Steinhardt Erbsen

The winegrowing village of Steinhardt, which belongs to Bad Sobernheim, was 35 million years ago, in the Oligocene era, on the edge of a shallow subtropical sea whose coastline ran along the Kreuznach Basin and Staudernheim Bay. The sand mined in the Steinhardt sand pits dates from this period. This sand contains the famous "Steinhardter Erbsen" (Erbsen=peas): round, pea-shaped, sometimes slightly elongated sandstone spheres, which often contain plant and animal fossils. Shape and size of the sandstone spheres often indicate the enclosed fossil (up to 17cm long spruce cones have been found!). Since the sea in the Middle Oligocene had initially retreated by raising the Upper Rhine Graben, and after a renewed lowering it advanced west again to Bad Sobernheim, two layers of sand can be distinguished here: the "lower" and the "upper" sea sand. In the deeper area there are the Steinhardter Erbsen with maritime fossils, while in the sandstone spheres of the upper area mainly plant remains are enclosed, especially conifer cones, mostly of larches, pines and spruces. Two species of snails can also be found in the upper sea sand. The Steinhardter Erbsen were probably formed near the shore in warm, barium chloride-bearing thermal baths, which obviously only existed in the Steinhardt region. The plants and animals decaying in the immediate vicinity of such thermal baths formed hydrogen sulphide, which reacted with the barium chloride of the thermal baths to barite, whereby the sand around the fossils was enclosed and fossilized.

Photo: 35 million years old "Steinhardt Erbsen" with enclosed plant fossils.