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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.
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