These beauties hail from Jurassic, Lower Callovian outcrops in the Quarry of Kursk Magnetic Anomaly (51.25361,37.66944), Kursk region, Russia. Diameter ammonite 70ΠΌΠΌ.
In the mid-1980s, during the expansion and development of one of the quarries, an unusual geological formation was found. This area had been part of the seafloor around an ancient island surrounded by Jurassic Seas.
The outcrops of this geological formation turned out to be very rich in marine fossil fauna. This ammonite block was found there years ago by the deeply awesome Emil Black.
In more recent years, the site has been closed to fossil collecting and is in use solely for the processing and extraction of iron ore deposits. Kursk Oblast is one of Russia's major producers of iron ore. The area of the Kursk Magnetic Anomaly has one of the richest iron-ore deposits in the world. Rare Earth minerals and base metals also occur in commercial quantities in several locations. Refractory loam, mineral sands, and chalk are quarried and processed in the region.
The Kursk Magnetic Anomaly Quarry is not far from the Sekmenevsk Formation or Sekmenevska Svita in Russian, a Cretaceous (Albian to Cenomanian) terrestrial geologic formation where Pterosaur fossils have been found in the sandstones.
If you head there for a visit, be sure to check out the Sekmenevska Svita and Oblast's artesian-well water — most refreshing!