In the week between Christmas and New Years, my friend Casey and I took a trip to Northern Ireland. We stayed with her friends Jodie and Rory in Portadown, and on our first full day, Jodie took us out to Armagh (pronounced "Ar-maa"), where she teaches at a primary school. Saint Patrick apparently decided that Armagh was going to be the seat of Irish faith, and he decreed that the Archbishop of Armagh would have preeminence over the rest of Ireland. Of course, Northern Ireland is a land still strongly divided along religious lines. Though it's no longer violent, there is still strong "us and them" sentiment among the Northern Irish people I spoke to. Jodie took us to visit Armagh's two cathedrals: one Catholic, one Protestant. They occupy the two highest hills in town (of course!).







Flatscreen television monitors inside the Catholic cathedral, so that worshippers can see what's going on behind those massive columns.










I was delighted to note a bunch of geological details in the two buildings. This image is of the limestone that makes up the exterior of the Catholic cathedral. It's full of fossils. Here's some spiral-shelled creature. Not sure what exactly. Width of fossil is about 1 inch.












Fossil coral colony on the exterior of the Catholic cathedral. Pound coin for scale.











The Protestant cathedral (Church of Ireland) is made of a greater variety of stones. Most of it is sandstone, and the sandstone hosts deposits of iron oxide (hematite) in precipitated horizons called Liesegang banding. Though it looks strongly layered, the Liesegang banding is not sedimentary bedding. In this block, bedding is horizontal, and the Liesegang banding was deposited by groundwater at an angle to the bedding. Pound coin for scale.


The lower part of the Protestant cathedral is made of conglomerate/breccia. The large clasts are fairly angular, indicating that they did not travel far from their source area before they were deposited. This makes it more a breccia than a conglomerate. Unlike a lot of true breccias, however, this rock is pretty well stratified (layered), indicating that it was deposited by moving water: a characteristic of conglomerates. Pound coin for scale.



Here's one particular clast from the conglomeratic lower part of the Protestant cathedral is made of conglomerate/breccia. In it you can see fossil fragments, apparently of the same coral visible in the Catholic cathedral's stone. Pound coin for scale.






Of greatest interest to me was the fact that James Ussher was the head of the Church of Ireland (the full title is "Primate of All Ireland") from 1625 until 1656. As I mentioned earlier, this means that he was the Archbishop of Armagh. Ussher has a reputation as the most scholarly of the historial archbishops, and he is particularly known to geologists because he attempted to calculate the age of the Earth using the Bible. By estimating generational times and tracking geneaological lineages in Scripture, Ussher proposed that moment of the Earth's creation was the evening immediately before Sunday, October 23, 4004, B.C. It is from his work that the specific notion of a young Earth arose. According to Ussher and his subsequent legions of young Earth creationists, our planet is only 6000 years old (well, 6011 years, to be precise.) Of course, this caused some tension with geologists of the time like James Hutton, who realized that if the uniformitarian concept is correct, the Earth must be vastly older than 6000 years (or, to be precise, 5750 years old at the time Hutton himself was mulling it all over in the mid-1700s). Later discoveries by the many geologists inspired by Hutton, in particular that of radioactive decay, provide quantitative evidence that the Earth is in fact much older than 6000 years. Three different lead isotope systems, for instance, provide ratios of radiogenic lead to non-radiogenic lead that suggest the Earth is about 4.5 billion years old. That's approximately 6 million times older than Ussher calculated -- a vast, vast difference. In spite of the overwhelming physical evidence for an ancient Earth, I still find that many students enter my classes with a perception that the Earth is less than 10,000 years old. I have James Ussher to thank for that. It was a pleasant moment for me to visit his cathedral and ponder his lasting effects.

Labels: armagh, fossils, geology, northern ireland, ussher

Gigantopithecus blacki is the name of an extinct species of giant ape that existed in China 300,00 years ago. It was between 9 and 10 feet tall! Imagine seeing that as an early human expanding into that area -- easily imaginable as the source of our legends about giants. Because it apparently ate bamboo and fruit, it may have competed with pandas, too.

Labels: fossils

My dad has been a stamp collector for a long time. He edits the Indochina Philatelist, a journal which covers stamps and postal history of French Indochina (nowadays that's Viet Nam, Cambodia, and Laos). Over the years, I've helped him out with proofing the journal and doing some art (for instance, the title of the journal, rendered in bamboo letters, is something I can claim credit for).

Labels: geology, stamps

The term "blog" is ten years old this month. A good time to finally get on board, I reckon!

Labels: blogs

Several websites are dedicated to monitoring Earth's seismicity over time. They make an interesting comparison in terms of graphical representation, considering that they are all reporting on the same information. Check them out and decide which one you think does the best job.

Earthquake Watch is a homemade site using Google Maps to show quake locations and magnitude. It shows magnitude, but only quakes in the last day, without differentiating between quakes in the past hour and longer times. Because it's done using Google Maps, it can be centered wherever you want -- or wherever the earthquakes happen. This is in contrast to the next two options, which have a fixed map centered on the Pacific Basin.

The USGS uses a nice physiographic map as the base for their information display. A series of colored squares of different sizes show magnitude and time of the quake. This is an advantage over the first site: more information revealed in the same amount of space. Still, like the first site, the map is small -- roughly 40% of the total "real estate" available on the screen.

The IRIS Seismic Monitor is my favorite of the bunch. It has a large map (~70% of the screen) with blinking circles of different sizes and colors show information about when a quake happened: last hour, last day, last two weeks, and the past five years. It also offers an option for a huge map (larger than the whole screen). Additionally, it offers a global night shadow -- so you can see which portion of the planet is in daylight, and which half is sleeping through the night.

Labels: earthquakes, graphics

Mass wasting is the downslope movement of Earth materials (rock, soil, debris) under the influence of gravity. Landslildes, rockfalls, slump, and creep are all examples of mass wasting. Today in Indonesia's island of Java, there were a series of landslides triggered by lots of rain. Rain often acts as a catalyst for mass wasting, for several reasons. First, rain is heavy. Once soil gets waterlogged, it just plain weighs more. Heavier masses are more likely to slide than petite ones. Second, water expands soils, pushing outwards from pore spaces. This expansion factor can cause slopes like the hillsides in this AP photograph to increase their gradient every so slightly -- sometimes beyond a critical angle called the "angle of repose". When a slope is below the angle of repose, it stays put ("reposes"). Above the angle of repose, it slides. Lastly, and possibly most importantly, water acts as a lubricant, reducing frictional inertia and allowing soil particles to slide past one another. I call this the "Slip N Slide" effect -- consider the difference between going down a waterslide with water and one that's dry. The water "greases the skids" and facilitates movement. Indonesia is particularly susceptible to landslides because of volanically-steepened slopes and heavy tropical rains. Sometimes, its landslides are triggered by seismic shaking. More on today's landslides can be seen on the BBC's website.

Labels: indonesia, landslide, mass wasting

NPR ran a story this morning about the destruction of Oculina deep-water coral reefs off of Florida. Thanks to a bunch (~70,000) photographs taken of the reefs in the 1970s, we can compare before and after imagery of the strange deep-water ecosystem. John Reed, of the Harbor Branch Oceanographic Institution, published a study on the reefs' destruction in the Bulletin of Marine Science. The area was trawled heavily for shrimp in the interim, and most of the coral structures have been smashed to pieces. Listen to the full story here.

Labels: corals, reefs

An update on my Prius: I've driven about 250 miles since I got it last week, and over that period I'm getting an average of 46.7 miles per gallon. I am pleased. Merry Christmas!

Labels: action, global warming, prius

The "Astronomy Picture of the Day" web site showcases a different image of the Cosmos every day. Nice! I've got it on my RSS feed, so everyday when I log into my Google account, I've got an image like this one greeting me. Clicking on the image takes you to a larger version and a more detailed description of the pic.

Labels: astronomy, websites

National Geographic has a nice overview of the basic ideas behind global warming here.

Labels: climate change, global warming

Global warming bummer for the Italians: chikungunya, a tropical disease native to the Indian Ocean region (a relative of dengue fever), has moved in. It's carried by tiger mosquitoes, which are able to thrive in Italy now that the temperature's gone up. The New York Times has more on this story.

Labels: climate change, global warming

Okay, so we all know that carbon dioxide has this property of being selectively transparent, and that it is accumulating at greater concentrations in Earth's atmosphere because the rate that it is being produced by human activities greatly exceeds the rate it is removed by natural processes. That's the global warming issue in a nutshell. But there's another aspect to climate change that hasn't gotten as much press: ocean acidification.

Much of the carbon dioxide produced since the Industrial Revolution has been absorbed by the oceans. Global warming would have been as noticeable as it is today much earlier had the oceans not acted as a "carbon sink" in this fashion. But the oceans can't absorb CO2 forever without consequence. When CO2 dissolves in H2O, it produces H2CO3, also known as carbonic acid. (top image)

Caldeira and Wickett published a study in 2003 in which the explored the consequences of adding all this extra acid to the oceans. The oceans are large, so changes to their pH take place slowly, but it looks like the ocean's pH is dropping (becoming more acidic) as it absorbs the extra CO2 from the atmosphere. They made some predictions (second image) about how projected emissions of CO2 will influence the amount of CO2 in the atmosphere (shown here as pCO2, which translates as the "partial pressure of carbon dioxide in the atmosphere), and then how that would influence the ocean's pH over a range of depths over the next millennium. As you might expect, their model shows surface waters becoming acidic first, because they are in direct contact with the CO2-rich atmosphere. Oceanic mixing propagates the acidic waters to the depths over longer timescales. They predict a maximum reduction of 0.7 pH units in surface waters, starting around the year 2200.

How will this effect marine life? Remember that lots of marine creatures make their skeletal material (hard parts) out of the mineral calcite, and calcite dissolves in acid. (In my classes, we put a drop of hydrochloric acid on a rock sample to determine if it is calcite.) Consider the effects on two kinds of plankton: coccolithophores and pteropods. The third and fourth images here show scanning electron micrographs of how skeletal material reacts to acidified conditions. The third image is from a study by Ulf Reibesell of the University of Norway, who grew coccolithophores in a series of model "ocean" tanks that had equilibrated to an "atmosphere" containing 300 ppm and 800 ppm CO2. For reference, pre-Industrial CO2 values were about 280 ppm, and today's CO2 values are about 380 ppm. You can see that the calcareous plates of the coccolithophores are smaller, thinner, and more degraded in the more acidic water. The fourth image shows the results of a similar experiment on a pteropod, by Orr, et al. in 2005. (A pteropod is a kind of planktonic snail.) The pteropod was placed in a tank of water undersaturated with respect to aragonite (a polymorph of calcite) for 48 hours. Sub-images b, c, and d show degradation of the snail's shell in those acid waters, and sub-image e shows a the surface of a normal pteropod shell for comparison.

Here's some model predictions of ocean pH from Scott Doney in a 2006 paper in Scientific American. Note that the northern Pacific Ocean becomes marginally saturated with respect to aragonite by the end of the century, and the Southern Ocean will be undersaturated by then. The skeletons of organisms with calcareous shells in those waters will begin to dissolve! So far, the pH drop has been only about 0.1 pH unit, but it is expected to hit around 0.3 pH units by 2100. It's hard to imagine how fundamental a change this will be to oceanic ecosystems!

Now, a new study in Science by the Coral Reef Targeted Research Group concludes that it's not just these high-latitude ocean water. Global warming kills tropical coral reefs, too. They consider the effects of ocean acidification as well as the effects of "bleaching" (when warm corals eject their symbiotic algae).

Labels: climate change, CO2, ocean acidfication

From The Onion: Bush Acknowledges Existence of Carbon Dioxide

Labels: global warming, humor

So... I've been talking to my students for years about the science of climate change. I've stated as plainly as I can that I'm convinced that emissions of greenhouse gases, in particular CO2, are warming up our planet. To my long-term, whole-planet style of thinking, this is a MUCH bigger issue than something like the war in Iraq. Iraq is "merely" a conflict between two (or a half-dozen) countries. On the other hand, climate change is BIG -- it affects all of the planet's surface (albeit to differing degrees) and it's going to last an unimaginably long time (if all continues along the present trend). The rates at which geologic processes extract CO2 from the atmosphere are way too slow to compensate for the breakneck pace we're generating atmospheric CO2 through the burning of fossil fuels (and forest biomass).

But besides educating students, what am I doing about it? Two days ago, I took a big step towards putting my money where my mouth is. I bought a Toyota Prius, one of the current generation of hybrid vehicles that are much more fuel efficient and produce less greenhouse gases. The Prius is ranked by the EPA as getting 45 miles per gallon in the city and 48 m.p.g. on the highway. It's classified as a partial-zero emissions vehicle.

Here's a comparison for several cars from the EPA's data. Hopefully you can see why I opted for the Prius. Maybe in another five years, there will be a mass-market electric vehicle. That's what I really want for Christmas!

Make and model	Engine	Fuel	Drive	Air pollution score	Fuel-economy (MPG) City/Highway	Greenhouse gas emissions score
Toyota Prius	1.5L 4 cyl	Gasoline	2WD		48 / 45
Honda Civic Hybrid	1.3L 4 cyl	Gasoline	2WD		40 / 45
Honda Insight	1.3L 4 cyl	Gasoline	2WD		45 / 49
Mazda Tribute Hybrid	2.3L 4 cyl	Gasoline	2WD		29 / 27
Lexus LS 600 HL	5L 8 cyl	Gasoline	4WD		20 / 22
Jeep Grand Cherokee	3L 6 cyl	Diesel	4WD		17 / 22
Jeep Grand Cherokee ("flex-fuel")	4.7L 8 cyl	Ethanol Gasoline	4WD		9 / 12 ethanol 14 / 19 gasoline
Hummer H3	3.7L 5 cyl	Gasoline	4WD		14 / 18
Bentley Continental GTC	6L 12 cyl	Gasoline	4WD		10 / 17

Labels: action, global warming, prius, teaching

January 30 may be a bad day on Mars. A space rock discovered in November of this year has a 1-in-75 chance of smacking into the red planet on that day. The rock is about the same size as the one inferred to have leveled the forest in a big swath of Siberia in 1908 (in what is called the Tunguska Event.) The amount of energy released then is estimated to be approximately the equivalent of a 15 megaton nuclear bomb. More details here.

Labels: astronomy, mars, meteors

New research indicates that one possible source for the decline in Atlantic sea-surface temperature in 2006 may have been dust from the Sahara Desert. The image at left shows a dust plume being blown westward off the coast of Mauritania.

William Lau and Kyu-Myong Kim of NASA's Goddard Space Flight Center have concluded that airborne Saharan dust over the Atlantic was likely responsible for low temperatures because it effectively blocked sunlight from reaching the ocean's surface. Their research was published in EOS and the International Journal of Climatology.

In 2005, when the Atlantic was warmer, there were 15 hurricanes (including Katrina and Rita). In 2006, many people were expecting similar numbers and strengths of storms. However, there were only five that year due to lower sea-surface temperatures. Lau and Kim estimate that the dust was responsible for 30%-40% of the cooling effect.

Read more about it here and here.

Meanwhile, another team of researchers has found that these well-traveled dust particles may be a potential vector of disease. In the current issue of Environmental Microbiology, Anna Gorbushina and William Broughton (of the University of Geneva) report that germs can "hitchhike" on dust particles, allowing them to spread from continent to continent. The researchers used geochemical analyses to determine that samples of dust originally collected by Charles Darwin in Barbados actually originated in Africa. Furthermore, bacteria and tiny fungi were found stuck to the dust grains. The species found were not pathogenic (disease-causing), and the researchers note that most pathogens are not hardy enough to survive a long voyage on the Dust Express.

Read more about it here.

Labels: disease, dust, global warming, hurricanes, satellite imagery, silt

A well-illustrated article by NASA's Earth Observatory discusses the issue of coal mining in Appalachia. Estimates are that we have 100 years or more coal reserves in the world -- far more than oil. The problem is, coal is dirty. Appalachian coal in particular is high in pyrite (FeS2), so that when it is burned, sulfuric acid is generated.

And then, of course, there is the issue of greenhouse emissions. When we heat or get electrical power from the burning of coal, we are reversing an ancient photosynthetic reaction. In the Carboniferous, great swampy deltas (much like the modern Mississippi Delta) stretched across what is today West Virginia. Great rivers draining the young Appalachians flowed west into a shallow epeiric sea. In these muddy deltas, plants grew in profusion. Those plants did what modern plants do: they sat in the sunlight and used its energy to fuse CO2 and H2O into sugars -- plant food. Before they got a chance to use that constructed food, and before any animals had a chance to eat the plants, they were smothered beneath additional layers of sediment, and the efforts of their photosynthesis were locked away underground. This went on for millions and millions of years. Now, humanity has discovered that coal burns well, releasing energy originally generated by the Sun 300 million years ago. Using coal for energy reverses the ancient photosynthetic reaction. When we burn coal, we are combining the coal's "carbohydrates" with oxygen, and re-producing the initial ingredients (CO2 and H2O) in the process. Of course, when water vapor in the air reaches a high concentration, it condenses and precipitates. Carbon dioxide is also removed from the atmosphere by geologic processes, but at a much slower rate. Hence the rise in atmospheric CO2 levels since the Industrial Revolution (when coal-burning picked up pace).

The Earth Observatory article deals with another issue, though: the question of how best to get at coal, given that it's underground in strata with other rock layers atop them. Every month, it seems like there is an item in the news about how there's been an accident in some underground coal mine somewhere in the world, always with a dozen or more miners killed or trapped. In West Virginia, strip mining is a favored tactic. It's safer to coal miners because it occurs at the surface, but there's the rub: The surface is also where everything else happens, too. When miners strip away the overlying rock layers, they also strip away the forest and everything that lives there. Often, unwanted rock is dumped into neighboring valleys, which causes a lot of stress on the freshwater ecosystems present in streams draining that valley.

Check out the article here. It is illustrated with great maps and satellite photos.

Labels: CO2, coal, global warming, mining, satellite imagery

One of the points of the this new blog enterprise is to introduce my students (& interested others) to a couple of the places I go on the web for geology news. So, to keep you busy over the holiday break, here's a few sites I've been checking out lately:

Solar Power Rocks
Highly Allochthonous
Earth Observatory (NASA) Picture of the Day
USGS stream gauge for the Potomac River at Little Falls
Mauna Loa Carbon Dioxide measurements (NOAA)

Here's the main image from that last one. Ponder that for meaning.



















Enjoy!

Labels: blogs, geology

Over the Thanksgiving break, I traveled to Vieques, a small island east of Puerto Rico. Vieques is one of the Greater Antilles, the large Caribbean islands (also including Cuba, Hispaniola, and the main island of Puerto Rico). Its rocks are mainly igneous rocks (both intrusive and extrusive), mantled with a layer of tropical limestone deposited during times of higher sea level. Here's a few photos from the trip.

My morning cup of coffee, and the view to the south over the Caribbean Sea.












A beautiful iguana.













Xenolith in granite (1 of 3) . Keys for scale.












Xenolith in granite (2 of 3) . Keys for scale.













Xenolith in granite (3 of 3) . Keys for scale.












Fine-grained granitic dike ("aplite") cutting across coarse-grained granite, Esperanza.












Epidote pods in metamorphosed basalt. Keys for scale.














Looking the other way on the beach -- to the east. I like seeing cactus near the shore. It reminds me of Baja California, Mexico.










The beach near Esperanza, Vieques (looking west).












Epidote veins in metamorphosed basalt. Keys for scale.

Labels: geology, puertorico

In this blog, I'll be posting information related to current events, observations, travels, classes, and other stuff related to geology & teaching geology.

Labels: blogs, geology