demonstration Project (MHDP) just released the results of a study called ARkStorm (the AR stands for Atmospheric River).  It's a study of what would result from a repeat of the intense California winter storms of 1861 and 1862 that devastated the central valley of California.

The idea is that policy makers, utilities, and emergency response agencies can put plans into place so that we have a strategy for dealing with such an event when it inevitably occurs at some point.

The winter storms which occurred from December 1861 to January 1862 were unbelievably intense.  The turned California's Central Valley, an area 250 miles north-to-south and 20+ miles east-to-west into a temporary lake!  They had to move the state capital from Sacramento to San Fransciso for a while.  In addition, geologists have uncovered sedimentological evidence that similar mega-storms occurred in years 212, 440, 603, 1029, 1418, and 1605.  While rare, these storms could reoccur at any time. 

Picture at left shows K Street in Sacramento during February, 1862.

The report is very interesting reading detailing what such a storm might look like and its devastating effects in terms of flooding, debris flows, infrastructure damage, agricultural effects, economic impact, etc.  We're talking an estimated 725 billion dollars worth of impact!

Some of the key findings from the report's Summary:

· Megastorms are California's other "Big One"
· An ARkStorm would be a statewide disaster
· An ARkStorm could produce an economic catastrophe
· An ARkStorm is possible, perhaps inevitable

The Disappearing Spoon

Just finished a decent read, The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements by Sam Kean (Little, Brown and Company, 2010).

It's a history of the periodic table of the elements and full of interesting stories about the elements.  Why did Ghandi hate iodine?  How can we trace the trail of Lewis & Clark with mercury?  Why did the Japanese used cadmium-tipped missiles to shoot Godzilla?  How did Marie Curie make her husband jealous with radium?  What element will make a sppon disappear in a hot cup of tea?  Will new elements continue to be discovered?

Kean writes well and is occassionally amusing as he takes readers on a tour of the elements grouping them together in interesting ways (Elements in Times of War, Artistic Elements, Elements as Money, etc).  He discusses many of the major players in 19th and 20th century physics and chemistry from Mendeleev to Seaborg and provides a lot of interesting tidbits and stories about them.

The book is written for a general audience with a basic background in science.  I enjoyed reading it.

Garnets

The word garnet does not denote a single mineral but rather a group of minerals which have similar crystalline structures and physical properties.  The garnets generally fall into two chemically similar groups - the pyralspites and ugrandites.

The pyralspite garnets form the first group.  These are magnesium (Mg), iron (Fe), and manganese (Mn) garnets which all have aluminum (Al) as the second element in their formula.  There are three common pyralspite mineral species:

Pyrope - Mg₃Al₂(SiO₄)₃

The name pyrope derives from the Greek words for "fire" and "eye" due to its deep red color.  Good quality pyropes can be cut into ruby-like gems.

Pyropes are primarily associated with ultramafic igneous rocks (mantle peridotites) and ultrahigh-pressure metamorphic rocks (eclogites) formed during the deep subduction of basaltic seafloor.

Pyrope can be difficult to distinguish from almandine garnets since they form a solid-solution series between each other.  Pure pyrope and pure almandine are the exception, typically pyrope has some Fe and almandine has some Mg mixed into the minerals.

Almandine - Fe₃Al₂(SiO₄)₃

The name almandine (sometimes called almandite) comes from Alabanda, a location in ancient Asia Minor (modern Turkey).  It's also a deep red, sometimes looking purplish, and, as mentioned above, sometimes difficult to distinguish from pyrope.

Almandine is the most common type of garnet and typically the garnet found in garnet schists.  The deposits at Gore Mountain, NY (the subject of a future post) are mostly almandine and mined for use as an industrial abrasive.

Spessartine - Mn₃Al₂(SiO₄)₃

Spessartine (sometimes called spessartite) is named for Spessart in Bavaria, Germany.  Spessartines come in a variety of colors but the most striking are orange.

Spessartines form a solid-solution series with almandine and can thus have Fe mixed into them (they're the reddish spessartines).

Spessartine garnets are most often found in granite pegmatites or Mn-rich metamorphic rocks.

The ugrandite garnets form the second group. These are chromium (Cr), aluminum (Al), and iron (Fe) garnets which all have calcium (Ca) as the first element in their formula. There are three common ugrandite mineral species:

Uvarovite - Ca₃Cr₂(SiO₄)₃

Uvarovite was named after Sergei Semenovitch Uvarov (1765-1855), a Russian mineral collector.

Uvarovite is a rare garnet species but sought out by collectors due to its beautiful emerald-green color.

Uvarovite typically occurs from the metamorphism of silica-rich limestones and associated with serpentine and chromite.

Grossular - Ca₃Al₂(SiO₄)₃

The name grossular (also called grossularite) is derived from grossularia, the subgenus name for the gooseberry.  Grossular is the most colorful of the garnets with orange, green  (called tsavorite), cinnamon brown, or reddish (hessonite) varieties.

Grossular forms in contact-metamorphosed limestones which lack aluminum.  Grossular is the Vermont state gemstone, notable specimens come from the Eden Mills are in the northern part of the State.

Andradite - Ca₃Fe₂(SiO₄)₃

Andradite was named for the Brazilian mineralogist José Bonifácio de Andrade e Silva (1763-1838).

There are three color varieties of andradite - black (melanite), green (demantoid), and yellow-green (topazolite).  Demantoid (the green is from chromium) is very rare and an expensive gemstone.

Andradite also forms in contact-metamorphosed limestones.
 
Since garnets were values since ancient times as attractive gemstones there are a host of confusing names (some technically incorrect today) referring to all of the different varieties of these six basic garnet species.