A geological formation that perfectly depicts the transition between the Cretaceous Turonian and Coniac periods. The team has characterized the former limestone quarry in the northeast of the Salzgitter mountain range so precisely that it is now considered a global reference point for the turn of time 89.4 million years ago. This was announced by the International Union of Geological Sciences, which awarded the stratotype profile the title "Global Stratotype Section and Point" (GSSP).
The international team of geoscientists examined 40 meters of the geological layer sequence in the former limestone quarry on the Hasselberg in detail. The researchers discovered that only here is the transition between Turon and Coniac unbroken and therefore represents a perfect rock sequence for geoscientists from all over the world to use as a reference for their research.
Certain types of shells, known as inocerams, occur with the Coniac and can be found in large numbers in Salder. In layer 46 of the quarry, the German-Polish scientific team discovered that the inoceram species Cremnoceramus deformis erectus was found for the first time, marking the time boundary, as well as other microfossils and a characteristic change in the ratio of the carbon isotopes 12C and 13C, a so-called negative anomaly in the carbon cycle.
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In the limestone quarry on the Hasselberg near Salzgitter-Salder in the north-east of the Salzgitter mountain range, limestone and marl were once mined for the cement industry and finally for ore processing. Today, the site is a well-known biotope and geotope owned by the Natural Landscape Foundation, which was set up by the BUND regional association of Lower Saxony. While the care of the quarry site has been transferred to the Salzgitter district group of BUND, the UNESCO Geopark Harz-Braunschweiger Land-Ostfalen takes care of the geoscientific part of the quarry. The quarry is not freely accessible for nature conservation reasons, but guided hikes are occasionally offered.
90 million years ago, in the second half of the Cretaceous, it was tropically warm on earth: the ice-free poles ensured a high sea level and Central Europe consisted of a cluster of islands. In the sea, ammonites developed an immense variety of forms, on land the dinosaurs ruled. The first flowering plants began to compete with horsetails and ferns. 89.39 million years ago, the climate began to cool slightly and the sea level began to fall slightly from its peak: a new geological period, the Coniac Age, replaced the Turonian Age.
