Archive for August 10th, 2010

Geology and religion: le Grand Animal de Maastricht

August 10th, 2010

The discovery of a mosasaur in the Maastricht tunnels (1770). Engraving by G. R. Levillaire; image from Wikipedia.

MAASTRICHT, THE NETHERLANDS–Next month I am giving a talk on campus about evolution in a lecture series on “science and religion”. I was particularly intrigued, then, to hear a story about the famous mosasaur discovered in the Maastricht tunnels that highlighted tension between geology and the religious establishment long before Charles Darwin started rocking boats. It was a delight to be in the very tunnels where the drama began.

In 1770 a group of quarrymen in Maastricht discovered the skull of a very large and toothy animal. It was brought to the attention of Johann Leonard Hoffman, a local surgeon and fossil collector, who immediately knew it was very curious and would be of great interest to the savants of Europe. He corresponded with many, producing what we would call a buzz today about this creature. It clearly represented an animal which went extinct — a new concept at the time. How do you explain the existence of a large fossil like this deep underground in The Netherlands? Was it an animal which missed Noah’s Ark? Did God create some animals doomed to extinction?

In 1794 an army from revolutionary France occupied Maastricht. Some officers wanted to seize the fossil and put it on display in Paris because of these questions about God and Creation. They wanted to use this mosasaur (the name came much later) to show that either there was no God or that God was a distant deity unconcerned with Creation. Apparently through bribery and rewards, they found the fossil and indeed shipped it off to Paris. To this day it is in the Paris Museum of Natural History and only a cast of it is in the Maastricht Natural History Museum. (The Dutch have various ways to remind visitors that the French stole the original specimen. European unity only goes so far!)

Cast of the famous Maastricht mosasaur in the Maastricht Natural History Museum.

In Paris the famous geologist Georges Cuvier took an interest in “le Grand Animal de Maastricht” and correctly identified it as a reptile — specifically a kind of marine lizard (a conclusion still supported today). Cuvier used it as evidence for his catastrophic ideas of disasters followed by re-creations of life on Earth.

The Maastricht mosasaur, now known as Mosasaurus hoffmanni, thus was one of the first fossils to be used in the science-religion debates, and this was well before the modern theory of evolution emerged.

Mosasaur skeleton reproduction in the Maastricht Museum of Natural History.

The best Cretaceous-Paleogene boundary yet

August 10th, 2010

MAASTRICHT, THE NETHERLANDS–The Cretaceous-Tertiary boundary (K/T, or as I should be writing, the “Cretaceous-Paleogene” boundary, or K/Pg) has been one of the Wooster Geology themes this summer. We saw it in Alabama and Mississippi in May, and in Israel in June. The view of it here in The Netherlands, though, is far different. We explored it from below in the Maastrichtian tunnels at Geulhemmmerberg (N50.86692°, E5.78357°). This three-dimensional view, combined with the fact that this boundary section may be the most complete ever found, made today very special. We had a secular geological pilgrimage to the mysterious global events at the end of the Cretaceous.

After walking a long distance through the maze of tunnels guided by John Jagt of the Maastricht Natural History Museum and Rudi Dortangs, a very keen and accomplished amateur paleontologist (with a new mosasaur to his credit), we came upon excavations at the roof line which uncovered a thick sequence of clays and carbonate sand mixed together. The K/Pg boundary is a highly-irregular hardground surface with many Thalassinoides burrows penetrating up to two meters below. Carbonate sands are directly above the boundary, with the clay layers of varying vertical distances but rarely sitting on the hardground. There are at least seven clays, with the largest (Layer D) several centimeters thick. Since this boundary is near the roof of the tunnels, the bottom layers were often the ceiling above us so that we could see the very latest Cretaceous and earliest Paleogene exposed as a kind of upside-down bedding plane.

Two big surprises for: I knew there were multiple clay layers in some places, but to finally see them made them real for me. The traditional view since 1980 has been one clay layer representing the dust and debris from the meteorite impact settling back to Earth. Multiple clay layers makes this story much more complex, especially since some of the layers combine and split laterally. Maybe they were reworked during the storms of that “Global Winter”?

The second surprise was to learn that there were ammonites which definitely survived the extinction and lived briefly in the Paleogene. When these fossils were first found it was assumed they had been reworked from the Upper Cretaceous, but new studies show that they contain sediments which are indisputably Paleogene. Whether this is enough for us to change the textbooks is an interesting question: there are so few of the fossils, and in even fewer places. Nevertheless, some ammonites extend into the Paleogene.

Andrej Ernst and John Jagt at the boundary section in the Maastrichtian tunnels at Geulhemmmerberg.

This is a day I will always remember. For a historical geologist like me, it doesn’t get better!