sjudge August 9th, 2010
Guest Blogger: Jesse Davenport
That is, when you look outside all you see is sky for miles upon miles upon miles upon…well you get the picture. It is extremely beautiful here. In Island Park, Idaho, we are sitting right on the border of Montana. Yellowstone is just a mere 30 miles away. It is one thing to read and study an area like I did for my junior thesis, but is an entirely different to actually be able to see the areas that I read about.
After a shaky first two days of traveling arrangements at the lovely Bozeman airport, everyone was finally together. Everyone including me, Caleb Lucy from Williams College, Danielle Lerner from Mt. Holyoke, Kristina Doyle from Amherst, Parker Haynes from the University of North Carolina, and Ali Walker from Smith College. And of course our two lovely professors, Tekla Harms from Amherst and John Brady from Smith. Saturday, Sunday and Monday we traveled out into our field areas in the Antelope Basin of the Gravelly Range to conduct some reconnaissance work. We familiarized ourselves with the rock formations, practiced our Brunton skills, and talked about the upcoming month.
Today, we sat down with Tekla and John to discuss our specific projects and what we would be doing individually. I will be doing geochemistry in what is termed the Madison Mylonite zone to try to determine the protolith of these highly sheared rocks by also doing the geochemistry on some of the other rock types around the region. These include diorite, schist, marble, phyllite, and many others.
The rock here is a biotite schist. The main significance, however, are the wonderful crenulations in the rock (very small folds in the rock).
The rock you are looking at here is one of the many mylonites in the area, which I will be taking samples from to do my analyses.
Mark Wilson August 9th, 2010
MAASTRICHT, THE NETHERLANDS–After mentioning the excavations in the Maastricht Formation limestones (latest Cretaceous) in the last post, I expected to be moving on the next day to a quarry. I hadn’t read the guidebook closely enough: we were planning to spend the afternoon in them! Thinking of my last geology-in-tunnels experience in Russia, I was a bit apprehensive. This time, though, the tunnels were relatively dry, much wider and taller (no sliding on your belly for 30 feet!), and far more stable.
A portion of the tunnel map painted on a wall near the entrance.
The tunnels under Maastricht are incredibly complex, the product of hundreds of years of mining. The walls often show charcoal drawings of amazing complexity, some dating back to the 17th Century. On our particular route was a Roman Catholic chapel fashioned out of a few galleries by painting the rock walls, adding statuary and carving a pulpit. It was a refuge for the Catholic community when revolutionary French soldiers took over the town at the end of the 18th Century.
Our tour had a geological purpose. We saw, in three dimensions, what may be the most complete Cretaceous-Paleogene boundary known. I learned a great deal about the end-Cretaceous extinction event, especially that the story is getting more complex and surprising. More on that in a later post.
Mark Wilson August 9th, 2010
Tunnels in the Maastrichtian Formation (Late Cretaceous) in Maastricht, The Netherlands. Location = N50.82667°, E5.67978°.
MAASTRICHT, THE NETHERLANDS–The tunnels dug into the soft Maastrichtian Formation limestones in this city have a long history starting with the Romans. At first the excavations were intended only to extract building stone, but with all the battles, sieges and other military actions in this region, residents realized that these dry and deep caves also provided places of refuge. Bakeries, chapels, storehouses and dormitories were constructed in these spaces for times of war since the Middle Ages.
During World War II, the Dutch hid several works of art in these tunnels to protect them from the Germans. These included the magnificent Night Watch by Rembrandt and The Street by Vermeer. They were guarded by Dutch military police successfully throughout the occupation. We can view this art today because of the extent, thickness and composition of this Cretaceous limestone sequence — and the courage of Dutch patriots.
Rembrandt's The Night Watch (from Wikipedia).