Saturday, June 27, 2009

Schwäbisch-Fränkischen Alb: Little teeth and my European Ancestors

Since Germany was underwater for most of the Age of Dinosaurs (The Mesozoic Era), there is plenty of limestone underneath the country (limestone forms exclusively in aquatic settings where there are lots of little organisms generating calcite for their skeletons). When limestone is taken above the water line, it’s quickly dissolved (geologically quickly, I guess) by slightly acidic groundwater. These dissolved cavities are then called caves, as in stalactite bearing, blind fish holding caves. With all that limestone and all those cavities, much of Southern Germany is prime cave country. When caves open up, animals and sediment tend to fill the void. Our expedition moved into the Schwäbisch-Fränkischen Alb, a mountain range composed entirely of Mesozoic limestone to visit some of these cave sites where younger fossils have piled up as caves opened in the rock and local critters fell in, creating a tangled geological history for the region.

These cave fills are often the best source of fossils for terrestrial ecosystems since the caves create sink holes in the middle of the forest and animals who wouldn’t normally get deposited in a lake (rodents, monkeys, lizards etc.) get swept into the cave. One cave-fill contained rocks that were almost entirely composted of bones and teeth that were cemented together by the calcite that had seeped out of the cave walls (the same calcite that grows into beautiful cave forations):

Another cave was a chimney-like shaft where we sifted through sand for Oligocene teeth and bones. It’s always gratifying to collect where you actually find vertebrate bone (assuming you’re a vertebrate paleontologist). That site was especially exciting because it required some careful scrambling through briars and over outcropped rock. A cliff face and rock ledge will always make a geological expedition more fun.

We also examined a cave that hasn’t been filled in yet. It formed underground like a rocky bubble and lay unexposed for millennia until the surrounding rock finally winnowed away leaving a chamber just big enough for a family and the kids. And that’s exactly what it was used for. Cro-Magnon people (early modern humans) rolled into the area and liked the view overlooking the entire basin. It was probably a good spot to watch for mammoths, and even better for watching the sunset.

We ate lunch on the crest of a hill near the Cro-Magnon cave. Boulders protruded from the field of lush grass and wildflowers creating a gorgeous landscape in want of a henge or barrow. I dangled my feet over the edge of a boulder.

To my left was another hill and another outcrop where excavators had found a butchered wooly rhino skeleton from the Paleolithic (50,000 years ago), and a small encampment from the Neolithic (10,000 years ago). Mesozoic rocks, Oligocene fossils, human artifacts…this is Germany. This is why I came here.

We also stopped by a 15 million year old impact crater. When large rocks smack into the earth, the bedrock ripples like the surface of a pond, mixing up the layers and leaving an uplifted central platform; the earth’s frozen rebound to the power of the asteroid. The crater quickly filled with water and became a popular place to stop for a drink when horses were still sporting three toes.
A museum reconstruciton of Steinheim 15 million years ago.

The town of Steinheimer is nestled into the bowel now, sitting on top of a thick sequence of lake sediment. An observant Steinheimer scientist named Hilgendorf started to pay attention to the snail shells that were preserved under his feet. As he burrowed deeper, he noticed the shells were more standardized, more basic. By collecting shells from the beginning of the lake to the end, he demonstrated how one colonizing species gave rise to new species of snails through intermediary steps. He published his work in 1862 and is credited as being the first scientist to demonstrate Mr. Darwin’s crazy new theory of change through time and the emergence of speices. I collected some of those snails out of historical respect more than out of a need to add more mollusks to my luggage.
The classic branching of speciees outlined by Hilgendorf a few years after Mr. Darwin published his bright idea.

The sediment that holds the snails. All those little white dots are tiny freshwater snail shells.

That night we stayed in Sigmaringen, a Baverian town near the source of the Elbe River which eventually runs through Dresden, Prague, and Vienna. We walked to dinner, dodging past the massive slugs and even more massive snails that come out with the rain. (The snails are large enough to double as speed bumps for the absent-minded cyclist.) We crossed a modern bridge that looped over the road, rounded a bend and, as is want to happen in Europe, we were confronted with a castle. The massive Renaissance structure was built by a German lord in the 16th century. Of course, I didn’t have my camera on me so you’ll have to make due with these images borrowed from Sigmaringen’s tourism website.

This image of the castle is just too epic to let sit on only one website.

At a traditional inn next to the castle, we toasted the final night of the expedition with delicious Heles beer and happily stumbled home.
On the distant horizon you can see the Swiss Alps rearing their beautiful heads. I'm standing on a crater rim by the by.

Our final field stop was to another crater lake that was formed in an ancient volcanic crater. The animals were mostly early, mid-sized horses, but a few rhinos, and the odd beardog, the ancient relative of both carnivores, spiced up the fauna a bit. The site was introduced to us by a professor of geology at the university in the region. He struck me as a down-to-Earth (pun intended) hippie who just loves fossils, man. His beard was growing wild, his hair fell lower than his shoulders, and he seemed to prefer going barefoot. His lead excavator was the polar opposite. He was a good ol’ boy with a thick regional accent and a need to carefully explain every detail in a methodical drawl. His galoshes hiked up to his knees, and his upper lip hiked up to a large, well-groomed mustache. The two men have been working together for at least a decade, but I imagine most of their conversations come straight out of “The Odd Couple.”
A toe quiz. I rocked this one. Do you know which critters are on display here? Hint, they have hooves and are distantly related to each other by having odd numbers of toes.

And north we rode. I discussed American and German movies with my increasingly friendly seatmate and actually delicately touched on German between 1930 and 1945 with some frankness. And thus the Fulbright mission goes on.

After returning from the field I diligently worked on my fossils, attended a lecture on Creationism given by an angry Australian Geologist (more on that next week after I give my own talk on the history of American Creationism), and went to visit Marco for Japan Tag (Japan Day), a celebration of Düsseldorf’s Japanese population with heaps of street sushi, noodles, and Kirin Beer. The streets were packed with Germans demonstrating karate and dressed as their favorite Anime character in a mini-skirt. The night was rounded off with the largest fireworks display in Düsseldorf, which was vaguely disappointing after years spent at Riverfest and the Blue Ash Fireworks displays. Germany may have cavemen, but it doesn’t make things explode into brilliant colors quite like we do at home.

I hope you had a fantastic weekend and are mentally prepared for the coming week. I’m just getting back into town after a tour of Switzerland, the Rhineland, the Low Countries, and England with friends from Ohio State. Stay tuned for adventures such as cycling in Amsterdam, climbing in the Alps, and theater gooning in the West End!

No comments: