On Sunday, September 20, 2026, the City Museum at Salder Castle in Salzgitter invites you to “Geotope Day” at the limestone quarry in Salzgitter-Salder from 11 a.m. to 1 p.m. Registration is required!

The Am Hasselberg quarry in Salder is an extraordinary geosite within the UNESCO Harz–Braunschweiger Land–Ostfalen Geopark. The site is owned by the Naturlandschaft Foundation and is maintained and managed by BUND Salzgitter. For nature conservation reasons, access to the quarry is strictly prohibited. “Geotope Day” is therefore a special opportunity to visit the site by registration.

The Am Hasselberg quarry is special in many ways: Since limestone mining was permanently halted in 1992, small biotopes with a unique and particularly valuable biodiversity have developed on the quarry site largely through natural processes. Protected species of sand snails are native here, and the eagle owl uses the area as a breeding ground. But the quarry also stands out geologically: The limestone layers reveal a pivotal boundary in Earth’s history—the transition from the Turonian to the Coniacian epochs approximately 90 million years ago. It was precisely at this spot that the “Golden Nail” was placed in 2023. This marks an internationally recognized geological reference point and makes the Salder quarry a globally significant site for the geosciences.

In the Cretaceous quarry in Salder, one can still find, after more than 90 million years, traces of organisms that inhabited the Cretaceous sea at the end of the Mesozoic Era. The most common finds are remains of brachiopods, ammonites, sea urchins, mussels, and sponges—and, though rarer, teeth from sharks and other marine creatures have also been found here. On “Geotope Day,”
of the Geotope,” interested visitors can set out in search of fossilized traces of bygone eras and make their own small discoveries.

The Salder Castle Municipal Museum asks participants to bring a helmet, safety goggles, and a hammer. However, these items can also be borrowed on site while supplies last. The terrain is rugged; surefootedness and sturdy footwear are required. The guided tour is only possible in dry weather.