Basaltsteinbruch Weitendorf, Natural monument and quarry in Wildon, Austria

Basaltsteinbruch Weitendorf is an active quarry near Wildon that extracts dark volcanic rock. The quarry walls display distinctive columnar rock formations in the lower sections, with stone ranging from dark gray to black in color.

The basalt comes from the Weitendorf volcano, a Middle Miocene shield volcano active 14.5 to 15 million years ago. Its existence was first suspected in the 1830s. The quarry later became known for minerals and fossils, and parts of it have been a natural monument since 1985.

The clay marls beneath the basalt have yielded over 100 species, including the turret snail Turritella badensis, which forms a bed up to 50 cm thick. The long-snouted snail Tibia dentata and the conch Strombus schröckingeri were found in Austria only at Weitendorf and Wetzelsdorf. A tooth of the giant shark Otodus megalodon, over 15 m long, was also recovered here.

The quarry is an active mining site with restricted visitor access for safety reasons. It is advisable to check conditions beforehand and maintain respectful distance from work vehicles and operational areas.

Groundwater accumulates within the quarry to form a lake that may be repurposed as thermal storage for the city of Graz. This creative reuse plan shows how mining sites can become infrastructure assets for energy systems after extraction ends.