Finds

What does a snail have to do with heat storage? Tiny fossils dating back about 20 million years were discovered in the drill cuttings from DeepStor-1. They tell us what the Karlsruhe region once looked like.

Dunkle versteinerte Schnecke mit schönen Windungen im Bohrklein — Snail from the Lower Landau Formation at a depth of about 520 m

Kleine weiße Schnecke inmitten aus Bohrklein — Small snail from the Landau Formation, found at a depth of about 215 m

Zu sehen sind drei verschiedene Arten mit schwarzen, braunen und farblosen Schalen. — Fossilized shells from the Bruchsal Formation at a depth of 620 m.

Schwarze Schalen inmitten von Bohrklein. — A rock sample from the Landau Formation, collected from a depth of about 200 m.

Drill cuttings are actually quite unspectacular: crushed rock that is flushed to the surface along with the drilling fluid. But if you look more closely, you can sometimes find little treasures in them.

And indeed, upon closer inspection and under the microscope, small snail shells and shells of ostracods—also known as shell crabs—were found in the drill cuttings from depths of approximately 200 to 550 meters.

They originate from the Landau and Bruchsal formations. These layers lie beneath the younger sands and gravels and extend to a depth of about 800 meters at this site. They were deposited approximately 16 to 25 million years ago, when the region was characterized by lakes and rivers and was repeatedly flooded by the sea.

The snail from the Lower Landau Formation is a freshwater species. It is sometimes found in brackish water as well. It therefore likely lived in a lake or calm body of water that once stretched across the Upper Rhine Graben. In that warm climate, palm trees likely grew along the shore rather than the pine trees found today in the Hardtwald. In the underlying Bruchsal Formation, three different species of ostracods were found, with black, brown, and colorless shells.

For research, such finds are more than just pretty specimens. Fossils reveal the conditions under which a rock layer was formed and help determine the sequence of layers and better understand the subsurface. If fossils are particularly characteristic of a formation, they are called index fossils.

Our page on geology shows how the geological layers beneath the KIT Campus North are structured.