In the quarry at Hellenköpfchen, we come across a special rock that can be seen here in its typical formation. It is the so-called
Züschen quartz ceratophyric tuff, a rock of volcanic origin that was formed in the Lower Devonian period around 390 million years ago. In the quarry, it reaches a thickness of around 3 m and is embedded between clay shales. The clays were deposited as muds in a shallow Lower Devonian sea. Volcanic activity in the vicinity of Züschen caused volcanic ash to be thrown into the air, fall back into the sea and cover the clay muds like a thin carpet. Submarine currents mixed and rearranged the clay and ash. This also embedded the remains of marine life at the time, which is why the Züschen quartz ceratophyre tuff and the surrounding clay shales are rich in fossils. There are mainly trilobites (three-lobed crustaceans), brachiopods (arthropods), corals, crinoids (sea lilies), mussels and a few snails.
Age of the rocks: Emsian stage, Lower Devonian (around 390 million years ago)
Use of the rocks: Tuff is a relatively soft rock and can be easily processed as natural stone. In other places, this type of rock is therefore often used as a building material, especially for façade panels and window sills. However, there is no evidence of quartz ceratophyte tuff being used in the municipality of Züschen.