A quarry face that uniquely depicts the geological changes at the boundary of the two Cretaceous periods Turonian and Coniac. The former limestone quarry is thus regarded as a global reference point for the time boundary 89.4 million years ago - an epoch in which dinosaurs still lived. This was announced by the International Union of Geological Sciences, which has awarded the stratigraphic profile the important title of "Global Stratotype Section and Point" (GSSP).
An international team of geoscientists led by Prof. Silke Voigt from Goethe University Frankfurt, Prof. Ireneusz Walaszczyk from the University of Warsaw and with the support of Dr. André Bornemann from the State Office for Mining, Energy and Geology (LBEG) 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 from Turon to Coniac unbroken and therefore represents a perfect rock sequence to serve geoscientists from all over the world as a reference for their research in the future - as a "Global Stratotype Section and Point (GSSP)" or, in geoscientific jargon, a "golden nail". Just as the international film industry uses the Oscar as its highest award, the "Golden Nail" is only awarded to reference points of outstanding geological significance. There is only one other "Golden Nail" in Germany, the Wetteldorfer Richtschnitt in the Eifel.
The Coniac is accompanied by certain types of shells, known as inocerams, which can be found in large numbers in Salder. "The inoceram species Cremnoceramus deformis erectus is found for the first time in a certain layer, marking the time limit," says Prof. Silke Voigt. With this reference point, geological layer profiles can be compared with each other worldwide and classified chronologically.
The awarding of the title will now become official and visible in a festive ceremony. On Tuesday, September 19, at 11.30 a.m., members of the "International Stratigraphic Commission" will hammer the "Golden Nail" into the rock face of the Salder Quarry to honor this special point in the Earth's history. Scientists from six nations, the participating research institutions, representatives of local politics and the UNESCO Geopark Harz - Braunschweiger Land - Ostfalen are expected to attend the ceremony in Salder to celebrate this significant event.
"It is a special pleasure and honor for us to have this outcrop, which is now so important for geosciences, in our Geopark. In consultation with the landowner, we will ensure that the geotope is looked after so that it can be preserved for scientific research and educational tours," emphasizes Henning Zellmer, Managing Director of the Geopark. "This unique point for Lower Saxony shows the importance of the classic geological and stratigraphic work at universities and also at the State Office for Mining, Energy and Geology," emphasizes Markus Stöwer, Head of Department at the LBEG.