Puchezh-Katunki
Key facts
- Country
- Russia
- Diameter
- 40 km
- Age
- 195.9 ± 1.0 million years
- Location
- 56.97° N, 43.72° E
Almost nothing: the structure lies beneath forest and farmland on the Volga, between Nizhny Novgorod and Ivanovo. Impact rocks are exposed in a few places on the river banks.
Puchezh-Katunki is a large impact structure on the Volga River in European Russia, between the cities of Nizhny Novgorod and Ivanovo. The main crater is about 40 km across from rim to rim, and the whole disturbed area, including an outer terrace, is about 80 km wide.
What it hit. The impactor struck a sequence of Palaeozoic sedimentary rocks, about 1.7 km thick, lying on ancient crystalline basement of the East European Craton. The impact excavated deep into the basement, and the rebound of the floor formed a central uplift.
Discovery and proof. The structure was recognised as an impact crater in the 1960s and 1970s by Soviet geologists, who found breccias, impact melt rocks and minerals with shock features. Impact diamonds have also been reported, formed from graphite in the target rocks. A deep research borehole, drilled at Vorotilovo in the central uplift, passed through more than 5 km of shocked and broken rock.
Age. The most precise argon dating of the melt rock gives an age of about 196 million years, in the Early Jurassic. An earlier estimate of about 167 million years has been revised.
What can be seen. The structure is almost completely buried under younger sediments. It can be traced on the ground only by subtle differences in vegetation and by outcrops of impact rock on the banks of the Volga.
Why it matters. Puchezh-Katunki is one of the largest impact structures in Europe. The impactor is unknown.
Did you know?
A research borehole drilled into Puchezh-Katunki passed through more than 5 km of shocked rock.
Impact diamonds have been reported from the structure.
The whole disturbed area is about 80 km wide.