Zapadnaya
Key facts
- Country
- Ukraine
- Diameter
- 3.2 km
- Age
- about 165 ± 5 million years
- Location
- 49.73° N, 29.00° E
Nothing obvious: the small crater lies beneath farmland and woodland in Zhytomyr Oblast, central Ukraine.
Zapadnaya is a small impact crater about 3.2 km across in Zhytomyr Oblast, central Ukraine. Its name means 'western'.
What it hit. The impactor struck ancient crystalline rocks of the Ukrainian Shield, mainly granites. The crater was later filled with sediments.
Diamonds from an impact. Zapadnaya is one of the places where impact diamonds have been found. These tiny diamonds form when graphite, a soft form of carbon present in the target rock, is squeezed by the enormous pressure of the shock wave and instantly turns into diamond. Such diamonds are very small and of no use as gems, but they are a clear sign of impact.
Proof of impact. Besides impact diamonds, the rocks contain breccias, impact melt rock and minerals with shock features. Drilling has outlined the shape of the crater.
Age. Argon dating of the melt rock gives an age of about 165 million years, in the Middle Jurassic, with an uncertainty of about 5 million years.
Why it matters. Zapadnaya helps scientists understand how diamonds form in impacts, a process seen on a much larger scale at Popigai in Siberia. The impactor is unknown.
Did you know?
Tiny impact diamonds have been found at Zapadnaya.
Its name means 'western'.
The diamonds formed when graphite in the rock was squeezed by the shock wave.