“Our fossil collections are still a source of new discoveries”
Jan Ove Ebbestad takes out a large trilobite from the collections. Trilobites lived in the oceans and died out 252 million years ago. Photo: Marcus Holmqvist, Uppsala University
The Museum of Evolution in Uppsala has a very large collection of fossils. Some of them are featured in a new richly illustrated book entitled Sveriges geologi: en resa i tid och rum [Sweden’s geology: a journey through time and space]. One of the book’s co-authors, Jan Ove Ebbestad, is a researcher and curator at the museum. We visited him at his workplace to learn more.
You wrote two chapters of the book. What are they about?
They are about the Ordovician period 485–444 million years ago and the Silurian period 444–419 million years ago. Sediments and deposits from these two periods are particularly well developed in Sweden.
Where can they be found?
In Sweden, Ordovician deposits are mainly found in Östergötland, Västergötland, northern Jämtland and Dalarna. Silurian deposits are mainly found on Gotland.
What kind of life existed in Sweden at that time?
There was incredible biological diversity. The Ordovician period in particular saw the greatest increase in biodiversity in the history of the Earth in terms of animal groups. We start with the classic red orthoceratite limestone with lots of squid. During the middle of the Ordovician period, the waters in Sweden became a little deeper. We get other groups such as brachiopods and trilobites. At the end of the Ordovician period, we see the development of large reef-like structures, especially in Dalarna. The Bodakalk there is one of the most species-rich fossil beds we have in Sweden. It contains over 90 species of trilobites alone, and 65 species of squid have been documented.
What about the Silurian period?
During the transition to the Silurian period, the oceans became warmer. Our land area was close to the equator. Limestone reefs formed. Corals were very common. Every reef-dwelling organism imaginable was found here.
How did you end up writing these chapters?
I’ve been working with fossil deposits from these periods over my entire 30-year career. So it seemed only natural for the book’s editor-in-chief, Vivi Vajda, to contact me when she was working on this book.
What was it like working on this project?
It was a very exciting challenge to find up-to-date and relevant literature that reflects the research being done on these periods and then try to match it with the fossils we have in our collections. They are an incredible source for books like this one. We have such a wealth of species in our collections. They have been here at the museum for almost 200 years and are still a source of new information and new discoveries.
How many fossils do you have today?
We are in the process of significantly expanding the collection. It’s growing rapidly, mainly because we are taking over material from the Geological Survey of Sweden (SGU). In recent years, we’ve also systematically expanded the collection with Swedish material. Today we have at least 400,000 fossils, but an estimated one million more are on their way. This will make it the largest fossil collection in Scandinavia.
Åsa Malmberg