Indiana Jones and the big-ass disappointment

What a story. Inside one of the most famous tombs in Egypt, archaeologists discover a hidden tunnel carved into the raw stone of a mountain. The tomb of Seti I had been known for over a century when archaeologists discovered the entrance to the tunnel in the 1960s. After removing over three hundred feet of rubble from the tunnel, the diggers gave up without reaching the end or discovering the purpose of the tunnel. It's now fifty years later and the Egyptians are trying again. They have removed another two hundred seventy feet of rubble only to discover that the tunnel leads to... nothing at all. The tunnel, they report, is different that the rest of the tomb. While the tomb of Seti I is famous for its colorful murals, the tunnel is almost devoid of illustration. On of the only inscriptions reads "move the door jamb up and make the passage wider." It took us a half century to discover that the secret of the tunnel is that it is unfinished.


Egyptian antiquities chief Zahi Hawass in the tunnel. Source: National Geographic

Get your Indiana Jones on

Archaeologists are opening a system of secret caves and tunnels under the giant Pyramid of the Sun in Teotihuacan, Mexico. Little is known about the civilization that built Teotihuacan. The city had been long abandoned and overgrown when the Aztecs arrived in the Valley of Mexico. The tunnels were discovered in the 1970s during the installation of a light show for tourists. It was closed soon afterward. Most of the information about the tunnels was lost when Jorge Acosta, the archeologist who excavated them, died in 1976... probably from a curse!

Could anything in archaeology be cooler than finding a secret tunnel under a pyramid? You could drink on that story for the rest of your life.

The secret of Bamiyan

The Taliban's insane destruction of the Bamiyan Buddhas in 2001 may ironically have led to a major historical discovery. Preservationists working at the site since the destruction have discovered the world's oldest oil paintings. In the cliffs behind the now famous nooks where the Buddha statues once stood, monks created monasteries by tunneling and expanding natural caves. These chambers were decorated with religious frescoes that include the oldest known oil paintings in the world. Most art history texts will tell you that oil painting was invented in Renaissance Europe. The paintings in the monks' chambers at Bamiyan are almost one thousand years older.

A combination of synchrotron techniques such as infrared micro-spectroscopy, micro X-ray fluorescence, micro X-ray absorption spectroscopy or micro X-ray diffraction was crucial for the outcome of the work. "On one hand, the paintings are arranged as superposition of multiple layers, which can be very thin. The micrometric beam provided by synchrotron sources was hence essential to analyze separately each of these layers. On the other hand, these paintings are made with inorganic pigments mixed in organic binders, so we needed different techniques to get the full picture" Marine Cotte, a research scientist at CNRS and an ESRF scientific collaborator explains.

The results showed a high diversity of pigments as well as binders and the scientists identified original ingredients and alteration compounds. Apart from oil-based paint layers, some of the layers were made of natural resins, proteins, gums, and, in some cases, a resinous, varnish-like layer. Protein-based material can indicate the use of hide glue or egg. Within the various pigments, the scientists found a high use of lead whites. These lead carbonates were often used, since Antiquity up to modern times, not only in paintings but also in cosmetics as face whiteners.

"This is the earliest clear example of oil paintings in the world, although drying oils were already used by ancient Romans and Egyptians, but only as medicines and cosmetics", explains Yoko Taniguchi, leader of the team.

Due to the large gap of time between the Bamiyan paintings and the Renaissance, it's unlikely that the knowledge of oil painting was transmitted from the East to Europe. It's more likely that it was independently discovered. As Taniguchi says, oil had been used with cosmetic pigments for thousands of years. For most of history, painters have not had access to mass produced or standardized formulas for paints. Each painter had to be an experimenter and chemist with his own secret recipes handed down by their various schools. If pigments mixed with oil were being used for one purpose (cosmetic) I'd expect that oil pigments for painting have been tried and forgotten several times over the millennia.

Hopefully, this will lead to more and better archaeology in Central Asia, one of the least studied parts of the Old World. When I taught a few classes in Ancient History, I was fascinated by the fact that most history concentrates on the outer edge of the Eurasian land mass and ignores the connecting region in the middle. We know that are was active. We know empires rose and fell there. But because of the difficulty of doing work there, the region has barely been studied, and most studies are as an extension of one of the periphery civilizations. There are wonderful things waiting to be found there, but they won't wait. Politics, thoughtless development, fundamentalist thugs, and climate change will destroy libraries worth of knowledge every year unless someone gets there first.

Some pirates are better at plundering than others

Republican state representative Juan Zapata of Florida wants to empty museums and sell off the state's Spanish treasure in order to raise cash and balance the state budget. "We have some interesting goodies in the closet," he explained. "Why not have an interesting garage sale, put them out there and see what we can get for them?" Zapata went so far as to write up his plan, specifying some of the most famous treasure ever recovered in Florida--artifacts from the wreck of the Nuestra Senora de Atocha--as the objects to go on the auction block, and attached the plan to another bill as an amendment.

However, Zapata's plan had to be withdrawn because Florida doesn't own the Atocha artifacts and the real owner isn't planning on donating them to the state. The Secretary of State's office is not enthusiastic about selling the artifacts that they do own. "These are tough times, but we don't sell treasure as a Florida family," said Ryan Wheeler, the state's chief of archaeological research. "We don't sell the family Bible," he added, "or grandmother's china." The Secretary of State's office made no effort to supply Zapata with information about which artifacts they do own.

With bold ideas like that one, Zapata should apply for a job in the Iraqi reconstruction. He could organize a raid on the national museum in Baghdad and sell the loot to private collectors. Oh wait, Donald Rumsfeld already did that.

Nice den for a wolf

Last January I wrote about the possible discovery of the Lupercale, the cave and cult site in ancient Rome where Romulus and Remus were said to have been raised by a wolf. Today, stunning pictures of the mosaics on the grotto ceiling were released by the Italian Ministry of Culture.


So far, no one has entered the sanctuary; all of examinations have been conducted with endoscopes and laser scanners. Much of the grotto is filled with earth and rubble and the original entrance has not yet been located. Irene Iacopi, the archaeologist in charge of the Palatine Hill where the grotto is located, says the team hopes to locate the entrance in new explorations next spring. But even if they do find it, they might not be able to excavate the entrance if it is covered by other valuable ruins. The hill is the oldest part of Rome and hosts, among other things, Rome's first huts from the eighth century BC, a medieval fortress, Renaissance villas, and the Emperor Augustus' palace. These picture might be the closest any of us will get to seeing the site for many years to come.

Two walls

This is a sort of "good news - bad news" story about walls. First the bad news:

A 6.5-metre section of Rome's ancient Aurelian Wall collapsed near the capital's central train station after days of heavy rain, a conservation official said Friday.

The wall, part of a 16th century restoration, crumbled into a pile of bricks Thursday evening after water infiltrated the section, said Paola Virgili, an official in charge of the wall's restoration. No one was reported hurt.

The Aurelian Wall — named after the third century emperor who built it to defend the city against the first barbarian onslaughts — surrounds Rome with more than 17 kilometres of fortifications, towers and gates.

Experts had previously determined that the entire wall section in the area, a 370-metre stretch in the north of the capital, was in danger of collapsing and they had planned to start restoring it Monday.

"It came down before we could even cordon it off," Ms. Virgili said.

At one time I could name most of the Roman emperors up to Constantine. My first thought was that the walls must be named for Marcus Aurelius, even though the century seemed wrong. Actually, the century is right and I'm wrong. The emperor in question is Lucius Domitius Aurelianus (270-75), better known simply as Aurelian. Aurelian began one of the recoveries after a period of civil war and disunion that so often plagued the Roman Empire. The Aurelian Walls are the walls of the city of Rome at it it's greatest as depicted on the maps in many ancient history books. From the story, it appears the city of Rome plans to restore the wall, which is nice, but it would have been nicer if the rain would have held off a few days and they had been allowed to save the walls.

Here's a happier wall story:

A lovely little piece of subway history on the uptown platform of the No. 1 line at 59th Street-Columbus Circle — so old it actually antedates the trains — was concealed from generations of riders by a false wall.

With the false wall being removed as part of the station renovation, history has come to light again: a blue-and-white Art Nouveau plaque, with a flowery border (worthy of willow ware) encircling the words, "The Tiles in This Exhibit are the product of the American Encaustic Tiling Co. Limited / Zanesville Ohio / New-York N.Y."

What exhibit?

It turns out that the 59th Street station was a kind of proving ground for the architects Heins & LaFarge in 1901, three years before the Interborough Rapid Transit Company trains began running through it.

"The architects used its walls as an art gallery, experimenting with decorative ideas in various colors of tiles and other materials," Philip Ashforth Coppola wrote in Silver Connections: A Fresh Perspective on the New York Area Subway Systems (Four Oceans Press, 1984). "When the real decorating of Columbus Circle began, all these preliminary experiments were covered over and forgotten." That is, until this fall.

The transit authorities plan to remove the plaque along with some of the surrounding tiles and move them to the New York Transit Museum. In the mean time, the plaque is there on the wall where it has been for the past 106 years. Only now, any subway rider can view it.

Any city, even a relatively new one, has hidden history and lost treasures. Next time you go downtown in your town, look up above the signs and crowds and take a moment to really see the buildings. You never know what kind of architectural treasures might be hidden in plain sight.

How to read a closed book

I love hearing about new tools and techniques for research. Many areas of science and history can only be expanded by squeezing more information out of the same evidence. Unfortunately, many research techniques are destructive.

For example, Carbon 14 dating requires burning up a sample of the object to be dated. When the technique was first developed, few museums were willing to carve off chunks of their collections to be tested. As a result, it took years to build up a large enough database of tested objects to properly calibrate the technique. This lack of a solid baseline is the reason why so many dates from the early days of C-14 dating have had to be revised, much to the glee of creationists and other C-14 skeptics. Fortunately, as time went by, the technique was improved to need smaller and smaller samples and now the curators of most ancient finds are willing to send in enough material for dating.

Another problem lies in old manuscripts. We all know the scene in the movies where the intrepid archaeologist has just a second to read something before it turns to dust. In real life, this usually occurs when archaeologists or historians try to open a scroll or old book. For a variety of reasons, many old manuscripts cannot be flexed in any way. Sometimes the problem lies in the nature of the paper--papyrus is woven grass and becomes hopelessly brittle. Sometimes the problem lies in what has been done to the paper--iron gall ink, used since the Middle Ages actually burns through the paper. For these reasons, many libraries and museums have collections of scrolls and books that they are afraid to open.

Now the University of Cardiff has come to their rescue. According to a piece on today's BBC, U of C scientists have developed a technique, using their Diamond Sychrotron, that can read manuscripts without opening them. The technique uses a sort of souped up x-ray to find traces of ink in a closed document. The results are then subjected to a computer algorithm which can sort out the different layers and present them for our reading pleasure.

The technique is still in the early stages of development, and a Diamond Sychrotron costs about a half billion dollars, so it's not something your local small college department of library science will be purchasing soon. I also doubt that it will stop archaeologists and historians from wanting to open certain documents. There are many other things to learn from a document than simply what does it say. I expect the early use of the technique will be to establish a backup copy of high value documents, for insurance, before opening them. It will also be useful in deciding which documents are worth the risk of opening. Still, it holds great promise for opening new directions of research. And Diamond Sychrotron is an irresistibly cool name. Look for it show up in forensic cop shows this season.

Of mammoths and cheese

I followed the headline "Ancient Drawing Of Mammoth Found In Cheddar Caves" expecting to find a new and exciting pareidola phenomenon like the Holy Eggplant of Boothwyn, but it's actually a story about a paleolithic drawing in a normal rock cave. Nevertheless, I'm always game for new evidence of our ancestors hanging out with mammoths.

The engraving, which is difficult to see owing to some degradation of the rock surface since the last Ice Age, appears to be an outline drawing of a mammoth made by the addition of what is believed to be humanly engraved lines to some natural features of the rock, a technique which is well-known from the famous French and Spanish decorated caves.

Graham Mullan said: "Unlike our previous finds of abstract designs in the caves in this area, this is a clear representation of an animal. We are more confident that at least part of it was humanly made and the subject material places it firmly in the latter part of the last Ice Age. Finds of mammoth ivory of that age have been made in this cave in the past indicating that these animals would have been known to the inhabitants.

"Although the cave has been studied by many archaeologists, this engraving has previously escaped notice because it is quite difficult to make out. For this reason, a careful study has been made and this announcement was delayed until we were reasonably confident of the attribution."

[...]

Jill Cook, Deputy Keeper in the Department said: "Had I been shown this outline of a mammoth during a visit to one of the well known cave art sites in France or Spain, I would have nodded and been able to accept it in the context of other more obvious pictures. At Gough’s, or anywhere in England, it is not so easy. Cave art is so rare here that we must always question and test to make sure we are getting it right."

In the photograph accompanying the article, I'm not sure which curve is supposed to be the mammoth. I can point to two possibilities. I hope that it's more obvious to those actually present, or else we might be dealing with nothing more than wishful thinking pareidola, much like Jack Cuozzo's drawing of battling mammoths and dinosaurs.

But probability is on their side. Cheddar is one of the richest archaeological areas in Britain and is home to Cheddar Man, the oldest complete human skeleton so far discovered in the British Isles, and other signs of human habitation back to the end of the last ice age. It's also home to sites from the Saxon and Roman settlements as well as megaliths.

As any student of British archaeology knows, wherever there are megaliths, there will also be students of Atlantean Ley lines and other archaeological woo. Cheddar is no different in this respect. So maybe there will be a British Jack Cuozzo to give their new mammoth the cheesy over-interpretation it deserves.

More mammoth news

We have another new study that weighs in on the mystery of mammoth extinction this week. I wish this story had come out about four days earlier so I could have included it in my last big mammoth post. Just in case you were laying awake at nights wondering if the entire world was organized for John's convenience, this is a vote in the "NO" column. Sigh.

Some ancient-DNA evidence has offered new clues to a very cold case: the disappearance of the last woolly mammoths, one of the most iconic of all Ice Age giants, according to a recent article.

Get it: "cold case, Ice Age?" These folks are clearly crowding in on my act.

DNA lifted from the bones, teeth, and tusks of the extinct mammoths revealed a "genetic signature" of a range expansion after the last interglacial period. After the mammoths' migration, the population apparently leveled off, and one of two lineages died out.

"In combination with the results on other species, a picture is emerging of extinction not as a sudden event at the end of the last ice age, but as a piecemeal process over tens of thousands of years involving progressive loss of genetic diversity," said Dr. Ian Barnes, of Royal Holloway, University of London. "For the mammoth, this seems much more likely to have been driven by environmental rather than human causes, even if humans might have been responsible for killing off the small, terminal populations that were left."

Besides its intrinsic interest, the end ice age extinctions are important to paleontologists for the simple reason that we have more information about this extinction event than any other. Both because it was so recent and because we are still in the Pleistocene Ice Epoch, many of the extinct animal remains that we have to examine are not yey fossilized. We have actual soft tissue of hair, skin, bone marrow, internal organs, and, most importantly, we have DNA. We know more about mammoths than any extinct animal outside those that we are currently in the process of driving extinct.

This sort of genetic diversity study is an example of the kind of work that we can do on the end ice age extinction event that we can't do on, for example, the much more popular K-T event which killed the dinosaurs. Because we can study this kind of detail about this event, it has a special importance as a test case for any broad generalization that anyone makes about extinction.

This study has an impressive list of co-authors, including Adrian Lister of the University College London and the Natural History Museum in London, a major authority on things mammothy, and R. Dale Guthrie University of Alaska in Fairbanks, the primary spokesman for the climate model of end ice age extinctions.
In the name of full disclosure (or bragging), my number one sister works for the University of Alaska system and has participated on an important dig with Prof. Guthrie.

A limitation to this study is that it primarily focussed on Siberian mammoths (the region from whence we get most of our best mammoth remains). Any conclusions they draw must be qualified by that limitation. However, like the Kennett study and the Last study, this sort of work piecing together the regional details of the transition from the last ice age into the current interglacial is relevant today in understanding major climate change and especially exciting to me, just because.

A new narrative of mammoth extinction?

A new theory of mammoth extinction was proposed by James Kennett, of the University of California in Santa Barbara, at the annual meeting of the American Geophysical Union two weeks ago in Acapulco. Predictably, it involves comets.

Why predictably? Scientific theories have a special rhythm of their own. As intellectual constructs they are not completely neutral, objective formulations. Theories are as dependent on the intellectual climate that produces them as any type of creative work is. The ideal of scientists gathering all of the facts and developing theories based on what the facts tell them is just that: an ideal. It's not real. This doesn't mean scientific theories are as shallow and prone to silly fads as, say, teenage clothing fashions. Let's say that they are much deeper and prone to trends, not fads. At the very least, the intellectual atmosphere of the day decides what the questions are that scientists are trying to answer when they set out to gather "all of the facts."

For example, the question of what caused the mammoths to go extinct would not have occurred to thinkers at the beginning of the Enlightenment. At that time, no one believed extinction was even possible. It went against all common sense, they thought. Look at the difficulty of the task. How could every single member of a species be killed? Even the most virulent plague leaves a few survivors. The greatest hunter can only kill a limited number of prey each day. As he kills, the other prey are warned and flee before his approach. Besides, the world is an enormous place. Even if we were to kill all of a species over here, there will always be survivors somewhere else. Look at the wolf. Europeans had been trying to kill off the wolf since the beginnings of history, but there always more wolves lurking around the edges of civilization.

No, the wise men of the day said, shaking their wise heads, it’s just not possible. Being wise people, they didn’t depend on mere common sense to back up their position--after all, common sense is so, well, common. They had the authority of ancient thinkers and God himself to back up their position.

For those of a philosophical bent, Aristotle's doctrine of plenitude, as interpreted through the lens of seventeen centuries of Christianity, provided the key argument against extinction. The doctrine of plenitude, or the fullness of the natural world, argued that any life form conceived by God must have come into existence as part of his perfect world. Each part of creation is necessary for creation's divine perfection as a manifestation of God's perfect mind. No life form created by God could ever cease to exist, because that would leave an unbridgeable void in the Great Chain of Being. For those more inclined to eschew philosophy and take comfort in a good Biblical verse, there was Ecclesiastes 3:14 -15: "I know that, whatsoever God doeth, it shall be for ever: nothing can be put to it, nor any thing taken from it.... That which hath been is now; and that which is to be hath already been; and God requireth that which is past." In either case, extinction just couldn't be.

When Enlightenment thinkers accepted fossils as the remains of once living things and not just interesting rocks that happened to look like bones or shells, they first tried to make all fossils the remains of known animals. When some fossils were proven to be unfamiliar species--most importantly, Georges Cuvier proving that mammoths were not the same as modern elephants--they argued that these animals must now live in still unexplored regions of the earth. Catherine the Great and Thomas Jefferson, two of the best-informed leaders of the day, both believed that mammoths and mastodons existed on the distant frontiers of their respective countries. But others found the idea that such large land animals could stay hidden highly unlikely. Through the early years of the nineteenth century, the idea of extinction gradually gained acceptance.

The idea of extinction wasn't pushed through by sheer force of the evidence. Other successful ideas helped make it more acceptable. From the earliest days of the Renaissance, European thinkers had had to deal with the fact that the world was a lot bigger and more complex than they had ever imagined. This raised many difficult questions about the literal truth of the first chapters of Genesis. The questions themselves were only very cautiously voiced. The one implication of this questioning that remained unvoiced the longest was the idea that the earth must be much older than mentioned in Genesis in order to account for the size and complexity of the new universe.

Medieval thinkers had never lost sight of the fact the fact that the ancients had believed the earth to be either eternal or subject to eternal cycles of creation and destruction. For a millennium, it was possible to mock such ideas as a sign of unenlightened ignorance. However, after Magellan and Copernicus expanded the known universe, it made sense that more time went hand in hand with more space and more complexity.

More time meant more room for vast changes in nature to develop, either gradually or in forgotten upheavals. This made extinction easier to accept as a part of the greater whole. Additionally, at the same time extinction was gaining acceptance, the idea of ice ages was suggested by Louis Agassiz and quickly gained acceptance. Two years after Cuvier announced his conclusion that the mammoth was an unknown and extinct type of elephant, the first frozen mammoth, that would be recovered and brought back to Europe, was found in Siberia. This showed that the mysterious elephants of Europe and Asia were great hairy beasts more suited to extreme cold than to temperate climates. Again, each idea helped gain acceptance for the other. The idea that the mammoth was a creature adapted to the frozen wastes, who perished when the earth warmed, formed a perfectly suitable narrative for the emerging ideas of the history of the earth.*

This was the first coherent, scientific theory of extinction for the mammoth.** It was a perfect narrative for the nineteenth century. It emphasized the treacherous and dangerous side of nature. Despite forays into sentimental romanticizing of nature, nineteenth century Western culture basically saw nature as something to be fought and tamed. Mankind's ability to change and adapt was seen as progress, a virtue. Our technology gave us the ability to change nature to fit our needs, rather than changing ourselves as nature demanded. The poor mammoth was at the mercy of nature's capricious changes and died out. This extinction narrative would remain unchallenged for over a century.

By the late 1940s, faith in the positive character of technology, the inevitability of progress, and mankind's ability to survive had all taken a blow. The holocaust and the atomic bomb brought on a crisis of self-doubt. Artists and mainstream intellectuals seriously considered the possibility that mankind's innovation might be the source of our own imminent extinction. In 1961, Robert Ardrey published African Genesis, a new narrative of human evolution that emphasized man the hunter, not in its previous heroic mold, but as a vicious carnivore with an instinct to kill and destroy. The next year Rachel Carson published Silent Spring, a book that documented the unexpected negative consequences of indiscriminate pesticide use and which became one of the seminal documents of the environmental movement. Both books were controversial bestsellers and widely discussed for the rest of the decade. The next scientific theory of mammoth extinction reflected these new, pessimistic assumptions of the post war world.

Paul Martin, in a series of papers published in the mid-sixties, argued that mankind and our technology were the cause of the extinction of the mammoths and other large mammals at the end of the ice age. The theory was not entirely new, Cuvier's contemporary Lamarck had believed it, but, it had never had strong evidence to support it. Though there was evidence that people had lived with and hunted mammoths in the Old World, the first evidence that humans and mammoths had lived together in the New World wasn't known until 1929 and the excavations at Clovis, CO. The first iron-clad proof of a mammoth kill in the New World wasn't discovered until 1953 when a mammoth with spear tips between the bones was found at Naco, AZ.

Martin's 1967 paper pulled together a wide array of radiocarbon dates to show that the mammoths and other large ice age mammals all went extinct within about one thousand years of the earliest evidence of humans in the New World (the Clovis site). To add to his argument that humans caused extinctions, he demonstrated the same pattern of human arrival and large animal extinction in Australia, Madagascar, and the Pacific Islands. Martin has a flair for language; he called his theory the Overkill Hypothesis, referred to a blitzkrieg of hunters advancing through the New World, and said, "large mammals disappeared not because they lost their food supply, but because they became one." His presentation was very appealing in a melodramatic decade and soon had many followers.

For the next thirty years the climate and overkill theories battled it out until a third theory appeared suddenly in 1997. In the age of AIDS, it was perhaps inevitable that the someone would suggest a plague as the killer of the mammoths. Ross MacPhee, of the American Museum of Natural History in New York, suggested the possibility of a plague carried by humans or their dogs into the New World killing most of the big game before they could hunt it and forcing the hunters to settle down and become farmers or to change over to smaller game. MacPhee has yet to find any direct evidence to support his theory but gathers samples from each new frozen mammoth discovered to see if it contains any unknown pathogens.

Now we have comets. Like disease and a suspicion of technology, comets have been in the air lately.*** Comets or meteors were an early suspect for the extinction of the dinosaurs, but not a favored one. The preferred idea was that dinosaurs were done in by a combination of climate change and swift mammals.

The leading interpretation of meteors was that most of the big ones were used up in the early days of the universe and that the odds of a dangerous one hitting the earth were, well, astronomical. The unfortunate affair of Velikovsky's cosmic billiards theory of ancient history had further soured most scientists on crediting meteors or comets with causing anything. This changed in 1980 when Luis Alvarez, his father and two chemists published clear evidence of a large cosmic event of some sort happening right at the K-T boundary, the border between the last rocks containing dinosaur fossils and the first without.

The Alvarez theory was hotly debated all through the eighties. Because of the popularity of dinosaurs with children, the debate was more widely known by the public than most scientific disputes. Many scientists specializing in other periods of mass extinction reviewed their evidence to see if other meteors were possible. Some even thought they saw a periodic pattern of meteors and extinctions every twenty six million years. By 1991, David Raup, possibly the leading expert on all extinctions, could wonder in print, "could all extinctions be caused by meteorite impact?" The Alvarez theory is still disputed, though the number of disputants was reduced dramatically at the end of the eighties when a 300 kilometer wide crater of the right age was revealed to lie beneath the Yucatan peninsula.

Other events in the eighties and nineties kept the possibility of cosmic impact on the public mind. Halley's Comet returned in 1986. The spectacular impact of the fragments of Comet Schumacher-Levy 9 with Jupiter in 1993 was the first time a large planetary impact was directly observed and studied by human scientists. This was followed by a couple of big budget summer movies featuring giant impacts.

That an idea is fashionable or rooted on contemporary social concerns and attitudes does not necessarily mean that it is wrong. Though it does mean that Kennett's theory will almost certainly face extra scrutiny. That's probably a good thing. Fortunately, Kennett has evidence:

Evidence for the impact comes from a thin layer of sediment found throughout North America, said James Kennett, a geologist at the University of California in Santa Barbara.

"There are materials with particular chemistries in that layer that collectively provide very strong evidence that the layer was produced by this extraterrestrial impact," he said in a telephone interview.

Kennett said the layer contains tiny spheres of carbon and metals, bits of diamonds, and extraterrestrial concentrations of helium 3 and the element iridium.

The layer dates to 12,900 years ago, he added.

At about the same time, according to the researchers, Earth's climate cooled; mammals like mammoths, mastodons, and saber-toothed cats went extinct; and one of the first American cultures disappeared.

Kennett has a very specific series of events in mind and this leaves many point that can be tested by experts in a variety of fields.

First, he pictures his impact appearing somewhere near the Great Lakes. Naturally, geoleogists will search for more debris from the impact in that area to see if his distribution is correct. Was there really an event centered in that area? If so is there a crater. There doesn't have to be a crater. It could be that the impactor exploded in the atmosphere or that it hit the glacial ice shield, which at that time was just north of there draining into the lakes.

Kennett says the impact would have released a great amount of cold meltwater into the Atlantic, possibly changing the global climate for decades. This theory is already widely accepted. At the time he mentions, the end ice age warming was suddenly reversed in an event called the Younger Dryas. The cold water flood is the most often named cause for the Younger Dryas. Even if Kennett's comet is proven, it must match the date of the Younger Dryas for his scenario to work.

Third, he has thrown himself right into the middle of the climate versus hunting controversy over mammoth extinction. While the impact itself might have been a cause of regional extinction for the mammoths through forest fires and direct devastation of their habitat, it is abrupt climate change of the Younger Dryas that has to do in mammoths and other large mammals in places like South America (where three genera of mastodon-like gomphotheres went extinct).

The fourth and last element of his theory is the newest and perhaps the most interesting. Kennett and his son Douglas Kennett, an archaeologist at the University of Oregon in Eugene, claim that the comet was a major cause of the end of the Clovis culture. The extinction of main big game prey has been the main theory given for the abrupt end of the Clovis culture. This theory works whether they caused the extinction through over hunting, by bringing a plague, or just had the bad luck to arrive as the climate killed all the big game. Losing their prey would have forced a change of lifestyle on the Clovis.

The Kennetts suggest two related but different causes for the end of Clovis culture in different regions. In the West and in what's now Latin America, the Clovis culture died out after losing their prey. But in the East, especially around the Great Lakes, the Kennetts point to an apparent gap between the end of Clovis culture and the beginning of post Clovis culture. They suggest that the impact really did wipe out most life in the area. In their narrative, forest fires, devastated habitat, and fallout killed or drove away all of the people in the East. It was only after the Western Clovis has diversified into new cultures and the Eastern forests grew back that humans recolonized the region.

I'm eager to see what happens when others go over the Kennetts' evidence. The story of the extinction of the mammoths and other large mammals at the end of the last ice age, the arrival of humans in the New World, and the transformation of the environment of the Americas is one of the great mysteries of the historical and earth sciences. So too is finding the right place for cosmic impacts in the history of the earth and its life. Whether the Kennetts' theory survives or not, the discussion should be fun.

* At the same time a counter idea grew up that the mammoth was a creature of a slightly colder time before the ice age who perished when it got too cold. This idea has never had large scale support but has never quite gone away either.

** The religious ideas that extinct species are the remains of prior creations--God using the earth for other projects before man--or that they perished in the flood have always been problematic because they are not mentioned in the Bible. The previous creations idea depends on the possibility of an unmentioned gap of time between God creating the heavens and the earth and the first day of Genesis. The idea that species were killed in the flood directly contradicts God ordering Noah to gather two of every animal and Noah fulfilling God's will.

*** Sorry, I couldn't resist.

Looking for drowned mammoths

A series of enormous prehistoric floods that killed hundreds of innocent mammoths have been the subject of increased scientific and political attention this spring. The floods, known as the Glacial Lake Missoula, or Bretz, Floods, occurred twelve to sixteen thousand years ago at the end of the last ice age. They were among the largest floods known to geologic history and shaped much of the landscape of Eastern Washington. They were also incredibly cool.

Last week, Coturnix pointed me toward the following news release. It has mammoths, he said, I should comment on it.

Pacific Northwest National Laboratory geologists have put out a call for teeth, tusks, femurs and any and all other parts of extinct mammoths left by massive Ice Age floods in southeastern Washington.

The fossils, in some cases whole skeletons of Mammathus columbi, the Columbian mammoth, were deposited in the hillsides of what are now the Yakima, Columbia and Walla Walla valleys in southeastern Washington, where the elephantine corpses came to rest as water receded from the temporary but repeatedly formed ancient Lake Lewis. PNNL geologists are plotting the deposits to reconstruct the high-water marks of many of the floods, the last of which occurred as recently as 12,000 to 15,000 years ago.

"Now is the perfect time to collect geologic and paleontologic data," said George Last, a senior research scientist at the Department of Energy laboratory in Richland, Wash., whose sideline is researching the ice-age floods. "Winter has eroded the slopes, exposing new evidence. We're interested in researching any known or suspected mammoth find, to collect additional evidence and to improve documentation of those sites."

This is more than a story about mammoths, it actually a story which combines several of my interests. Naturally, the fate of the mammoths is number one, but the Bretz floods are a close second. The Northwest has a fascinating geologic history and the floods are one of the most dramatic. I hope to make a couple of road trips this summer to look at, and blog about, some of the special topics in this story, but today I'll just mention the link between the floods and the mammoths.

The story begins just before the end of the last ice age. Obviously, the climate of North America was radically different at that time. Most of Canada was covered by ice sheets. The eastern and middle parts of Canada were covered by the Laurentian Ice Sheet, which was centered what is now Hudson Bay. In the west was the Cordilleran Ice Sheet, centered on the western mountains. While the Laurentian Ice Sheet crossed the Great Lakes and reached to about the line of the Ohio River, the Cordilleran Ice Sheet barely crossed the Canadian border to cover a sliver of northern Washington, Idaho, and Montana.

The western part of Montana, between the Continental Divide on the crest of the Rockies and the Idaho state line on the crest of the Bitterroot Mountains--an area about the size of West Virginia--is drained by the Clark Fork River. Unlike most rivers in the United States, the Clark Fork flows north. It loops across the Idaho panhandle near the Canadian border and joins the Columbia River in the extreme northeastern corner of Washington. At the end of the last ice age, the Cordilleran Ice Sheet made a sudden lurch southward. A branch of the ice sheet called the Purcell Lobe pushed into Idaho near the location of the present day town of Sandpoint and blocked the Clark Fork. Behind the Purcell Lobe all of the drainage of the Clark Fork was damned up, eventually to form a Great Lake sized body of water called Glacial Lake Missoula. When the lake was full, the future location of the town of Missoula was beneath a thousand feet of water.

Because ice is lighter than water, an ice dam must be about ten percent higher than the water behind it to be stable. When the water that had been gathering behind the Purcell Lobe began to approach the top of the glacier, the situation became unstable. That situation was reached when the water was almost two thousand feet deep at the dam. The pressure at the bottom of the dam was enough for lake water to force its way under the glacier. The water then floated the southern tip of the Purcell Lobe and began to rush out under it. Within a few hours time, the glacial dam collapsed and was torn apart by the rushing water.

A wall of water almost a half mile high blasted out of the mountains into Eastern Washington. These are the floods. I call them the Bretz floods after their discoverer, J Harlan Bretz (the J doesn't stand for anything; Bretz's parents were too poor to afford a first name for him, so he only got a letter). Other writers call them the Glacial Lake Missoula floods after their source. Still others have other names. In any case they are among the largest floods in known geologic history and the most dramatic event in recent Northwest geology.

Most of Eastern Washington is a plateau formed by enormous volcanic basalt flows formed over ten million years ago. The Columbia River flows in a large loop around the northern and western sides of this plateau. During the ice ages a fine dust, churned up by glaciers in the Cascade Mountains had covered this plateau with an deep, rich topsoil. When watered properly, this land is incredibly fertile. Even in the close proximity of the Cordilleran Ice Sheet it would have presented an irresistibly attractive feedlot for grazing and browsing animals. Animals like mammoths and mastodons.

When the waters of Lake Missoula blasted into Eastern Washington, they skipped the loop of the Columbia and traveled across the plateau. The flood tore up entire counties worth of topsoil and carried it away. It deposited enormous gravel bars. It changed the course of rivers. It carved massive canyons in areas that are now desert. It drilled lake-sized holes deep into the basalt bedrock.

In places the flood is believed to have passed as a five hundred foot high wall of muddy water traveling at up to one hundred miles per hour. It pushed hurricane force winds ahead of it. The water itself was a churning brown mass the color and texture of a runny chocolate milkshake. It carried with it topsoil, rocks, trees, entire herds of mammoths, and the icebergs that had formerly been part of the Purcell Lobe. For two weeks, the Columbia carried several times more water than all the rivers in the world combined.

Where the flood ran into narrows, it backed up to form gigantic temporary lakes. These lakes backed up side valleys and there, when the water slowed down, it deposited some of its load of soil and rocks. The topsoil of Eastern Washington has made the valleys of the Yakima, Walla Walla, and Willamette some of the most productive agricultural area in North America, especially for wine. Geologists have named each of these temporary lakes.

The greatest of these stoppages happened at the point where the Columbia River leaves Eastern Washington and turns due West to form the Washington-Oregon state line. At this point, the Columbia passes through a gap in the Horse Heaven Hills. This gap--the Wallua Gap--is about a mile wide and a thousand feet deep. The floodwaters were so vast that they found this gap much too small to pass through. They backed up and overflowed the hills to either side of the gap. Channels carved into the top of the ridge testify to this. The lake that backed up into Eastern Washington is called Lake Lewis. This is the lake that Dr. Last has been studying.

In this map, the light blue shows the furthest extent that the Cordilleran Ice Sheet reached about sixteen thousand years ago. Glacial Lake Missoula is the dark blue area on the left. The Purcell Lobe ice dam is marked by a yellow dot. The dark blue in the center is another ice-dammed lake called Glacial Lake Columbia. The floodwaters from Lake Missoula entered Lake Columbia near the present day site of the city of Spokane and immediately overflowed Lake Columbia's southern banks. The brown area in the center of the map is Lake Lewis formed by floodwaters backing up behind Wallua Gap. The gray area between Lake Columbia and Lake Lewis is the area torn up by the escaping Lake Missoula floodwaters, an area called the channeled scablands. The gray areas below Lake Lewis are the subsequent lakes formed as the flood moved on to the sea. Notice haw far the flood backed up the Willamette River valley into Oregon. (Map source)

Although Lake Lewis only lasted for a few days, it slowed the floodwaters long enough for some of the matter churned up and animals killed to settle out. What's more, the rapid silting buried the dead animals in conditions almost custom made for fossil preservation. It is this bathtub ring of fossils that Last hopes to study.

The Lake Missoula flood wasn't a singular event. After the waters rushed out, the Purcell Lobe pushed forward and blocked the Clark Fork valley again. The river backed up and formed a new lake. After forty or fifty years, it was deep enough to float the glacier again and flood the Columbia again. This cycle dominated the Columbia valley for over two thousand years. There is sedimentary evidence of between forty-one and eighty-nine floods, although at least two came from lakes other than Lake Missoula. Midway through the floods, Mt. St. Hellens was good enough to erupt and lay down a layer of isotope rich and easily dated ash to help geologists understand the sequence of the floods.

Last summer when I added the Bretz floods to my short list of current obsessions I immediately wondered how the floods might have affected the northwest mammoth populations. The first flood would have wiped out almost all of the mammoth population in the plateau and lower reaches of the Columbia River. With subsequent floods coming every forty years or so and mammoths having a very slow period of natural increase, I wondered if the population would ever have recovered. On the other hand, a few years after each flood, those valleys must have been filled with tender young trees and brush, which would have made them terribly attractive to grazers and browsers from surrounding areas, especially in Eastern Oregon, which is a continuation of the same plateau and would have hosted the same wildlife. That growth would have had the effect of luring the mammoths and mastodons back in just in time for the next killing flood, extending the population impact over a much larger area than that of just the flooded valleys. The floods must have had a major influence on wildlife populations all over the Northwest.

George Last tells me that these are exactly the questions he is trying to answer. I'm glad. I think that there is a lot to be learned from reconstructing the geologic and environmental history of the Northwest. Fifteen thousand years ago this region went through a brutal environmental change. The floods were only one part of a major climate shift that accompanied the end of the ice age. Over the next century the Northwest will go through another major change. That process of change began about two centuries ago when Europeans began to settle here, to place new stressed on the plant and animal resources, and to introduce new species into the local environment. Climate change is the latest phase of pressure that we have brought, but it is only part of the story. By understanding how the local environment responded to past changes we might better respond to future ones. Or not. At least by collecting all of the data we can, we'll have a good chance of managing the current one intelligently.

Last and I are not alone in hoping to increase awareness of the Bretz Floods. The Ice Age Floods Institute, with chapters in Washington, Oregon, Idaho, and Montana has been lobbying Congress for years to recognize the flood region as a significant part of the nation's, and the world's, natural heritage. Their main priority has been to get the Park Service to establish a system of official trails to protect key locations and create educational signage along six hundred miles of trails stretching from Montana to the coast. The trail plan only affects land already in the public domain; it does not seize any private land. The plan would cost eight to twelve million to establish the system, which is chickenfeed compared to many government projects. Last is an important member of the institute; I would be a member too, but I'm not joining anything until I get a job.

It's an idea whose time seems to have come. A number of trail guides have appeared in recent years that tell the story of the floods and guide hikers to some of more interesting artifacts of its passage, like giant erratic boulders and mysteriously dry waterfalls in the desert. Nova filmed an episode about the floods back in 1979 and has recently rerun it and released it on DVD. A collapsing ice dam and endangered mammoths were the main plot of the animated movie Ice Age 2.

To establish the trail, both houses of Congress need to pass identical bills creating the system. During the last session of Congress, similar bills were passed in both houses, but Congress adjourned before a compromise bill could be agreed on. This year, identical bills were introduced in both houses--eliminating the need for a conference bill--and the Senate bill made it out of committee, but so far neither bill has made it to the floor for a vote. It has the support of the leading Democrats and Republicans in the Washington delegation as well as members of the Idaho, Oregon, and Montana delegations. The bills are and S 268 and HR 450 both entitled To designate the Ice Age Floods National Geologic Trail, and for other purposes.

This might not sound like the most important use of your activist energies, but, like piecing together the past, it's all part of a bigger picture. In this case, the trails are part of the educational side of the program. If you love mammoths, you'll write to your congresscritters and demand that they push this one through. And, if you happen to be passing through Eastern Washington and notice a dead mammoth by the side of the road, be sure to give Last a call.

Correction - George Last wrote to me point out that I had misidentified his title. He's not a Doctor, but he does have a Master's degree in Environmental Science (Hydrogeology Option). Sadly, there is no title for those of us with "just" Master's degrees. I once pushed for "Magister," a title that is still used in some European academic systems, as the best candidate. But, like most of my language suggestions, this one has not gained much traction.

Built to last

Here's a nice story about a new archaeological find in Greece. It's on the island of Kefalonia, which is on the west side of Greece facing the heel of the Italian boot.

Archaeologists on a Greek island have discovered a large Roman-era tomb containing gold jewelry, pottery and bronze offerings, officials said Wednesday.

[...]

The complex, measuring 8 by 6 meters (26 by 20 feet), had been missed by grave-robbers, the announcement said.

Archaeologists found gold earrings and rings, gold leaves that may have been attached to ceremonial clothing, as well as glass and clay pots, bronze artifacts decorated with masks, a bronze lock and copper coins.

The vaulted grave, a house-shaped structure, had a small stone door that still works perfectly -- turning on stone pivots.

I'm not sure why they sound surprised at that last bit. Don't these people watch movies? Stone doors in ancient tombs always open easily. I think it's a law. It doesn't matter if the door is Roman, Egyptian, Aztec, or Atlantean; all you need is the sacred brooch, which functions as a key, and the door opens automatically. You don't even need WD-40.

I have a theory about these locks and hinges that don't corrode or even get clogged with dust over thousands of years. They were actually the cause of the collapse of ancient civilization. Once they had perfected small mechanical things like this and installed them in their tombs, along with fiendish death traps, they couldn't get any repeat business and their economy collapsed. Fortunately, we've perfected built-in obsolescence, so our civilization will last forever (or until the giant squid discover fire).