In August 2010 I had a fantastic geologic field trip to the tunnels of Geulhemmmerberg, The Netherlands, to see an unusual exposure of the Cretaceous-Paleogene boundary. There I collected a fist-sized sample of the famous boundary clay, which is found in a variety of thicknesses around the world. I knew just what to do with this sticky handful: give it to my artist friend Walt Zurko at The College of Wooster. He generously made the gorgeous cup-like object above and presented it to me this week.
Walt used every scrap of the clay, even recycling the shavings back into the exterior. There were tiny rock fragments in the original clay sample. They expanded differentially during the heating process and one made a small crack at the lip. I like it — it gives the piece character, like the crack in the Liberty Bell. Walt used several techniques to produce an extraordinary patina on the outside, much of which is not adequately conveyed in my amateur image.
Now we have in the geology department at Wooster a beautiful work of art made from the most famous clay in geological history. Aren’t the liberal arts wonderful?
Inside the tunnels at Geulhemmmerberg, The Netherlands, in August 2010. The rock forming the ceiling is Paleogene and most of the walls are made of Cretaceous limestone. The Cretaceous-Paleogene boundary is visible about a third of a meter down from the top of the wall in the background.
The complicated Cretaceous-Paleogene boundary at Geulhemmmerberg, The Netherlands. This gray clay is one of the thickest boundary clays in the world. I collected a chunk from this section for Walt’s artistic creation.
I’m envious! Will you put it on display in the department? Looking forward to zapping the clay on our XRF. What else can we do with the clay?
Yes, let’s figure out a good place to put it — maybe in the case outside my office. A table showing its chemical and mineralogical composition could accompany it! I wonder what the rock fragments are?
I love the fact that you included the penny for contrast, as per your other specimens!
Mark, what does it take to obtain a cross-sectional sample of the K/Pg boundary like the last photo you have in this post? I attempted obtaining something myself using the exposed layers near the Brazos river in Texas, but the samples are so incredibly fragile.
Hello Andy. That boundary section is indeed crumbly. I don’t think you can get a continuous sample at that outcrop, but you can certainly get a series of discrete samples.