Bandelier National Monument

One of the neat things about Los Alamos is that Bandelier National Monument is only a few minutes away. The volcanic tuff at Bandelier erupted from the Valles caldera about 1.25 million years ago, but it's not just a site of geologic interest; it's also an archaeological site. Bandelier refers to Adolph Francis Alphonse Bandelier, a Swiss-American archaeologist who conducted research into the history of the Pueblo people in the American southwest.

On the drive to the park visitor center, there's some fantastic columnar jointing in the tuff. (Columnar jointing occurs when hot volcanic material, either a lava flow or pyroclastic deposit, cools from the outside in and shrinks, forming cracks. These cracks often create geometric shapes that extend down into a deposit, creating columns.)

In the Frijoles Canyon, there are scads of cliff dwellings and the ruins of villages of the Ancestral Pueblo people, who moved into the region around 10,000 years ago. (They were formerly called "Anasazi" by archaeologists, but today's Pueblo people consider the Navajo term disrespectful). The village below was most highly developed in the late 1400s, and contained multistory dwellings and storage buildings. 

The cliff dwellings at Bandelier are located mostly on the south side of the canyon, which means that they stay cool in the summer and warmer in the winter. It was a very hot day when I visited, and there was a significant temperature drop once you were sheltered by the cliffs. 

Many of the cliff dwellings used to have structures built in front of them, leaving the caves as back rooms. Holes for the ceiling poles are still visible in the tuff, which is relatively soft and quite easy to hollow out.

One of the most interesting sites in this area of the park is known as the Alcove House, a huge shallow cave in the canyon wall. It holds a reconstructed kiva and the remnants of dwellings, but it's quite a challenge to reach  - and not at all fun for anyone who's afraid of heights! Like many of the other cliff dwellings in the park, the Alcove House is only accessibly by ladder; unlike the dwellings in the earlier photos, the ladders are very long (140 feet altogether). The photo below shows one of three that you have to climb to get up there!

It's a little hard to take photos of the whole alcove when you're in it, but the view down Frijoles Canyon is excellent. It also highlights how the natural propensity of the Bandelier tuff to erode into caves - something that the first visitors to the canyon certainly noticed and took advantage of!

I only had one day to explore Bandelier, which is unfortunate (it has more than 70 miles of trails), but I'm glad I had the chance to visit on this trip. This area offers a fascinating blend of volcanology and archaeology, something that I (with my sadly unused archaeology minor) really appreciate. 

Flatirons ≠ pyramids, but they're still cool

I've noticed a few stories recently about Sam Osmanagich, a Bosnian archaeology enthusiast who claims to have discovered several 12,000-year-old 'pyramids' in the Balkans. The whole 'pyramid' saga mainly concerns a case of mistaken identity - the pyramids are just hills - and Indiana-Jones-style archaeology (by which I mean not very methodical, scientific or objective) on Osmanagich's part, and you can read more about it at the links below:

National Geographic: Pyramid in Bosnia - Huge Hoax or Colossal Find?
Smithsonian Magazine: The Mystery of Bosnia's Ancient Pyramids

They're really not hoaxes or mysteries, though - just badly misidentified. I minored in archaeology in college, and it really makes me cringe to see something so pseudo-scientific be accepted by so many people, even becoming a point of national pride in Bosnia. Archaeology has become a very scientific process, and properly-conducted archaeological digs are just as methodical as anything we do as geologists. Digging holes in a hillside, finding layered sandstones and conglomerates and then declaring that they're poured concrete mostly because they look like concrete is really crappy science. (There are also a lot of archaeologists who are unhappy about the whole situation because the 'pyramid' digs could potentially destroy a lot of genuine archaeological sites, which that area of the Balkans apparently has in abundance.)

Anyway, the situation is a great big mess. But what I found really interesting in the Smithsonian article was the (much more plausible) geologic explanation for the pyramids. Here's what the article says:

Visoko lies near the southern end of a valley that runs from Sarajevo to Zenica. The valley has been quarried for centuries and its geological history is well understood. It was formed some ten million years ago as the mountains of Central Bosnia were pushing skyward and was soon flooded, forming a lake 40 miles long. As the mountains continued to rise over the next few million years, sediments washed into the lake and settled on the bottom in layers. If you dig in the valley today, you can expect to find alternating layers of various thickness, from gossamer-thin clay sediments (deposited in quiet times) to plates of sandstones or thick layers of conglomerates (sedimentary rocks deposited when raging rivers dumped heavy debris into the lake). Subsequent tectonic activity buckled sections of lakebed, creating angular hills, and shattered rock layers, leaving fractured plates of sandstone and chunky blocks of conglomerate. 

In early 2006 Osmanagich asked a team of geologists from the nearby University of Tuzla to analyze core samples at Visocica. They found that his pyramid was composed of the same matter as other mountains in the area: alternating layers of conglomerate, clay and sandstone.
Nonetheless, Osmanagich put scores of laborers to work digging on the hills. It was just as the geologists had predicted: the excavations revealed layers of fractured conglomerate at Visocica, while those at Pljesevica uncovered cracked sandstone plates separated by layers of silt and clay. "What he's found isn't even unusual or spectacular from the geological point of view," says geologist Robert Schoch of Boston University, who spent ten days at Visoko that summer. "It's completely straightforward and mundane." 

"The landform [Osmanagich] is calling a pyramid is actually quite common," agrees Paul Heinrich, an archaeological geologist at Louisiana State University. "They're called ‘flatirons' in the United States and you see a lot of them out West." He adds that there are "hundreds around the world," including the "Russian Twin Pyramids" in Vladivostok. [From pages 2-3 of the article]

Well, if you're trying to draw attention to the fact that someone's mistaking a geological formation for a man-made structure, I guess saying it isn't "unusual or spectacular from the geological point of view" is a good way to do it. But I think that flatirons are still pretty neat, even if they're made out of conglomerate, which as a volcanologist I will have to admit is not on my 'most exciting rock' list.

I've seen a few good examples of flatirons in my time out West, and I'm always impressed by the forces it took to move all that rock around. Here are some novaculite flatirons from the Big Bend, Texas region:

A great Michael Collier photo of the flatirons at Waterpocket Fold in Utah, which is part of Capitol Reef National Park:

Copyright (C) Michael Collier; hosted on the AGI Earth Science World Image Bank

(Michael Collier is an amazing photographer and a great person; I was lucky enough to meet him while I was working at AGI. I dare you not to buy a book of his photos once you've seen a few.)

And probably the most famous US flatirons, the Flatiron range just outside of Boulder, Colorado:

From Wikipedia

It's not hard to see how one of these things could get covered over with soil and vegetation and look like it was man-made. But pure observation that isn't backed up by data will give you bad results every time, and flat, triangular rock formations do not a pyramid make. It's really too bad that so many people in Bosnia are getting excited about their flatirons because they think they're remnants of an ancient civilization, and not because they're a neat geological formation that tells us about the landscape evolution of that part of the Balkans. But we can't all be geologists, I guess...

Geology and the movies again...or "Why Disney's Pocahontas Briefly Makes Me Want To Scream At The TV"

This is actually an older post I've been sitting on, but I wanted to get something posted this week, even if it's not about current events.

I love watching Disney movies, but occasionally the scientist gets in the way of the nostalgic enjoyment. I was reminded of this when "The Virginia Company" came up on my music player's shuffle list. Pocahontas, which came out in 1995, is set in an area that I'm now very familiar with (the Historic Triangle, home of Yorktown, Williamsburg and Jamestown). It's also on the Coastal Plain, which William & Mary's Geology Department is very favorably situated to study. In fact, unless you drive west for an hour or so, all you see in that part of Virginia is Coastal Plain. Aside from the cool fossils and some of the sedimentary features (and a big honking impact crater, although you can't see it) the Coastal Plain has relatively little to interest a volcano nut - I had to go out to Richmond to see any hard rock aside from river cobbles.

From the Geology of Virginia Website at W&M (click to view the bigger version).

That doesn't mean I didn't pay attention to the Coastal Plain geology. I did - and that's why seeing the beautiful landscapes that show up during John Smith's bold adventuresomeness in the "Mine, Mine, Mine" sequence irritates me enough that I want to smack the animators.


Where the hell did that mountain come from? (For that matter, why is it magically spouting a waterfall?) Did any of those animators actually go to Jamestown? Or look at a photo? Or a map? Jamestown is pretty much in a swamp, which was a really poor choice to begin with (one might assume that the colonists weren't thinking about the scenic needs of future moviemakers when they landed there). There are no mountains, no waterfalls, and NO CLIFFS there...

...unless you count the crumbly sandy ones along the rivers.

See? Not impressive*. What is impressive is that John Smith apparently had the ability to teleport himself to the Piedmont in the course of the musical number, because you ain't getting those rolling hills in Eastern Virginia. And the scene where Pocahontas jumps over a waterfall from a tall rocky cliff means that she managed to teleport all the way out to the Blue Ridge, because you don't get waterfalls without bedrock, and the Coastal Plain doesn't have it.

The one thing that the movie does get right about the geology is that you'd have a hard time finding any gold on the Coastal Plain. In other parts of Virginia, certainly, but on the Coastal Plain, you sometimes have trouble just finding dirt, much less gold. (There is a LOT of sand out there, however.)

I'll ignore all the film's other inconsistencies here - screwing up all the Native American names, and the whole John Smith/Pocahontas thing, which didn't really happen - since other people have ripped into them much more eloquently than I could. Let's just say that while the Disney crew might have had good intentions, they managed to both insult Virginia's current Native Americans and perpetuated a beloved but totally inaccurate American myth. AND annoy the geologists.

I'm not saying that the more historically accurate movies are much better, mind you. The New World, which actually was filmed near Jamestown (the movie people hung out in Williamsburg when they weren't filming, which the W&M crowd thought was pretty cool), is a mind-numbing artsy-fartsy epic that drags on until you find yourself wanting to join the colonists who are croaking from malnutrition. It does get the utter stupidity of trying to found a colony on swampland that the natives obviously aren't even bothering with, as well as the oppressive heat and humidity and clouds of biting insects right, but in this case accuracy doesn't make for entertaining cinema. (And those actors really were out in an Eastern Virginia summer, which makes me feel really sorry for the ones who had to wear wool. I spent one summer in Williamsburg and immediately vowed never to do so again, because I like to breathe air rather than soup.)

In the end, I do realize that Pocahontas is a cartoon, and Disney, and geologic accuracy was not a major concern of the movie. But I do feel like the animators cut some corners and went for flashy rather than putting in the effort to reproduce what the Jamestown colonists might really have seen when they arrived in what would eventually become Virginia. For a movie that was otherwise beautifully animated, that was a real disappointment.

And I cannot forgive the cliffs. :)

*In fact, we reduced what little impressiveness they have by initiating multiple mass wasting events just by digging.

Go for the art, stay for the volcanoes

Happy New Year! Here's to a successful, productive, safe, and above all fun new year. I've recently noticed that I've been added to a list of the 100 Best Blogs for Earth Science Scholars, which is quite an honor, and especially since I'm in such great company. Seems like a good way to start off the year to me!

A few days ago I went to Washington DC to get my bi-yearly fix of the museums, which (for me) generally means drooling over the volcanic rock displays in the Natural History museum and scarfing down gelato in the in the cafe between the National Gallery buildings. (I also saw the newly-renovated American History museum, which was somewhat unimpressive, and the new Ocean Hall at NMNH, which was awesome. Callan's review pretty much covers everything I could come up with to say.)

My favorite stop of the day, however, was in the East Building of the National Gallery. They're currently hosting an exhibition about pre- and post-eruption Pompeii called Pompeii and the Roman Villa: Art and Culture around the Bay of Naples. Most of the exhibit is devoted to the way that wealthy Romans decorated their homes, and how they liked to copy and emulate Greek art, and it's really neat; the frescoes are especially beautiful, and the statuary, while probably not something I'd want in my own home, is incredibly lifelike and masterfully done. (It's also very cool to look Julius Caesar in the eye, because you get a sense of who the man was rather than the legend.) Unfortunately, there was no photography of any kind allowed in the exhibition, so I can't show you what was on display. There is a pretty neat video about the exhibition on the NGA website, though.

The most exciting part of the exhibit, in my opinion, wasn't the sculpture or the frescoes, but the room that showed 18th-century romanticizing of the 79 A.D. eruption. Why? Because it had these paintings on display:

Pierre-Jacques Volaire, The Eruption of Mt. Vesuvius, 1777; from the North Carolina Museum of Art

Joseph Wright of Derby, Vesuvius from Portici, 1774-1776; from the Huntington Library, California

And a copy of this book:

Sir William Hamilton, Campi Phlegraei: Observations on the Volcanos of the Two Sicilies, 1776

For a volcanologist, you can't beat that. I got a few funny looks when I was explaining to my dad why I was so excited about seeing this part of the exhibition, but there were a few smiles in there too. And it isn't every day you get to see such beautiful work that also reflects some of the earliest beginnings of the science of volcanology.

The exhibit will be at the National Gallery until March 22, so if you have a chance to stop by, I would definitely recommend it. (Even though the NGA isn't part of the Smithsonian system, it's still free, so it's affordable even for a poor grad student like me. Unless you give into the temptation of the gelato bar, that is.)

Geoarchaeology: Footprints in ash and the first people in North America

National Geographic News has published an article about the results of new dating methods used on footprints in volcanic ash in Mexico.

The quarry where the footprints were discovered in 2003 is located in Mexico's Valsequillo Basin (and near the Cerro Toluquilla volcano). The footprints were originally dated in 2005, when an international team of geoarchaeologists concluded that the footprints had been created more than 40,000 years ago.

(Image from the NatGeo website, credited to Silvia Gonzalez, Liverpool John Moores University, United Kingdom.)

There seems to be some confusion between various articles about the ash itself - in another 2005 article, the ash is described as being 1.3 M.Y.O. - far too old for anyone to have created the footprints in it while it was still fresh. The new NatGeo article raises this question, but says that "dating the ash is complicated by the fact that an eruption occurred underwater, said Silvia Gonzalez of Liverpool John Moores University, in the United Kingdom." What's strange is that in the Bristol article, the explanation is this:

"The footprints were preserved as trace fossils in volcanic ash along what was once the shoreline of an ancient volcanic lake. Climate variations and the eruption of the Cerro Toluquilla volcano caused lake levels to rise and fall, exposing the Xalnene volcanic ash layer. Early Americans walked across this new shoreline, leaving behind footprints that soon became covered in more ash and lake sediments. The trails became submerged when the water levels rose again, preserving the footprints."

Both quotes were made by Dr. Gonzales, which is somewhat confusing. I don't quite understand why the discrepancy exists, but I suspect that at least one of the articles has fallen victim to some bad editing.

Anyway, the short of all this editing mess is that the 1.3 Ma age is a combination of the age of the ash-producing magma and bedrock pulverized by the eruption. The new study used "optically stimulated luminescence" to determine when the hardened ash was last exposed to sunlight (or volcanic heat), and came up with an age of 40,000 years. Sediment below the ash layer was dated to 70-100,000 years, and above it to 9-40,000 years. This means that the footprints should be at least 40,000 years old, and possibly more, since the ash layer could have sat around for a good long time before being buried by the younger sediments.

I find all this pretty exciting because it has to do with an ongoing (but hopefully dying) debate in the archaeological community about when the first humans arrived in North America. It was a favorite topic of the professor who taught my Intro to Archaeology class, and it's been going on for a good long time now - since the late 1960s, and there are still people arguing about it, although I think the Clovis holdouts pretty much just clinging to dogma by now. "Clovis First" holds that the Clovis people, a Paleoindian culture that first appears in the archaeological record about 13,000 years ago, were the first migrants to the North American continent. The first Clovis points (spear and arrowheads), which have a distinctive "flute" down the center of the point, were discovered in New Mexico in the late 1930s, and have since been found all over North America (and even in parts of Central and northern South America).

For a long time, it was accepted that the Clovis people were the first to show up. Then, in the 1970s, James Adavasio discovered material at the Meadowcroft Rockshelter near Avella, Pennsylvania, that was radiocarbon dated to 16-19 Ka. In 2004, a site in South Carolina called Topper produced charcoal fragments that were radiocarbon dated to 50 Ka, and were interlayered with what appeared to be worked stone tools. There were all sorts of disputes about the accuracy of the carbon dating - some people claimed that the site was contaminated with older material, or that the dating was done incorrectly, or that the charcoal had resulted from natural causes (wildfires or lightning strikes), or that the stone wasn't worked but had been chipped by natural forces.

Other sites (like Monte Verde in Chile, dated to 14.5 Ka) have been discovered that pretty much negate the Clovis First theory, as they change the timing of migrations to North America over the Bering land bridge. (The Clovis people couldn't have been the first over the bridge if the Monte Verde culture, which is more than a thousand years older, made it all the way to South America before the Clovis people did. The Monte Verde research also sparked the theory that the migrations were mainly along coastal waterways, and not limited to land, as had been previously thought.)

The whole thing is a great example of how theories evolve - and it's neat that I can finally use something I picked up in my anthropology minor! (I also think it's pretty cool that the evidence for really old cultures in the Americas is preserved in volcanic ash, but that's just me.)