ENCI quarry, Sint-Pietersberg
Normally, paleontologist John Jagt, curator at the Maastricht Natural History Museum (NHMM), mainly removes objects from the limestone wall of the ENCI quarry: fossil sea urchins, flint nodules, the jaw of a mosasaur. But on September 14 last, he did something for a change. A sturdy silver-plated nail with the following in capitals: HET MAASTRICHTIEN.
A nod to the international golden spikesays Jagt, walking through the former quarry of the First Dutch Cement Industry – limestone was extracted here from 1926 to 2018. “Within geology, those gold nails form the benchmark that records the beginning or end of a geological period. Here, in the quarry, the base and top of the Maastrichtian are missing, but you do get a unique insight into the period – it is not without reason that it is named after this location. That is why a silver nail seemed like a nice alternative.”
The Maastrichtian is famous as the last phase of the Late Cretaceous, which lasted from approximately 71 million to 66 million years ago. Jagt: “Then the meteorite hit Mexico, bám, putting an end to all the dinosaurs.” At the location of what is now the Netherlands and Belgium, there was a shallow, tropical sea in which sea urchins and brittle stars lived and reptiles of more than ten meters in length swam around: mosasaurs. “One of the first mosasaur skulls ever found here in Sint-Pietersberg was taken to Paris by the French at the end of the eighteenth century.” It was a crucial fossil for paleontology because it provided famed naturalist Georges Cuvier with the first evidence that species could become extinct.
The driving of the nail, on Open Monument Day, took place at an emotional moment for Jagt. His mother had died two days earlier. “But we allowed the festivities to continue, that’s what she wanted. She knew how important Maastricht is for me.” Because Jagt is a Maastrichtian man through and through. In 2000, originally trained as an English linguist and literary scholar, he obtained his PhD at the Vrije Universiteit in Amsterdam with a thesis on the echinoderms of the Late Cretaceous and Early Paleogene: the sea urchins, sea lilies, starfish and brittle stars that also lived in that sea. “I don’t believe in a creator, but the brittle star is so beautifully put together, everything about it is just right…” Enthusiastic: “And did you know that some Neolithic tombs are decorated with sea urchins? Because of their five-sided symmetry, they resembled a natural pentagram.”
The silver nail in the marl layer between flint banks 10/11 and 12 in the ENCI quarry near Maastricht.
Chris Cologne
He wrote numerous scientific publications about the Maastrichtian period and attended dozens of conferences. His decades-long dedication to the Late Cretaceous recently earned him two important Belgian geology prizes, which were awarded in Brussels in October. At the Museum of Natural Sciences in Brussels – “in the same room where I met my wife Elena thirty years ago, she is also a paleontologist” – he received the André Dumont Medal, a prize awarded annually to a non-Belgian scientist who has made a significant contribution to earth sciences during his career. The next day he received the Paleontologica Belgica Award from the Vrije Universiteit Brussel – a recognition for paleontologists who actively collaborate with citizen scientists and involving the general public in scientific research.
Jagt recently joined a committee that will once again consider the lower limit of the period. “At Tercis-les-Bains, in the south-west of France, it was recorded almost thirty years ago with a golden spike. The limit is partly determined on the basis of the presence of one particular ammonite species, an extinct squid-like species. But that so-called guide fossil now appears not to be so characteristic of the beginning of the Maastrichtian at all. The question we are now going to consider is what that boundary does define.”
Jagt points to the nail. It also contains the name André Dumont, the namesake of the medal he has just received. “He was, in 1849, the first to suggest the name Maastrichtian and also did research as a geologist and mining expert. Here in Limburg, the layer can be studied exceptionally well; in Amsterdam, for example, you have to go 700 meters deep into the ground. But we still only know so little” – he holds his thumb and index finger a centimeter apart – “of the Maastrichtian.”
For this reason, he and colleagues from Maastricht University, the Vrije Universiteit Brussel and the Catholic University of Leuven started the Maastrichtian Geoheritage Project six years ago. “Our goal was to obtain as detailed a picture of the limestone wall in the quarry as possible, based on drone research and rock samples, among other things. We have now discovered that there is a period of 21,000 years between the various horizontal flint banks, which are located at regular intervals from each other in the limestone package. A clear rhythm that seems to be linked to the so-called precessional movement of the earth’s axis. In just over For 21,000 years, the Earth wobbles around its own axis like a top, and that causes variations in the climate. We now suspect that something in that climate fluctuation causes a large-scale reaction between silicon and oxygen, creating an extra amount of flint. But we still have to find out what exactly that is: you cannot simply recreate flint in the lab.”
He drove the Silver Spijker between flint banks 10/11 and 12, a period in which an abrupt warming took place. “You can see from the fossil composition that a changing of the guard took place: first many sea urchins of the genus Echinocorys before, but in the warmer seas it acquired sex Hemipneustes the upper hand.”
Sampling the wall is very structured, he says: a rock sample is taken every 5 centimeters. With a longing look at the limestone bank: “Sometimes you see the sea urchins sitting so well… Then it really takes self-control not to cut them out right on the spot.”
Chalet d’n Observant, Sint-Pietersberg
On the terrace next to the quarry, in the autumn sun, Jagt and photographer Chris Keulen talk about the difference between looking and observing: after all, just because you look at something does not necessarily mean that you actually see it. Just like in photography, seeing is essential in paleontology, Jagt emphasizes. “You sometimes have to be able to distinguish species from each other on the basis of minute details. In my opinion, artificial intelligence is also a real problem when it comes to taxonomy. The computer gives the impression that it can name species perfectly, but that is not always the case. Human perception remains essential, all that knowledge must not disappear. Otherwise you run the risk that paleontologists will no longer even be able to see a bivalve [een tweekleppig schelpdier, GV] of a brachiopod [een ánder tweekleppig schelpdier] can distinguish.”
He himself started making accurate observations at an early age: as a seven-year-old he heard from a teacher at school in Venlo about fossils in Namur bluestone, a gray, fine-grained type of limestone. “My grandmother had exactly such a block in the garden at home, so I immediately hammered it to pieces – without her permission. I found a piece of coral, my very first fossil.”
Many fossils from the Maastrichtian have been found in the ENCI quarry near Maastricht.
Chris Cologne
Later he bought his first fossil sea urchin in a souvenir shop in Valkenburg. And as a high school student he traveled by train to South Limburg and walked dozens of kilometers along old quarries in search of fossils. “Then I came home with 35 kilos of Paleocene limestone in my backpack.”
He sees the same enthusiasm in many young museum visitors. “They are so interested. Yes, sometimes they are disappointed when they discover that the mosasaurs in our collection are not real dinosaurs. But in the end they find a giant sea-dwelling reptile at least as cool.” Laughing, he points to a group of ducks. “Look, there are some living dinosaurs!”
Natural History Museum Maastricht, De Bosquetplein
The employees of the Maastricht Natural History Museum form a close-knit team, which consists not only of permanent employees but also of dozens of volunteers, says Jagt. “I cannot emphasize enough how important they are for us – in preparation, in developing digital animations, but also in the search for new fossils.” The word amateur wrongly has a negative connotation, he emphasizes. “I am extremely proud to be an amateur, to be an enthusiast.”
The team is currently working on a new design for the museum. In the museum café, Jagt explains the plans with his colleague, chief curator Astrid Smeets: the design as it is now will be completely overhauled. “It has been virtually unchanged for decades. We are going to change that,” says Smeets. “The emphasis will be much more on biodiversity. We want to tell the bigger story of life during the Cretaceous period – besides the mosasaurs, there were so many other interesting things swimming and crawling around in those tropical seas.” Jagt: “Although Bèr will of course remain part of the collection.” That 11-meter-long mosasaur was unearthed in the ENCI quarry in 1998.
You remain a paleontologist for life
The museum, which dates from 1912, still houses all kinds of treasures in the depot that have rarely or never been exhibited, he says. “Think of letters from Eugene Dubois, the Limburger who later found the first remains of it in Indonesia Homo erectus discovered. To the collection of Mien van de Geijn, who received her PhD in 1937 as one of the first female paleontologists. Or the Wasmann collection, an ant collection that was temporarily stolen by the Germans during the Second World War.” Heinrich Himmler, among others, was interested in insects, although it was not a pure hobby: he also wanted to see how they could be used to transmit diseases. What does not end up in the new exhibition will be transferred to an open depot in the nearby Center Céramique, says Smeets. “Students, researchers and volunteers can consult the collection there. What’s so nice is that everything in the collection comes from the area.”
In 2.5 years, Jagt will have to retire from the museum, he says with nostalgia in his voice at the end of the conversation. But the man who has already described more than 275 new fossil species, genera and families in his career is not thinking about stopping any time soon. “You stay a paleontologist for life.”
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